A coherent mid-infrared laser source,which can be tuned from 7.2 μm to 12.2 μm based on the type-Ⅰ phase-matched difference frequency generation(DFG) in an uncoated ZnGeP2(ZGP) crystal,is reported.The two pump wave...A coherent mid-infrared laser source,which can be tuned from 7.2 μm to 12.2 μm based on the type-Ⅰ phase-matched difference frequency generation(DFG) in an uncoated ZnGeP2(ZGP) crystal,is reported.The two pump waves are from a type-Ⅱ phase-matched dual-wavelength KTP optical parametric oscillator(OPO) of which the signal and idler waves are tuned during 1.85-1.96 μm(extraordinary wave) and 2.5-2.33 μm(ordinary wave),respectively.The maximum energy of the generated mid-infrared laser is 10 μJ at 9.22 μm,corresponding to the peak power of 2.2 kW.展开更多
Pr3+and Yb3+co-doped phosphate glasses are prepared to study their optical properties.Excitation and emission spectra and decay curves are used to characterize their luminescence.We demonstrate that upon excitation of...Pr3+and Yb3+co-doped phosphate glasses are prepared to study their optical properties.Excitation and emission spectra and decay curves are used to characterize their luminescence.We demonstrate that upon excitation of Pr3+ion with one high energy photon at 470 nm,two near-infrared(NIR)photons are emitted at 950-1100 nm(Yb3+:2F 5/2 →2F 7/2)through an efficient cooperative energy transfer(CET)from Pr3+to Yb3+.The maximum energy transfer efficiency(ETE)and the corresponding quantum efficiency approach up to 90.17%and 190.17%,respectively.The glass materials might find potential application for improving the efficiency of silicon-based solar cells.展开更多
A calibration board composed of 8×8 near-infrared surface-mounted diodes(NIR-SMDs)(940 nm)is designed.Meanwhile,a common binocular measurement system with the average error less than 0.1320 mm is used to obtain t...A calibration board composed of 8×8 near-infrared surface-mounted diodes(NIR-SMDs)(940 nm)is designed.Meanwhile,a common binocular measurement system with the average error less than 0.1320 mm is used to obtain the geometric information of this board.A calibration method with the designed pattern is performed to obtain the parameters of the near-infrared camera(NIRC).In the experiment,the average relative errors of focal length and principal point are 0.244%and 0.735%,respectively.The mean of image residuals is less than 0.01 pixel.The error of three-dimensional(3D)measurement is less than 0.3 mm.All those results indicate that the designed calibration board is suitable and accurate for calibrating NIRC.展开更多
The temperature characteristics of near infrared surface plasmon resonance （SPR） sensors with Kretschmann configuration are studied theoretically and experimentally. The experimental results match with the numerical...The temperature characteristics of near infrared surface plasmon resonance （SPR） sensors with Kretschmann configuration are studied theoretically and experimentally. The experimental results match with the numerical simulations in the temperature range from 10 ℃ to 40.℃. With the increase of temperature, the resonance angle for gas increases slightly, but that for aqueous solution decreases obviously. No matter the dielectric layer is gas or aqueous solution, the resonance peaks are both broadened.展开更多
Super-broadband near-infrared(NIR)emission from 1100 nm to 1600 nm is observed in Bi-doped titanate glasses at the excitation of 808 nm laser diode(LD).The effects of Bi content on the optical spectra are investigated...Super-broadband near-infrared(NIR)emission from 1100 nm to 1600 nm is observed in Bi-doped titanate glasses at the excitation of 808 nm laser diode(LD).The effects of Bi content on the optical spectra are investigated.It is also found that the Bi-related emission intensity can be enhanced by Yb3+co-doping at the excitation of 980 nm LD.It should be ascribed to the energy transfer from Yb3+to active Bi ions.The energy transfer processes are studied based on the Inokuti-Hirayama(I-H)model,and the energy transfer of electric dipole-dipole interaction is confirmed to be dominant in Bi/Yb co-doped glasses.展开更多
Gallium oxide （Ga203） films were deposited on singlecrystalline sapphire （0001） substrate by radio frequency （RF） magnetron sputtering technique in the temperature range of 300--500 ℃. The microstructure of the...Gallium oxide （Ga203） films were deposited on singlecrystalline sapphire （0001） substrate by radio frequency （RF） magnetron sputtering technique in the temperature range of 300--500 ℃. The microstructure of the fl-Ga203 films were investigated in detail using X-ray diffractometer （XRD） and scanning electron microscope （SEM）. The results show that the film prepared at 500℃ exhibits the best crystallinity with a monoclinic structure （fl-Ga203）. Structure analysis reveals a clear out-of-plane orientation offl-Ga203 （201） II A1203 （0001）. The average transmittance of these films in the visible wavelength range exceeds 90%, and the optical band gap of the films varies from 4.68 eV to 4.94 eV which were measured by an ultraviolet-visible-near infrared （UV-vis-NIR） spectrophotometer. Therefore, it is hopeful that the fl-Ga203 film can be used in the UV optoelectronic devices.展开更多
