Tunable mid-infrared and far-infrared laser output was demonstrated based on BaGa_(4)Se_(7)crystals and an optical parametric oscillator(OPO).With a 1.06μm Nd:YAG laser and a double-pass singly resonant OPO cavity,a ...Tunable mid-infrared and far-infrared laser output was demonstrated based on BaGa_(4)Se_(7)crystals and an optical parametric oscillator(OPO).With a 1.06μm Nd:YAG laser and a double-pass singly resonant OPO cavity,a laser energy output of 2.2 mJ at 10μm was obtained.By tuning the angle and temperature,a tunable laser output covering the wavelength range from 6μm to 17μm was obtained with a tuning precision better than 3 nm.The corresponding optical-to-optical conversion efficiency was 2.8%,and the slope efficiency was 4.4%.The damage effect of the output laser on detectors was also investigated,and point damage to the detector occurred at an output energy of 16.4μJ.The laser system has the advantages of miniaturization,a wide tuning range,high energy and high tuning resolution.Its broadband laser characteristics make it highly valuable for applications in atmospheric detection,infrared spectroscopy and electro-optical countermeasures.展开更多
We demonstrate the growth,thermal,spectroscopy and laser performance of an Er3+doped Gdo.iYo.9AlO3(Er:GYAP)disorder crystal grown by Czochralski method.The crystal with space group Pbnm and lattice parameters of a=0.5...We demonstrate the growth,thermal,spectroscopy and laser performance of an Er3+doped Gdo.iYo.9AlO3(Er:GYAP)disorder crystal grown by Czochralski method.The crystal with space group Pbnm and lattice parameters of a=0.5185 nm,b=0.5327 nm,c=0.7378 nm,α=β=90°and V=0.203784 nm3 are obtained by fitting powder X-ray diffraction data.The Mohr's hardnesses along three axes are 6.94,7.27,and 7.44.The thermal expansion coefficient of b axis is 4.20×10^(-6)k^(-1)and the density is 5.88 g/cm3.The thermal conductivities are characterized as K_(a)=6.24,K_(b)=5.57,and K_(c)=6.83 W/(m·K).Meanwhile,the refractive index,absorption and emission spectra in triaxial di-rections are determined.Besides,level lifetimes of 4l11/2 and 413/2 are 0.86 and 2.83 ms.Finally,the~2.7μm multiwavelength laser outputs are observed with maximum average power of 628 mW and beam quality factors M_(x)^(2)/M_(y)^(2) of 1.42/1.45.The results prove that the Er:GYAP crystal is a promising gain medium for generating mid-infrared lasers.展开更多
Accurate and comprehensive knowledge of the atmospheric environment and its evolution within the coastal ocean boundary layer are necessary for understanding the sources,chemical mechanisms,and transport processes of ...Accurate and comprehensive knowledge of the atmospheric environment and its evolution within the coastal ocean boundary layer are necessary for understanding the sources,chemical mechanisms,and transport processes of air pollution in land,sea,and atmosphere.We present an overview of coastal ocean boundary layer detection technology and equipment in China and summarize the progress and main achievements in recent years.China has developed a series of coastal ocean boundary layer detection technologies,including Light Detection and Ranging(LIDAR),turbulent exchange analyzer,air-sea flux analyzer,stereoscopic remote sensing of air pollutants,and oceanic aerosol detection equipment to address the technical bottleneck caused by harsh environmental conditions in coastal ocean regions.Advances in these technologies and equipment have provided scientific assistance for addressing air pollution issues and understanding land-sea-atmosphere interactions over coastal ocean regions in China.In the future,routine atmospheric observations should cover the coastal ocean boundary layer of China.展开更多
Considering the atmospheric extinction and turbulence effects,we investigate the propagation performances of supercontinuum laser sources in atmospheric turbulence statistically by using the numerical simulation metho...Considering the atmospheric extinction and turbulence effects,we investigate the propagation performances of supercontinuum laser sources in atmospheric turbulence statistically by using the numerical simulation method,and the differences in propagation properties between the super-continuum(SC)laser and its pump laser are also analyzed.It is found that the propagation characteristics of super-continuum laser are almost similar to those of the pump laser.The degradation of source coherence degree may cause the relative beam spreading and scintillation indexes to decrease at different propagation distances or different turbulence strengths.The root-mean-square value of beam wandering is insensitive to the variation of source correlation length,and less aperture averaging occurs when the laser source becomes less coherent.Additionally,from the point of view of beam wandering,the SC laser has no advantage over the pump laser.Although the pump laser can bring about a bigger aperture average,the SC laser has a lower scintillation which may be due to the multiple wavelength homogenization effects on intensity fluctuations.This would be the most important virtue of the SC laser that can be utilized to improve the performance of laser engineering.展开更多
We demonstrate a high-energy and high-power pulse laser on a xenon lamp-pumped Er:YAP crystal. The laser performance and thermal focal lengths under different working frequencies are discussed. The results show that t...We demonstrate a high-energy and high-power pulse laser on a xenon lamp-pumped Er:YAP crystal. The laser performance and thermal focal lengths under different working frequencies are discussed. The results show that the thermal lens effect is gradually aggravated with the increase of working frequencies, and even working at 100 Hz, a single pulse energy of 234 m J can be achieved. A maximum average power of 41.5 W is achieved with a working frequency of 20 Hz and slope efficiency of 2.82%. This output power is much higher than other xenon lamp-pumped erbium laser devices.A Q-switched laser is demonstrated by using the TeO2crystal, the maximum output energies of 11.5 m J and 3.5 m J are obtained at 50 and 100 Hz, the corresponding peak powers are 93.4 k W and 17.2 kW, respectively.The laser wavelengths and beam quality factors are also characterized in the free-running and Q-switched modes. A higher pulse energy and peak power laser could be achieved further by improving the damage threshold of TeO2acousto-optical Q-switching. All the experimental results illustrate that the xenon lamp-pumped Er:YAP laser is a promising candidate for high-power and high-frequency mid-infrared laser devices.展开更多
The optimal spectral excitation and acquisition scheme is explored by studying the effect of the lensto-sample distance(LTSD)on the spatial homogeneity and emission spectra of flat-top laser converging spot induced pl...The optimal spectral excitation and acquisition scheme is explored by studying the effect of the lensto-sample distance(LTSD)on the spatial homogeneity and emission spectra of flat-top laser converging spot induced plasma.The energy distribution characteristics before and after the convergence of the laser beam with quasi flat-top intensity profile used in this study are theoretically simulated and experimentally measured.For an aspheric converging mirror with a focal length of100 mm,the LTSD(106 mm≥LTSD≥96 mm)was changed by raising the stainless-steel sample height.The plasma images acquired by ICCD show that there is air breakdown when the sample is below the focal point,and a ring-like plasma is produced when the sample is above the focal point.When the sample is located near the focal point,the plasma shape resembles a hemisphere.Since the spectral acquisition region is confined to the plasma core and the image contains all the optical information of the plasma,it has a lower relative standard deviation(RSD)than the spectral lines.When the sample surface is slightly higher than the focal plane of the lens,the converging spot has a quasi flat-top distribution,the spatial distribution of the plasma is more uniform,and the spectral signal is more stable.Simultaneously,there is little difference between the RSD of the plasma image and the laser energy.In order to further improve the stability of the spectral signal,it is necessary to expand the spectral acquisition area.展开更多
Urban tree species provide various essential ecosystem services in cities,such as regulating urban temperatures,reducing noise,capturing carbon,and mitigating the urban heat island effect.The quality of these services...Urban tree species provide various essential ecosystem services in cities,such as regulating urban temperatures,reducing noise,capturing carbon,and mitigating the urban heat island effect.The quality of these services is influenced by species diversity,tree health,and the distribution and the composition of trees.Traditionally,data on urban trees has been collected through field surveys and manual interpretation of remote sensing images.In this study,we evaluated the effectiveness of multispectral airborne laser scanning(ALS)data in classifying 24 common urban roadside tree species in Espoo,Finland.Tree crown structure information,intensity features,and spectral data were used for classification.Eight different machine learning algorithms were tested,with the extra trees(ET)algorithm performing the best,achieving an overall accuracy of 71.7%using multispectral LiDAR data.This result highlights that integrating structural and spectral information within a single framework can improve the classification accuracy.Future research will focus on identifying the most important features for species classification and developing algorithms with greater efficiency and accuracy.展开更多
The melting process of ice crystal particles has a significant effect on weather forecasting and global climate.Millimeter waveband is an excellent frequency range for exploring the optical characteristics of ice crys...The melting process of ice crystal particles has a significant effect on weather forecasting and global climate.Millimeter waveband is an excellent frequency range for exploring the optical characteristics of ice crystal particles.In this study,a new nonspherical and inhomogeneous ice crystal particle model is built based on the melting process of ice crystal particles.The single-scattering characteristics of ice crystal particles with different frequencies,sizes,shapes and ice crystal content(ICC)are investigated using the discrete dipole approximation(DDA)method.The results show that the single-scattering characteristics of ice crystal particles are closely related to the equivalent radius,frequency,morphology and mixing state.The single-scattering properties of the particles change regularly with the melting process of the ice crystal particles.Specifically,in the early stage of the ice crystal particle melting process,the single-scattering characteristics of ice crystal particles change significantly.With further melting,the change in the single-scattering characteristics of ice crystal particles gradually slows down when the ICC is less than 0.5.The results also show that in the early stage of the melting process,the shape of the ice crystal particles has a huge influence on the single-scattering characteristics of the particles,and in the late stage of the melting process,the single-scattering characteristics of the ice crystal particles are basically independent of the morphology of the ice crystal nuclei.This means that the influence of the morphology of the ice crystal nuclei needs to be considered in phases when simulating the scattering characteristics of the melting ice crystal particles.In summary,the results of this study should improve our understanding of the effect of size parameter,morphology and mixing state on the millimeter-wave scattering characteristics of ice clouds during the melting process and provide a reference for the remote sensing inversion of ice cloud microphysical characteristics.展开更多
The rapid evolution of multispectral detection systems requests stealth materials capable of simultaneously delivering strong microwave absorption and suppressed nearinfrared laser reflection.This study proposes a nov...The rapid evolution of multispectral detection systems requests stealth materials capable of simultaneously delivering strong microwave absorption and suppressed nearinfrared laser reflection.This study proposes a novel rare earth(RE)doping strategy to construct a heterostructures ternary Fe_(3)O_(4)@C/REOCl(RE=Sm,Er,Dy,and Ho)through in-situ assembly-thermal reduction process.The optimized Fe_(3)O_(4)@C/REOCl demonstrates exceptional multi-spectral modulation capabilities due to the synergistic effects of multicomponent dielectric loss,magnetic loss,and RE spectral modulation.The Sm^(3+)-modified system(FCS)achieved effective absorption bandwidth of 5.41 GHz at 1.5 mm,and the Ho^(3+)-modified system(FCH)exhibited ultralow laser reflectivity of 1.86%and 1.98%at the wavelength of 1.06 and 1.55μm.This study introduces a unified framework that facilitates broadband microwave absorption(>5 GHz)and dual-band laser suppression(<2%).It establishes a universal model that can be adapted to various RE components and scalable fabrication pathways for multi-spectral stealth materials.展开更多
In this work,a series of self-activated KYb(MoO_(4))_(2) phosphors with various x at% Er^(3+) doping concentrations(x=0.5,1,3,5,8,10,15) was synthesized by the solid-state reaction method.The phase structure of the as...In this work,a series of self-activated KYb(MoO_(4))_(2) phosphors with various x at% Er^(3+) doping concentrations(x=0.5,1,3,5,8,10,15) was synthesized by the solid-state reaction method.The phase structure of the as-prepared samples was analyzed by X-ray diffraction(XRD),XRD Rietveld refinement and Fourier transform infrared(FT-IR) spectroscopy.The as-prepared samples retain the orthorhombic structure with space group of Pbcn even Er^(3+) doping concentration up to 15 at%.High-purity upconversion(UC) green emission with green to red intensity ratio of 55 is observed from the as-prepared samples upon the excitation of 980 nm semiconductor laser and the optimum doping concentration of Er^(3+) ions in the self-activated KYb(MoO_(4))_(2) host is revealed as 3 at%.The strong green UC emission is confirmed as a two-photon process based on the power-dependent UC spectra.In addition,the fluorescence intensity ratios(FIRs) of the two thermally-coupled energy levels,namely ^(2)H_(11/2) and ^(4)S_(3/2).of Er^(3+) ions were investigated in the temperature region 300-570 K to evaluate the optical temperature sensor behavior of the sample.The maximum relative sensitivity(S_(R)) is determined to be 0.0069 K^(-1) at300 K and the absolute sensitivity(S_(A)) is determined to be 0.0126 K^(-1) at 300 K.The S_(A) of self-activated KYb(MoO_(4))2:Er^(3+)is almost twice that of traditional KY(MoO_(4))2:Er^(3+)/Yb^(3+)codoping phosphor.The results demonstrate that Er^(3+) ions doped self-activated KYb(MoO_(4))2 phosphor has promising application in visible display,trademark security and optical temperature sensors.展开更多