Using nanosecond pulse near-infrared and mid-infrared laser pulses as the pump source, we obtain terahertz wave sources via four-wave difference frequency mixing. From the coupled wave theory, we analyze the four-wave...Using nanosecond pulse near-infrared and mid-infrared laser pulses as the pump source, we obtain terahertz wave sources via four-wave difference frequency mixing. From the coupled wave theory, we analyze the four-wave mixing process of GaSe crystal and alkali metal vapor in detail, get the analytical expression of terahertz wave output power, and discuss the conditions for achieving phase matching. By adjusting the pump frequency, the third-order nonlinear polarization of alkali metal vapor is resonance-enhanced. This program offers a new type of high-power terahertz radiation source.展开更多
Triboelectric nanogenerator （TENG） is an efficient way to convert ambient mechanical energy into electricity to power up portable electronics. In this work, a flexible inflared electrochromical device （IR-ECD） wit...Triboelectric nanogenerator （TENG） is an efficient way to convert ambient mechanical energy into electricity to power up portable electronics. In this work, a flexible inflared electrochromical device （IR-ECD） with stable performances was assembled with a TENG for building self-powered infrared detector with tunable intensity. As driven by TENG, the electrochromic device could be operated in the mid-lR region due to the reversible electrochromic reactions. An average infrared reflectance contrast of 46% was achieved in 8-14 μm regions and as well a clear thermal image change can be observed. This work indicates that the TENG-driven infrared electrochromical device has potential for use in self-powered camouflage and tbermal control.展开更多
In complex environments,infrared camouflage within the long-wave infrared range is essential for modern defense and surveillance applications,requiring precise control over both radiative and scattering properties of ...In complex environments,infrared camouflage within the long-wave infrared range is essential for modern defense and surveillance applications,requiring precise control over both radiative and scattering properties of military targets.For practical implementation,developing surfaces that integrate dynamic emissivity control,low specular reflectance,and scalable fabrication processes remains a significant challenge.Here,a novel infrared camouflage device is proposed to simultaneously achieve low specular reflectance(<0.1)and dynamic infrared camouflage.The device seamlessly blends into backgrounds with temperatures ranging from 35°C to 45°C by tuning the emissivity of the device,which is attained by controlling the Ge2Sb2Te5 phase change.In addition,it reflects almost no surrounding thermal signals compared with the conventional low-emissivity smooth surface.The thermal camouflage remains effective and stable across observation angles ranging from 20°to 60°.This work proposes a novel approach to simultaneously reducing specular reflection and dynamic emissivity control,potentially inspiring future research and applications in multispectral camouflage and stealth technology.展开更多
We report an Er3＋-doped fluorogallate glass with good thermal and chemical stability. The low maximum phonon energy and high mid-infrared （IR） transmittance of the glass are confirmed by Raman and IR spectra, respe...We report an Er3＋-doped fluorogallate glass with good thermal and chemical stability. The low maximum phonon energy and high mid-infrared （IR） transmittance of the glass are confirmed by Raman and IR spectra, respectively. Based on Judd-Ofelt theory, intensity parameters and radiative properties are determined from the absorption and emission spectra. The proposed glass possesses a large fluorescence branching ratio β （21.71%） and a maximum stimulated emission cross-section σem of Er3＋：4 I11/2 → 4 I13/2 transition at 2.71 μm （1.04 × 10^-20 cm2）. The results indicate that it can be potentially applied in high-power 2.7 μm fiber lasers.展开更多
We demonstrate an efficiency-enhanced picosecond （ps） mid-infrared radiation via optical parametric downconversion. Based on a cascaded periodically poled MgO-doped stoiehiometric lithium tantalate crystal （MgO：sP...We demonstrate an efficiency-enhanced picosecond （ps） mid-infrared radiation via optical parametric downconversion. Based on a cascaded periodically poled MgO-doped stoiehiometric lithium tantalate crystal （MgO：sPPLT）, a tandem optical parametric oscillation-optical parametric amplification （OPO-OPA） process is achieved. Compared with a single OPO process, the conversion efficiency obtains an enhancement of 71%.展开更多