Continuous-wave cavity ring-down spectroscopy(CW-CRDS)is an important technical means to monitor greenhouse gases in atmospheric environment.In this paper,a CW-CRDS system is built to meet the needs of atmospheric met...Continuous-wave cavity ring-down spectroscopy(CW-CRDS)is an important technical means to monitor greenhouse gases in atmospheric environment.In this paper,a CW-CRDS system is built to meet the needs of atmospheric methane monitoring.The problem of mode matching is explained from the perspective of transverse mode and longitudinal mode,and the influence of laser injection efficiency on measurement precision is further analyzed.The results of cavity ring-down time measurement show that the measurement precision is higher when the laser is coupled with the fundamental mode.In the experiment,DFB laser is used to calibrate the system with standard methane concentration,and the measurement residual is less than±4×10^(-4)μs^(-1).The methane concentration in the air is monitored in real time for two days.The results show the consistency of the concentration changes over the two days,which further demonstrates the reliability of the system for the measurement of trace methane.By analyzing the influence of mode matching,it not only assists the adjustment of the optical path,but also further improves the sensitivity of the system measurement.展开更多
In this work,p-type Co3O4 decorated n-type ZnO(Co3O4/ZnO)nanocomposite was designed with the assistance of bacterial cellulose template.Phase composition,morphology and element distribution were investigated by XRD,SE...In this work,p-type Co3O4 decorated n-type ZnO(Co3O4/ZnO)nanocomposite was designed with the assistance of bacterial cellulose template.Phase composition,morphology and element distribution were investigated by XRD,SEM,HRTEM,EDS mapping and XPS.Volatile organic compounds(VOCs)sensing measurements indicated a noticeable improvement of response and decrease of working temperature for Co3O4/ZnO sensor,in comparison with pure ZnO,i.e.,the response towards 100 ppm acetone was 63.7(at a low working temperature of 180℃),which was 26 times higher than pure ZnO(response of 2.3 at 240℃).Excellent VOCs response characteristics could be ascribed to increased surface oxygen vacancy concentration(revealed by defect characterizations),catalytic activity of Co3O4 and the special p-n heterojunction structure,and bacterial cellulose provides a facile template for designing diverse functional heterojunctions for VOCs detection and other applications.展开更多
A good quality(5 at.%Yb:GdScO_(3))single crystal of F30 mm37 mm was grown successfully by the Czochralski method.Its structure is studied by the x-ray diffraction(XRD),and its atomic coordinates are obtained by Rietve...A good quality(5 at.%Yb:GdScO_(3))single crystal of F30 mm37 mm was grown successfully by the Czochralski method.Its structure is studied by the x-ray diffraction(XRD),and its atomic coordinates are obtained by Rietveld refinement.The crystal field energy level splitting of Yb^(3+)in GdScO_(3) is determined by employing the absorption and photoluminescence spectra at 8 K.Only ^(2)F_(7/2)(4)is far from the ground state ^(2)F_(7/2)(1)by 710 cm^(-1) among the crystal field energy levels split from ^(2)F_(7/2),so it is more easier to realize the laser operation of ^(2)F_(5/2)(1)^(2)F_(7/2)(4)with wavelength 1060 nm.The spin–orbit coupling parameters and intrinsic crystal field parameters(CFPs).The intrinsic crystal field parameters¯B k(k=2,4,6)of the crystal were fitted by the superposition model.The CFPs evaluated with¯Bk and coordination factor are taken as the initial parameters to fit the crystal field energy levels of the crystal,and the crystal field parameters B_(q)^(k) are obtained finally with the root-mean-square deviation 9 cm-1.It is suggested that the ligand point charge,covalency and overlap interaction are slightly weaker than charge interpenetration and coulomb exchange interaction for Yb^(3+)in GdScO_(3).The obtained Hamiltonian parameters can be used to calculate crystal field energy levels and wave functions of Yb:GdScO_(3) to analyze the mechanism of the luminescence or laser.展开更多
A numerical simulation model of plenoptic sensor aberration wavefront detection is established to simulate and analyze the detection performance of plenoptic sensor aberration wavefront for different turbulence intens...A numerical simulation model of plenoptic sensor aberration wavefront detection is established to simulate and analyze the detection performance of plenoptic sensor aberration wavefront for different turbulence intensities.The results show that the plenoptic sensor can achieve better distortion wavefront detection,and its wavefront detection accuracy improves with turbulence intensity.The unique optical structure design of the plenoptic sensor makes it more suitable for aberration wavefront detection in strong turbulent conditions.The wavefront detection performance of the plenoptic sensor is not only related to its wavefront reconstruction algorithm but also closely related to its structural parameter settings.The influence of structural parameters on the wavefront detection accuracy of plenoptic sensors under different turbulence intensities is simulated and analyzed.The variation law of wavefront detection accuracy and structural parameters under different turbulence intensities is summarized to provide a reference for the structural design and parameter optimization of plenoptic sensors.展开更多
Single-pixel imaging(SPI)can transform 2D or 3D image data into 1D light signals,which offers promising prospects for image compression and transmission.However,during data communication these light signals in public ...Single-pixel imaging(SPI)can transform 2D or 3D image data into 1D light signals,which offers promising prospects for image compression and transmission.However,during data communication these light signals in public channels will easily draw the attention of eavesdroppers.Here,we introduce an efficient encryption method for SPI data transmission that uses the 3D Arnold transformation to directly disrupt 1D single-pixel light signals and utilizes the elliptic curve encryption algorithm for key transmission.This encryption scheme immediately employs Hadamard patterns to illuminate the scene and then utilizes the 3D Arnold transformation to permutate the 1D light signal of single-pixel detection.Then the transformation parameters serve as the secret key,while the security of key exchange is guaranteed by an elliptic curve-based key exchange mechanism.Compared with existing encryption schemes,both computer simulations and optical experiments have been conducted to demonstrate that the proposed technique not only enhances the security of encryption but also eliminates the need for complicated pattern scrambling rules.Additionally,this approach solves the problem of secure key transmission,thus ensuring the security of information and the quality of the decrypted images.展开更多
Under high relative humidity(RH)conditions,the release of volatile components(such as acetate)has a significant impact on the aerosol hygroscopicity.In this work,one surface plasmon resonance microscopy(SPRM)measureme...Under high relative humidity(RH)conditions,the release of volatile components(such as acetate)has a significant impact on the aerosol hygroscopicity.In this work,one surface plasmon resonance microscopy(SPRM)measurement system was introduced to determine the hygroscopic growth factors(GFs)of three acetate aerosols separately or mixed with glucose at different RHs.For Ca(CH_(3)COO)_(2) or Mg(CH_(3)COO)_(2) aerosols,the hygroscopic growth trend of each time was lower than that of the previous time in three cyclic humidification from 70% RH to 90% RH,which may be due to the volatility of acetic acid leading to the formation of insoluble hydroxide(Ca(OH)_(2) or Mg(OH)_(2))under high RH conditions.Then the third calculated GF(using the Zdanovskii-Stokes-Robinson method)for Ca(CH_(3)COO)_(2) or Mg(CH_(3)COO)_(2) in bicomponent aerosols with 1:1 mass ratio were 3.20% or 5.33% lower than that of the first calculated GF at 90% RH.The calculated results also showed that the hygroscopicity change of bicomponent aerosol was negatively correlated with glucose content,especially when the mass ratio of Mg(CH_(3)COO)_(2) to glucose was 1:2,the GF at 90% RH only decreased by4.67% after three cyclic humidification.Inductively coupled plasma atomic emission spectrum(ICP-AES)based measurements also indicated that the changes of Mg^(2+)concentration in bicomponent was lower than that of the single-component.The results of this study reveal thatduring the efflorescence transitions of atmospheric nanoparticles,the organic acids diffusion rate may be inhibited by the coating effect of neutral organic components,and the particles aging cycle will be prolonged.展开更多
This paper discussed the main parameters contributing to the measurement uncertainty of interferometric distance meter （IDM）. A simple and robust set-up is used to measure distance of about 12 cm with an expanded un...This paper discussed the main parameters contributing to the measurement uncertainty of interferometric distance meter （IDM）. A simple and robust set-up is used to measure distance of about 12 cm with an expanded uncertainty （ k = 2） of ±16.4 μm. The measurement uncertainty is found to be limited by the wavelength measurement accuracy. This set-up can be used to measure distances up to 56 m. It also enables easy determination of the point of equal path difference between the measuring and the reference arms. LabVIEW program is used for counting of the fringes and applying fast Fourier transfor- mation （FFT） to perform frequency selective filtration to the noise. Although the reported uncertainty does not represent the state-of-art uncertainty reached for similar distance, the measurement provides traceable measurement to the unit of length, the meter.展开更多
Cylindrical density depressions generated by femtosecond laser pulses filamenting in air for different energy depositions are investigated numerically, by using a set of hydrodynamic equations. The evolution of densit...Cylindrical density depressions generated by femtosecond laser pulses filamenting in air for different energy depositions are investigated numerically, by using a set of hydrodynamic equations. The evolution of density profile is calculated for different temperature elevations. The results indicate that the gas density hole is getting shallower and wider with the increasing temperature elevations. A simulation of the propagation inside low-density channel implies a new way to generate a type of bottle beam.展开更多
Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)(PEDOT:PSS)has been widely adopted as hole transport material(HTM)in inverted perovskite solar cells(PSCs),due to high optical transparency,good mechanical flexib...Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)(PEDOT:PSS)has been widely adopted as hole transport material(HTM)in inverted perovskite solar cells(PSCs),due to high optical transparency,good mechanical flexibility,and high thermal stability;however,its acidity and hygroscopicity inevitably hamper the long-term stability of the PSCs and its energy level does not match well with perovskite materials with a relatively low open-circuit voltage.In this work,p-type delafossite CuCrO_(2)nanoparticles synthesized through hydrothermal method was employed as an alternative HTM for triple cation perovskite[(FAPbI_(3))_(0.87)(MAPbBr_(3))_(0.13)]_(0.92)(CsPbI_(3))_(0.08)(possessing better photovoltaic performance and stability than conventional CH3NH3PbI3)based inverted PSCs.The average open-circuit voltage of PSCs increases from 908 mV of the devices with PEDOT:PSS HTM to 1020 m V of the devices with CuCrO_(2)HTM.Ultraviolet photoemission spectroscopy demonstrates the energy band alignment between CuCrO_(2)and perovskite is better than that between PEDOT:PSS and perovskite,the electrochemical impedance spectroscopy indicates CuCrO_(2)-based PSCs exhibit larger recombination resistance and longer charge carrier lifetime than PEDOT:PSS-based PSCs,which contributes to the high VOCof CuCrO_(2)HTM-based PSCs.展开更多
PtTe_(2),as a two-dimensional(2D)material with unique physicochemical properties,has become a key research object that researchers focus on.In this paper,the PtTe_(2)thin film photodetectors are fabricated through the...PtTe_(2),as a two-dimensional(2D)material with unique physicochemical properties,has become a key research object that researchers focus on.In this paper,the PtTe_(2)thin film photodetectors are fabricated through the chemical vapor deposition technique.The surface morphology of the PtTe_(2)thin films is uniform,and the films can be densely packed,effectively reducing the electronic defects and carrier scattering,which can improve the photoelectric conversion process,the response speed,and the sensitivity.The PtTe_(2)device demonstrates a broadband spectral response spanning from ultraviolet(UV)to near-infrared(NIR)wavelengths.Under irradiation with lasers at 375,532,and 808 nm,the 6.9 nm thin film PtTe_(2)device exhibits a positive photoconductivity phenomenon.The photoresponsivity,specific detectivity,and the device's response time for a single cycle under the 375 nm laser irradiation were found to be 2.39 A/W,4.01×10^(10)Jones,and 0.21/0.20 s,respectively.Furthermore,a single-site scanning imaging system using a PtTe_(2)photodetector has been developed.High-resolution images of three characters,"U,""J,"and"S,"have been successfully achieved under 532 nm laser radiation.This work provides valuable experience for the application of the 2D material PtTe_(2)in the fields of optical detection,optical sensing,and optical communication.展开更多
基金supported by Independent Innovation Science Foundation of National University of Defense Technology(Grant No.23-ZZCX-JDZ-44)。
文摘Tunable mid-infrared and far-infrared laser output was demonstrated based on BaGa_(4)Se_(7)crystals and an optical parametric oscillator(OPO).With a 1.06μm Nd:YAG laser and a double-pass singly resonant OPO cavity,a laser energy output of 2.2 mJ at 10μm was obtained.By tuning the angle and temperature,a tunable laser output covering the wavelength range from 6μm to 17μm was obtained with a tuning precision better than 3 nm.The corresponding optical-to-optical conversion efficiency was 2.8%,and the slope efficiency was 4.4%.The damage effect of the output laser on detectors was also investigated,and point damage to the detector occurred at an output energy of 16.4μJ.The laser system has the advantages of miniaturization,a wide tuning range,high energy and high tuning resolution.Its broadband laser characteristics make it highly valuable for applications in atmospheric detection,infrared spectroscopy and electro-optical countermeasures.