Retrieving snow surface reflectance is difficult in optical remote sensing. Hence, this letter evaluates five surface reflectance models, including the Ross-Li, Roujean, Walthall, modified Rahman and Staylor models, i...Retrieving snow surface reflectance is difficult in optical remote sensing. Hence, this letter evaluates five surface reflectance models, including the Ross-Li, Roujean, Walthall, modified Rahman and Staylor models, in terms of their capacities to capture snow reflectance signatures using ground measurements in Antarctica. The biases of all the models are less than 0.0003 in both visible and near-infrared regions. Moreover, with the exception of the Staylor model, all models have root-mean-square errors of around 0.02, indicating that they can simulate the reflectance magnitude well. The R2 performances of the Ross-Li and Roujean models are higher than those of the others, indicating that these two models can capture the angle distribution of snow surface reflectance better.展开更多
The scattering properties of ZnO nanospheres with four different particle diameters of 10, 50, 100, and 200 nm suspended in water are investigated theoretical and experimentally in the spectral range of the entire vis...The scattering properties of ZnO nanospheres with four different particle diameters of 10, 50, 100, and 200 nm suspended in water are investigated theoretical and experimentally in the spectral range of the entire visible range and part of the near-infrared region. The scattering properties of ZnO nanospheres suspended in water are described by employing three main parameters： the angular distribution of the scattering intensity I, the scattering extinction coefficient ascat, and the scattering cross section ascat. The results indicate that （i） at a certain wavelength, the angular distribution of the scattering intensity appears as an obviously forward- propagating feature, and the forward-scattering intensity is dominant gradually when the particle diameter in- creases from 10 to 200 nm, and （ii） the scattering extinction coefficient and cross section can be determined by using the measured transmittance changes of a pure water sample and a given ZnO sample; they all are shown to be dependent on the particle size and incident wavelength. The experimental results of four different scattering samples agree well with the theoretical predictions within the given wavelength range.展开更多
The steady-state stimulated Raman scattering （SRS） gain with different excitation wavelengths ranging from 400 to 1100 nm of tungstate crystals, SrWO4 and BaWO4, is systematically researched. As excitation frequency...The steady-state stimulated Raman scattering （SRS） gain with different excitation wavelengths ranging from 400 to 1100 nm of tungstate crystals, SrWO4 and BaWO4, is systematically researched. As excitation frequency is close to electronic transition frequency, molecular polarizability is not a constant, which has to be taken into account in our work. The experiment and theory agree well with each other and show that SRS gain is not only proportional to Stokes light frequency, but is also inversely proportional to biquadratic excitation frequency.展开更多
Metasurface is a new kind of 2D metamaterial that is able to manage a variety of light beam modulations through steering the phase of the scattering waves. In this work, we utilize the metasurface to manipulate the li...Metasurface is a new kind of 2D metamaterial that is able to manage a variety of light beam modulations through steering the phase of the scattering waves. In this work, we utilize the metasurface to manipulate the light beam in the mid-infrared regime. By using the metallic rod and the plate structure, the metasurface presents a high polarization conversion efficiency and a wide working bandwidth. With specially rotated metallic rods, the meta- surface can realize various light beam manipulations, such as negative reflection, beam collimation, and focusing. All of these results show that such a metasurface will have potential applications in future mid-infrared optics.展开更多
Bi-doped SiO2-Al2O3-GeO2 fiber preforms are prepared by modified chemical vapor deposition （MCVD） and solution doping process. The characteristic spectra of the preforms and fibers are experimentally investigated, a...Bi-doped SiO2-Al2O3-GeO2 fiber preforms are prepared by modified chemical vapor deposition （MCVD） and solution doping process. The characteristic spectra of the preforms and fibers are experimentally investigated, and a distinct difference in emission between the two is observed. Under 808-nm excitation, an ultra-broad near-infrared （NIR） emission with full-width at half-maximum （FWHM） of 495 nm is observed in the Bi-doped fiber. This observation, to our knowledge, is the first in this field. The NIR emission consists of two bands, which may be ascribed to the Bi0 and Bi＋ species, respectively. This Bi-doDed fiber is promising for broadband or）tical amolification and widely tunable laser.展开更多