基金the National Natural Science Foundation of China(52102012)Natural Science Foundation of Anhui Province(2208085QF217)the Fundamental Research Funds for the Central Universities(WK5290000004)。
文摘We demonstrate the growth,thermal,spectroscopy and laser performance of an Er3+doped Gdo.iYo.9AlO3(Er:GYAP)disorder crystal grown by Czochralski method.The crystal with space group Pbnm and lattice parameters of a=0.5185 nm,b=0.5327 nm,c=0.7378 nm,α=β=90°and V=0.203784 nm3 are obtained by fitting powder X-ray diffraction data.The Mohr's hardnesses along three axes are 6.94,7.27,and 7.44.The thermal expansion coefficient of b axis is 4.20×10^(-6)k^(-1)and the density is 5.88 g/cm3.The thermal conductivities are characterized as K_(a)=6.24,K_(b)=5.57,and K_(c)=6.83 W/(m·K).Meanwhile,the refractive index,absorption and emission spectra in triaxial di-rections are determined.Besides,level lifetimes of 4l11/2 and 413/2 are 0.86 and 2.83 ms.Finally,the~2.7μm multiwavelength laser outputs are observed with maximum average power of 628 mW and beam quality factors M_(x)^(2)/M_(y)^(2) of 1.42/1.45.The results prove that the Er:GYAP crystal is a promising gain medium for generating mid-infrared lasers.
基金supported by the National Key Research and Development Program of China(Nos.2018YFC0213106,2018YFC0213101,2018YFC0213102,2018YFC0213103,2018YFC0213104 and 2018YFC0213105)Anhui Provincial Natural Science Foundation(No.2108085QD177)the CASHIPS Director’s Fund(No.YZJJ2021QN07)。
文摘Accurate and comprehensive knowledge of the atmospheric environment and its evolution within the coastal ocean boundary layer are necessary for understanding the sources,chemical mechanisms,and transport processes of air pollution in land,sea,and atmosphere.We present an overview of coastal ocean boundary layer detection technology and equipment in China and summarize the progress and main achievements in recent years.China has developed a series of coastal ocean boundary layer detection technologies,including Light Detection and Ranging(LIDAR),turbulent exchange analyzer,air-sea flux analyzer,stereoscopic remote sensing of air pollutants,and oceanic aerosol detection equipment to address the technical bottleneck caused by harsh environmental conditions in coastal ocean regions.Advances in these technologies and equipment have provided scientific assistance for addressing air pollution issues and understanding land-sea-atmosphere interactions over coastal ocean regions in China.In the future,routine atmospheric observations should cover the coastal ocean boundary layer of China.
基金Project supported by the Director Fund of Advanced Laser Technology Laboratory of Anhui Province,China(Grant No.20191002).
文摘Considering the atmospheric extinction and turbulence effects,we investigate the propagation performances of supercontinuum laser sources in atmospheric turbulence statistically by using the numerical simulation method,and the differences in propagation properties between the super-continuum(SC)laser and its pump laser are also analyzed.It is found that the propagation characteristics of super-continuum laser are almost similar to those of the pump laser.The degradation of source coherence degree may cause the relative beam spreading and scintillation indexes to decrease at different propagation distances or different turbulence strengths.The root-mean-square value of beam wandering is insensitive to the variation of source correlation length,and less aperture averaging occurs when the laser source becomes less coherent.Additionally,from the point of view of beam wandering,the SC laser has no advantage over the pump laser.Although the pump laser can bring about a bigger aperture average,the SC laser has a lower scintillation which may be due to the multiple wavelength homogenization effects on intensity fluctuations.This would be the most important virtue of the SC laser that can be utilized to improve the performance of laser engineering.
基金supported by the Natural Science Foundation of Anhui Province (Grant No. 2208085QF217)the National Natural Science Foundation of China (Grant No. 52102012)the Hefei Institutes of Physical Science (HFIPS) Director’s Fund (Grant No. YZJJ2022QN08)。
文摘We demonstrate a high-energy and high-power pulse laser on a xenon lamp-pumped Er:YAP crystal. The laser performance and thermal focal lengths under different working frequencies are discussed. The results show that the thermal lens effect is gradually aggravated with the increase of working frequencies, and even working at 100 Hz, a single pulse energy of 234 m J can be achieved. A maximum average power of 41.5 W is achieved with a working frequency of 20 Hz and slope efficiency of 2.82%. This output power is much higher than other xenon lamp-pumped erbium laser devices.A Q-switched laser is demonstrated by using the TeO2crystal, the maximum output energies of 11.5 m J and 3.5 m J are obtained at 50 and 100 Hz, the corresponding peak powers are 93.4 k W and 17.2 kW, respectively.The laser wavelengths and beam quality factors are also characterized in the free-running and Q-switched modes. A higher pulse energy and peak power laser could be achieved further by improving the damage threshold of TeO2acousto-optical Q-switching. All the experimental results illustrate that the xenon lamp-pumped Er:YAP laser is a promising candidate for high-power and high-frequency mid-infrared laser devices.
基金supported by the Young Scientists Fund of National Natural Science Foundation of China(No.12004388)the National High Technology Research and Development Program of China(No.2021YFB3202402)+1 种基金the Key Research and Development Plan of Anhui Province(No.202104i07020009)the Collaborative Innovation Program of Hefei Science Center,CAS(No.2021HSCCIP005)。
文摘The optimal spectral excitation and acquisition scheme is explored by studying the effect of the lensto-sample distance(LTSD)on the spatial homogeneity and emission spectra of flat-top laser converging spot induced plasma.The energy distribution characteristics before and after the convergence of the laser beam with quasi flat-top intensity profile used in this study are theoretically simulated and experimentally measured.For an aspheric converging mirror with a focal length of100 mm,the LTSD(106 mm≥LTSD≥96 mm)was changed by raising the stainless-steel sample height.The plasma images acquired by ICCD show that there is air breakdown when the sample is below the focal point,and a ring-like plasma is produced when the sample is above the focal point.When the sample is located near the focal point,the plasma shape resembles a hemisphere.Since the spectral acquisition region is confined to the plasma core and the image contains all the optical information of the plasma,it has a lower relative standard deviation(RSD)than the spectral lines.When the sample surface is slightly higher than the focal plane of the lens,the converging spot has a quasi flat-top distribution,the spatial distribution of the plasma is more uniform,and the spectral signal is more stable.Simultaneously,there is little difference between the RSD of the plasma image and the laser energy.In order to further improve the stability of the spectral signal,it is necessary to expand the spectral acquisition area.