We demonstrate the near-infrared （NIR） organic light-emitting devices （OLEDs） based on copper hexade-cafluorophthalocyanine （CuPcF16） doped into 2,2,2”-（1,3,5-benzenetriyl）tris-[1-phenyl-1H-benzimidazole] （T...We demonstrate the near-infrared （NIR） organic light-emitting devices （OLEDs） based on copper hexade-cafluorophthalocyanine （CuPcF16） doped into 2,2,2”-（1,3,5-benzenetriyl）tris-[1-phenyl-1H-benzimidazole] （TPBI）. The device structure is ITO/ NPB/ TPBI：CuPcF16/BCP/Alq3/Al. Room-temperature electro- luminescence is observed at about 1106 nm due to transitions from the first excited triplet state to the ground state （T1-S0） of CuPcF16. The result indicates that FSrster and Dexter energy transfers play a minor role in these devices, while the direct charge trapping is the dominant mechanism. The absorption spectra of CuPeF16 solution in pyridine and vacuum sublimed films on quartz have also been investigated.展开更多
High-sensitivity and broad bandwidth photo-detector devices are important for both fundamental studies and high-technology applications. Here, by using three-dimensional （3D） finite-difference time-domain simulation...High-sensitivity and broad bandwidth photo-detector devices are important for both fundamental studies and high-technology applications. Here, by using three-dimensional （3D） finite-difference time-domain simulation, we design an optimized 3D multi-layer gold nano-antenna to enhance the near-infrared （NIR） absorption of germanium nanoparticles. The key ingredient is the simultaneous presence of multiple plasmonic resonance modes with strong light-harvesting effect that encompass a broad bandwidth of germanium absorption band. The simulation results show more than two orders of magnitude enhanced absorption efficiency of gernanium around 1550 nm. The design opens up a promising way to build high-sensitivity and broad bandwidth NIR photo-detectors.展开更多
The emerging perfect-absorber metamaterials （PAMs） provide an alternative material approach for the next generation of electromagnetic detection at any frequency band of interest. One type of dual cross-shaped PAMs ...The emerging perfect-absorber metamaterials （PAMs） provide an alternative material approach for the next generation of electromagnetic detection at any frequency band of interest. One type of dual cross-shaped PAMs is developed to obtain multiplex-band spectrum absorption at mid-infrared region. Three distinct absorption peaks are attributed to the polarization sensitivity excitation of the plasmonic resonance. The charge density distributions, which are excited by resonant electromagnetic waves passing through the PAMs medium, provide insights into the observed absorption behavior. We find that the retrieved optical properties of the PAMs including permittivity and permeability are still consistent with the sum of the Drude and Lorentz type models at wavelengths ranging from 2.0 to 10.0μm. Such multiplex-band absorption properties enable the proposed PAMs a powerful tool for the direct detection of multiple molecular vibrational structures, and for multiple spectra infrared detection.展开更多
The feasibility of fenestration operation in middle ear bone with pulsed infrared laser is evaluated. Healthy male New Zealand rabbits in vivo are used in the experiment. Middle ear mastoid bone of animal model is com...The feasibility of fenestration operation in middle ear bone with pulsed infrared laser is evaluated. Healthy male New Zealand rabbits in vivo are used in the experiment. Middle ear mastoid bone of animal model is completely exposed with conventional methods, and then a pulsed CO2 laser （10.6 μm） and an Er：YAG laser （2.94 μm） are used to perform the fenestration operation. Diamond drill is also used as a control group. The total operation time and light irradiation time are recorded and the opening efficiency is assessed. The morphological changes and thermal damage around the opening window on the middle ear bone are examined. It is shown that both laser systems are suitable for the fenestration operation in middle ear bone, and this no-touch technique has a lot of benefits compared with traditional methods. The bleeding during operation has an important effect on operation time and thermal injury and needs to be controlled efficiently in further study.展开更多
基金supported by the Major State Basic Research Development Program of China (No. 2007CB310403)the National Natural Science Foundation of China (No. 60801017)Research Fund for the Doctoral Program of Higher Education (No. 20070420118)
文摘A coherent mid-infrared laser source,which can be tuned from 7.2 μm to 12.2 μm based on the type-Ⅰ phase-matched difference frequency generation(DFG) in an uncoated ZnGeP2(ZGP) crystal,is reported.The two pump waves are from a type-Ⅱ phase-matched dual-wavelength KTP optical parametric oscillator(OPO) of which the signal and idler waves are tuned during 1.85-1.96 μm(extraordinary wave) and 2.5-2.33 μm(ordinary wave),respectively.The maximum energy of the generated mid-infrared laser is 10 μJ at 9.22 μm,corresponding to the peak power of 2.2 kW.