文摘Urban tree species provide various essential ecosystem services in cities,such as regulating urban temperatures,reducing noise,capturing carbon,and mitigating the urban heat island effect.The quality of these services is influenced by species diversity,tree health,and the distribution and the composition of trees.Traditionally,data on urban trees has been collected through field surveys and manual interpretation of remote sensing images.In this study,we evaluated the effectiveness of multispectral airborne laser scanning(ALS)data in classifying 24 common urban roadside tree species in Espoo,Finland.Tree crown structure information,intensity features,and spectral data were used for classification.Eight different machine learning algorithms were tested,with the extra trees(ET)algorithm performing the best,achieving an overall accuracy of 71.7%using multispectral LiDAR data.This result highlights that integrating structural and spectral information within a single framework can improve the classification accuracy.Future research will focus on identifying the most important features for species classification and developing algorithms with greater efficiency and accuracy.
基金supported by the National Key Research and Development Program of China(Grant No.2019YFA0706004)the Key Projects of Science and Technology Research of Henan Province(Grant No.222102320087)the Key Scientific Research Project of Colleges and Universities in Henan Province(Grant No.25B170004).
文摘The melting process of ice crystal particles has a significant effect on weather forecasting and global climate.Millimeter waveband is an excellent frequency range for exploring the optical characteristics of ice crystal particles.In this study,a new nonspherical and inhomogeneous ice crystal particle model is built based on the melting process of ice crystal particles.The single-scattering characteristics of ice crystal particles with different frequencies,sizes,shapes and ice crystal content(ICC)are investigated using the discrete dipole approximation(DDA)method.The results show that the single-scattering characteristics of ice crystal particles are closely related to the equivalent radius,frequency,morphology and mixing state.The single-scattering properties of the particles change regularly with the melting process of the ice crystal particles.Specifically,in the early stage of the ice crystal particle melting process,the single-scattering characteristics of ice crystal particles change significantly.With further melting,the change in the single-scattering characteristics of ice crystal particles gradually slows down when the ICC is less than 0.5.The results also show that in the early stage of the melting process,the shape of the ice crystal particles has a huge influence on the single-scattering characteristics of the particles,and in the late stage of the melting process,the single-scattering characteristics of the ice crystal particles are basically independent of the morphology of the ice crystal nuclei.This means that the influence of the morphology of the ice crystal nuclei needs to be considered in phases when simulating the scattering characteristics of the melting ice crystal particles.In summary,the results of this study should improve our understanding of the effect of size parameter,morphology and mixing state on the millimeter-wave scattering characteristics of ice clouds during the melting process and provide a reference for the remote sensing inversion of ice cloud microphysical characteristics.
基金supported by the National University of Defense Technology Independent Innovation Science Fund(No.XJJC2024088)Anhui Natural Science Foundation(No.2408085QA027)Anhui Provincial Natural Science Foundation(No.RCTJ202417).
文摘The rapid evolution of multispectral detection systems requests stealth materials capable of simultaneously delivering strong microwave absorption and suppressed nearinfrared laser reflection.This study proposes a novel rare earth(RE)doping strategy to construct a heterostructures ternary Fe_(3)O_(4)@C/REOCl(RE=Sm,Er,Dy,and Ho)through in-situ assembly-thermal reduction process.The optimized Fe_(3)O_(4)@C/REOCl demonstrates exceptional multi-spectral modulation capabilities due to the synergistic effects of multicomponent dielectric loss,magnetic loss,and RE spectral modulation.The Sm^(3+)-modified system(FCS)achieved effective absorption bandwidth of 5.41 GHz at 1.5 mm,and the Ho^(3+)-modified system(FCH)exhibited ultralow laser reflectivity of 1.86%and 1.98%at the wavelength of 1.06 and 1.55μm.This study introduces a unified framework that facilitates broadband microwave absorption(>5 GHz)and dual-band laser suppression(<2%).It establishes a universal model that can be adapted to various RE components and scalable fabrication pathways for multi-spectral stealth materials.
基金supported by the National Natural Science Foundation of China (52202001)Open Project of Advanced Laser Technology Laboratory of Anhui Province (AHL2021KF07)+1 种基金Major Science and Technology of Anhui Province(202203a05020002)University Natural Science Research Project of Anhui Province (KJ2021A0388)。
文摘In this work,a series of self-activated KYb(MoO_(4))_(2) phosphors with various x at% Er^(3+) doping concentrations(x=0.5,1,3,5,8,10,15) was synthesized by the solid-state reaction method.The phase structure of the as-prepared samples was analyzed by X-ray diffraction(XRD),XRD Rietveld refinement and Fourier transform infrared(FT-IR) spectroscopy.The as-prepared samples retain the orthorhombic structure with space group of Pbcn even Er^(3+) doping concentration up to 15 at%.High-purity upconversion(UC) green emission with green to red intensity ratio of 55 is observed from the as-prepared samples upon the excitation of 980 nm semiconductor laser and the optimum doping concentration of Er^(3+) ions in the self-activated KYb(MoO_(4))_(2) host is revealed as 3 at%.The strong green UC emission is confirmed as a two-photon process based on the power-dependent UC spectra.In addition,the fluorescence intensity ratios(FIRs) of the two thermally-coupled energy levels,namely ^(2)H_(11/2) and ^(4)S_(3/2).of Er^(3+) ions were investigated in the temperature region 300-570 K to evaluate the optical temperature sensor behavior of the sample.The maximum relative sensitivity(S_(R)) is determined to be 0.0069 K^(-1) at300 K and the absolute sensitivity(S_(A)) is determined to be 0.0126 K^(-1) at 300 K.The S_(A) of self-activated KYb(MoO_(4))2:Er^(3+)is almost twice that of traditional KY(MoO_(4))2:Er^(3+)/Yb^(3+)codoping phosphor.The results demonstrate that Er^(3+) ions doped self-activated KYb(MoO_(4))2 phosphor has promising application in visible display,trademark security and optical temperature sensors.
基金This research is financial supported by the Natural National Science Foundation of China(Grant Nos.11874364,41877311,and 42005107)the National Key Research and Development Program of China(Grant No.2017YFC0805004)the CAS&Bengbu Technology Transfer Project(Grant No.ZKBB202102).
文摘Continuous-wave cavity ring-down spectroscopy(CW-CRDS)is an important technical means to monitor greenhouse gases in atmospheric environment.In this paper,a CW-CRDS system is built to meet the needs of atmospheric methane monitoring.The problem of mode matching is explained from the perspective of transverse mode and longitudinal mode,and the influence of laser injection efficiency on measurement precision is further analyzed.The results of cavity ring-down time measurement show that the measurement precision is higher when the laser is coupled with the fundamental mode.In the experiment,DFB laser is used to calibrate the system with standard methane concentration,and the measurement residual is less than±4×10^(-4)μs^(-1).The methane concentration in the air is monitored in real time for two days.The results show the consistency of the concentration changes over the two days,which further demonstrates the reliability of the system for the measurement of trace methane.By analyzing the influence of mode matching,it not only assists the adjustment of the optical path,but also further improves the sensitivity of the system measurement.
文摘In this work,p-type Co3O4 decorated n-type ZnO(Co3O4/ZnO)nanocomposite was designed with the assistance of bacterial cellulose template.Phase composition,morphology and element distribution were investigated by XRD,SEM,HRTEM,EDS mapping and XPS.Volatile organic compounds(VOCs)sensing measurements indicated a noticeable improvement of response and decrease of working temperature for Co3O4/ZnO sensor,in comparison with pure ZnO,i.e.,the response towards 100 ppm acetone was 63.7(at a low working temperature of 180℃),which was 26 times higher than pure ZnO(response of 2.3 at 240℃).Excellent VOCs response characteristics could be ascribed to increased surface oxygen vacancy concentration(revealed by defect characterizations),catalytic activity of Co3O4 and the special p-n heterojunction structure,and bacterial cellulose provides a facile template for designing diverse functional heterojunctions for VOCs detection and other applications.
基金supported by the National Key Research and Development Program of China(Grant Nos.2022YFB3605700 and 2023YFB3507403)the National Natural Science Foundation of China(Grant No.52272011)+2 种基金the Youth Innovation Promotion Association of CAS(Grant No.2023463)Plan for Anhui Major Provincial Science&Technology Project(Grant No.202203a05020002)Open Project of Advanced Laser Technology Laboratory of Anhui Province(Grant No.AHL20220ZR04).
文摘A good quality(5 at.%Yb:GdScO_(3))single crystal of F30 mm37 mm was grown successfully by the Czochralski method.Its structure is studied by the x-ray diffraction(XRD),and its atomic coordinates are obtained by Rietveld refinement.The crystal field energy level splitting of Yb^(3+)in GdScO_(3) is determined by employing the absorption and photoluminescence spectra at 8 K.Only ^(2)F_(7/2)(4)is far from the ground state ^(2)F_(7/2)(1)by 710 cm^(-1) among the crystal field energy levels split from ^(2)F_(7/2),so it is more easier to realize the laser operation of ^(2)F_(5/2)(1)^(2)F_(7/2)(4)with wavelength 1060 nm.The spin–orbit coupling parameters and intrinsic crystal field parameters(CFPs).The intrinsic crystal field parameters¯B k(k=2,4,6)of the crystal were fitted by the superposition model.The CFPs evaluated with¯Bk and coordination factor are taken as the initial parameters to fit the crystal field energy levels of the crystal,and the crystal field parameters B_(q)^(k) are obtained finally with the root-mean-square deviation 9 cm-1.It is suggested that the ligand point charge,covalency and overlap interaction are slightly weaker than charge interpenetration and coulomb exchange interaction for Yb^(3+)in GdScO_(3).The obtained Hamiltonian parameters can be used to calculate crystal field energy levels and wave functions of Yb:GdScO_(3) to analyze the mechanism of the luminescence or laser.
基金the National Natural Science Foundation of China(No.61605223)the Strategic Priority Research Program of Chinese Academy of Sciences(No.614A010717)the Director Fund of Advanced Laser Technology Laboratory of Anhui Province(No.AHL2021ZR06)。
文摘A numerical simulation model of plenoptic sensor aberration wavefront detection is established to simulate and analyze the detection performance of plenoptic sensor aberration wavefront for different turbulence intensities.The results show that the plenoptic sensor can achieve better distortion wavefront detection,and its wavefront detection accuracy improves with turbulence intensity.The unique optical structure design of the plenoptic sensor makes it more suitable for aberration wavefront detection in strong turbulent conditions.The wavefront detection performance of the plenoptic sensor is not only related to its wavefront reconstruction algorithm but also closely related to its structural parameter settings.The influence of structural parameters on the wavefront detection accuracy of plenoptic sensors under different turbulence intensities is simulated and analyzed.The variation law of wavefront detection accuracy and structural parameters under different turbulence intensities is summarized to provide a reference for the structural design and parameter optimization of plenoptic sensors.
基金Project supported by the National Natural Science Foundation of China(Grant No.62075241).
文摘Single-pixel imaging(SPI)can transform 2D or 3D image data into 1D light signals,which offers promising prospects for image compression and transmission.However,during data communication these light signals in public channels will easily draw the attention of eavesdroppers.Here,we introduce an efficient encryption method for SPI data transmission that uses the 3D Arnold transformation to directly disrupt 1D single-pixel light signals and utilizes the elliptic curve encryption algorithm for key transmission.This encryption scheme immediately employs Hadamard patterns to illuminate the scene and then utilizes the 3D Arnold transformation to permutate the 1D light signal of single-pixel detection.Then the transformation parameters serve as the secret key,while the security of key exchange is guaranteed by an elliptic curve-based key exchange mechanism.Compared with existing encryption schemes,both computer simulations and optical experiments have been conducted to demonstrate that the proposed technique not only enhances the security of encryption but also eliminates the need for complicated pattern scrambling rules.Additionally,this approach solves the problem of secure key transmission,thus ensuring the security of information and the quality of the decrypted images.