基金supported by the National Natural Science Foundation of China(Nos.61275180,51272109and50972061)the Natural Science Foundation of Zhejiang Province(Nos.Z4110072and R4100364)+1 种基金the Opening Foundation of Zhejiang Provincial Top Key DisciplineK.C.Wong Magna Fund in Ningbo University
文摘Pr3+and Yb3+co-doped phosphate glasses are prepared to study their optical properties.Excitation and emission spectra and decay curves are used to characterize their luminescence.We demonstrate that upon excitation of Pr3+ion with one high energy photon at 470 nm,two near-infrared(NIR)photons are emitted at 950-1100 nm(Yb3+:2F 5/2 →2F 7/2)through an efficient cooperative energy transfer(CET)from Pr3+to Yb3+.The maximum energy transfer efficiency(ETE)and the corresponding quantum efficiency approach up to 90.17%and 190.17%,respectively.The glass materials might find potential application for improving the efficiency of silicon-based solar cells.
基金supported by the National Natural Science Foundation of China(No.81101130)the Fundamental Research Funds for Central Universities under the South China University of Technology(No.2012ZZ0095)the Science and Technology Program of Guangdong Province(No.2012B031800026)
文摘A calibration board composed of 8×8 near-infrared surface-mounted diodes(NIR-SMDs)(940 nm)is designed.Meanwhile,a common binocular measurement system with the average error less than 0.1320 mm is used to obtain the geometric information of this board.A calibration method with the designed pattern is performed to obtain the parameters of the near-infrared camera(NIRC).In the experiment,the average relative errors of focal length and principal point are 0.244%and 0.735%,respectively.The mean of image residuals is less than 0.01 pixel.The error of three-dimensional(3D)measurement is less than 0.3 mm.All those results indicate that the designed calibration board is suitable and accurate for calibrating NIRC.
基金supported by the National Natural Science Foundation of China(No.61177076)the Fundamental Research Funds for the Central Universities(Nos.2013-Ia-038,2013-Ia-006 and 2013-ZY-121)
文摘The temperature characteristics of near infrared surface plasmon resonance （SPR） sensors with Kretschmann configuration are studied theoretically and experimentally. The experimental results match with the numerical simulations in the temperature range from 10 ℃ to 40.℃. With the increase of temperature, the resonance angle for gas increases slightly, but that for aqueous solution decreases obviously. No matter the dielectric layer is gas or aqueous solution, the resonance peaks are both broadened.
基金supported by the National Natural Science Foundation of China(Nos.51272109and50972061)the Natural Science Foundation of Zhejiang Province(Nos.R4100364and Z4110072)+1 种基金the Natural Science Foundation of Ningbo City in Zhejiang Province(No.2012A610115)K.C.Wong Magna Fund in Ningbo University
文摘Super-broadband near-infrared(NIR)emission from 1100 nm to 1600 nm is observed in Bi-doped titanate glasses at the excitation of 808 nm laser diode(LD).The effects of Bi content on the optical spectra are investigated.It is also found that the Bi-related emission intensity can be enhanced by Yb3+co-doping at the excitation of 980 nm LD.It should be ascribed to the energy transfer from Yb3+to active Bi ions.The energy transfer processes are studied based on the Inokuti-Hirayama(I-H)model,and the energy transfer of electric dipole-dipole interaction is confirmed to be dominant in Bi/Yb co-doped glasses.