基金supported by the National Natural Science Foundation of China(Nos.41905028,91544218,12134013,and 62127818)the National Key Researchand Development Program of China(No.2017YFC0209504)+3 种基金Anhui Provincial Natural Science Foundation(Nos.1908085MD114 and 2108085MD139)the Hefei Municipal Natural Science Foundation(No.2021007)the Key Research&Development program of Anhui Province(No.202104a05020010)the HFIPS Director’s Fund(Nos.YZJJ2022QN04 and BJPY2021A04)。
文摘Under high relative humidity(RH)conditions,the release of volatile components(such as acetate)has a significant impact on the aerosol hygroscopicity.In this work,one surface plasmon resonance microscopy(SPRM)measurement system was introduced to determine the hygroscopic growth factors(GFs)of three acetate aerosols separately or mixed with glucose at different RHs.For Ca(CH_(3)COO)_(2) or Mg(CH_(3)COO)_(2) aerosols,the hygroscopic growth trend of each time was lower than that of the previous time in three cyclic humidification from 70% RH to 90% RH,which may be due to the volatility of acetic acid leading to the formation of insoluble hydroxide(Ca(OH)_(2) or Mg(OH)_(2))under high RH conditions.Then the third calculated GF(using the Zdanovskii-Stokes-Robinson method)for Ca(CH_(3)COO)_(2) or Mg(CH_(3)COO)_(2) in bicomponent aerosols with 1:1 mass ratio were 3.20% or 5.33% lower than that of the first calculated GF at 90% RH.The calculated results also showed that the hygroscopicity change of bicomponent aerosol was negatively correlated with glucose content,especially when the mass ratio of Mg(CH_(3)COO)_(2) to glucose was 1:2,the GF at 90% RH only decreased by4.67% after three cyclic humidification.Inductively coupled plasma atomic emission spectrum(ICP-AES)based measurements also indicated that the changes of Mg^(2+)concentration in bicomponent was lower than that of the single-component.The results of this study reveal thatduring the efflorescence transitions of atmospheric nanoparticles,the organic acids diffusion rate may be inhibited by the coating effect of neutral organic components,and the particles aging cycle will be prolonged.
文摘This paper discussed the main parameters contributing to the measurement uncertainty of interferometric distance meter （IDM）. A simple and robust set-up is used to measure distance of about 12 cm with an expanded uncertainty （ k = 2） of ±16.4 μm. The measurement uncertainty is found to be limited by the wavelength measurement accuracy. This set-up can be used to measure distances up to 56 m. It also enables easy determination of the point of equal path difference between the measuring and the reference arms. LabVIEW program is used for counting of the fringes and applying fast Fourier transfor- mation （FFT） to perform frequency selective filtration to the noise. Although the reported uncertainty does not represent the state-of-art uncertainty reached for similar distance, the measurement provides traceable measurement to the unit of length, the meter.
基金the National Natural Science Foundation of China(No.61605223)the Strategic Priority Research Program of Chinese Academy of Sciences(Nos.306030105 and 614A010717)+1 种基金the Open Research Fund of State Key Laboratory of Pulsed Power Laser Technology(Nos.SKL2013KF01 and SKL2015KF03)the Dean Foundation of Hefei Institutes of Physical Science,Chinese Academy of Sciences(No.YZJJ201506).
文摘Cylindrical density depressions generated by femtosecond laser pulses filamenting in air for different energy depositions are investigated numerically, by using a set of hydrodynamic equations. The evolution of density profile is calculated for different temperature elevations. The results indicate that the gas density hole is getting shallower and wider with the increasing temperature elevations. A simulation of the propagation inside low-density channel implies a new way to generate a type of bottle beam.
基金jointly supported by the National Natural Science Foundation of China(No.62075223 and No.11674324)CAS Pioneer Hundred Talents Program of Chinese Academy of Sciences+5 种基金CAS-JSPS Joint Research Projects(GJHZ1891)Director Fund of Advanced Laser Technology Laboratory of Anhui Province(AHL2020ZR02)Key Lab of Photovoltaic and Energy Conservation Materials of Chinese Academy of Sciences(PECL2019QN005 and PECL2018QN001)the Natural Science Foundation of Top Talent of Shenzhen Technology University(No.2020101)Natural Science Research Project of Higher School of Anhui Province(KJ2020A0477)Initial Scientific Research Fund of Anhui Jianzhu University(No.2018QD60)。
文摘Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)(PEDOT:PSS)has been widely adopted as hole transport material(HTM)in inverted perovskite solar cells(PSCs),due to high optical transparency,good mechanical flexibility,and high thermal stability;however,its acidity and hygroscopicity inevitably hamper the long-term stability of the PSCs and its energy level does not match well with perovskite materials with a relatively low open-circuit voltage.In this work,p-type delafossite CuCrO_(2)nanoparticles synthesized through hydrothermal method was employed as an alternative HTM for triple cation perovskite[(FAPbI_(3))_(0.87)(MAPbBr_(3))_(0.13)]_(0.92)(CsPbI_(3))_(0.08)(possessing better photovoltaic performance and stability than conventional CH3NH3PbI3)based inverted PSCs.The average open-circuit voltage of PSCs increases from 908 mV of the devices with PEDOT:PSS HTM to 1020 m V of the devices with CuCrO_(2)HTM.Ultraviolet photoemission spectroscopy demonstrates the energy band alignment between CuCrO_(2)and perovskite is better than that between PEDOT:PSS and perovskite,the electrochemical impedance spectroscopy indicates CuCrO_(2)-based PSCs exhibit larger recombination resistance and longer charge carrier lifetime than PEDOT:PSS-based PSCs,which contributes to the high VOCof CuCrO_(2)HTM-based PSCs.
基金supported by the National Natural Science Foundation of China(No.12104508)the Natural Science Foundation of Jiangsu Province(Nos.BK20180862 and BK20190839)+1 种基金the China Postdoctoral Science Foundation(No.2019M651725)the Anhui Key Laboratory of Photonic Devices and Materials Science(No.AHKL2024KF01)。
文摘PtTe_(2),as a two-dimensional(2D)material with unique physicochemical properties,has become a key research object that researchers focus on.In this paper,the PtTe_(2)thin film photodetectors are fabricated through the chemical vapor deposition technique.The surface morphology of the PtTe_(2)thin films is uniform,and the films can be densely packed,effectively reducing the electronic defects and carrier scattering,which can improve the photoelectric conversion process,the response speed,and the sensitivity.The PtTe_(2)device demonstrates a broadband spectral response spanning from ultraviolet(UV)to near-infrared(NIR)wavelengths.Under irradiation with lasers at 375,532,and 808 nm,the 6.9 nm thin film PtTe_(2)device exhibits a positive photoconductivity phenomenon.The photoresponsivity,specific detectivity,and the device's response time for a single cycle under the 375 nm laser irradiation were found to be 2.39 A/W,4.01×10^(10)Jones,and 0.21/0.20 s,respectively.Furthermore,a single-site scanning imaging system using a PtTe_(2)photodetector has been developed.High-resolution images of three characters,"U,""J,"and"S,"have been successfully achieved under 532 nm laser radiation.This work provides valuable experience for the application of the 2D material PtTe_(2)in the fields of optical detection,optical sensing,and optical communication.