基金supported by the National Natural Science Foundation of China(Nos.61274113,61404091,61505144,51502203 and 51502204)the Opening Fund of Key Laboratory of Silicon Device Technology in Chinese Academy of Sciencesthe Tianjin Natural Science Foundation(Nos.14JCZDJC31500 and 14JCQNJC00800)
文摘Gallium oxide （Ga203） films were deposited on singlecrystalline sapphire （0001） substrate by radio frequency （RF） magnetron sputtering technique in the temperature range of 300--500 ℃. The microstructure of the fl-Ga203 films were investigated in detail using X-ray diffractometer （XRD） and scanning electron microscope （SEM）. The results show that the film prepared at 500℃ exhibits the best crystallinity with a monoclinic structure （fl-Ga203）. Structure analysis reveals a clear out-of-plane orientation offl-Ga203 （201） II A1203 （0001）. The average transmittance of these films in the visible wavelength range exceeds 90%, and the optical band gap of the films varies from 4.68 eV to 4.94 eV which were measured by an ultraviolet-visible-near infrared （UV-vis-NIR） spectrophotometer. Therefore, it is hopeful that the fl-Ga203 film can be used in the UV optoelectronic devices.
基金supported by the National Natural Science Foundation of China (No.60801017)the Tianjin Municipal Primary Application and Frontier Technology Research Plan (No.11JCYBJC01100)the Key Technology Research and Development Program of Tianjin (No.09ZCKFSF00200)
文摘Using nanosecond pulse near-infrared and mid-infrared laser pulses as the pump source, we obtain terahertz wave sources via four-wave difference frequency mixing. From the coupled wave theory, we analyze the four-wave mixing process of GaSe crystal and alkali metal vapor in detail, get the analytical expression of terahertz wave output power, and discuss the conditions for achieving phase matching. By adjusting the pump frequency, the third-order nonlinear polarization of alkali metal vapor is resonance-enhanced. This program offers a new type of high-power terahertz radiation source.
基金supported by the‘‘Thousands Talents”Program for Pioneer Researcher and his Innovation Team,the National Key Research and Development Program from Ministry of Science and Technology of China(2016YFA0202703)the National Natural Science Foundation of China(51432005)+1 种基金Hubei Technology Innovation Major Project(2016AAA030)Petro China Innovation Foundation(2015D-5006-0211)
文摘Triboelectric nanogenerator （TENG） is an efficient way to convert ambient mechanical energy into electricity to power up portable electronics. In this work, a flexible inflared electrochromical device （IR-ECD） with stable performances was assembled with a TENG for building self-powered infrared detector with tunable intensity. As driven by TENG, the electrochromic device could be operated in the mid-lR region due to the reversible electrochromic reactions. An average infrared reflectance contrast of 46% was achieved in 8-14 μm regions and as well a clear thermal image change can be observed. This work indicates that the TENG-driven infrared electrochromical device has potential for use in self-powered camouflage and tbermal control.
基金National Natural Science Foundation of China(U23A20377)Postgraduate Education Reform and Quality Improvement Project of Henan Province(YJS2024JD32)POSCO(POSCO-POSTECH-RIST Convergence Research Center)National Research Foundation of Korea(RS-2022-NR067559)。
文摘In complex environments,infrared camouflage within the long-wave infrared range is essential for modern defense and surveillance applications,requiring precise control over both radiative and scattering properties of military targets.For practical implementation,developing surfaces that integrate dynamic emissivity control,low specular reflectance,and scalable fabrication processes remains a significant challenge.Here,a novel infrared camouflage device is proposed to simultaneously achieve low specular reflectance(<0.1)and dynamic infrared camouflage.The device seamlessly blends into backgrounds with temperatures ranging from 35°C to 45°C by tuning the emissivity of the device,which is attained by controlling the Ge2Sb2Te5 phase change.In addition,it reflects almost no surrounding thermal signals compared with the conventional low-emissivity smooth surface.The thermal camouflage remains effective and stable across observation angles ranging from 20°to 60°.This work proposes a novel approach to simultaneously reducing specular reflection and dynamic emissivity control,potentially inspiring future research and applications in multispectral camouflage and stealth technology.
基金supported by the Hundred Talents Program of the Chinese Academy of Sciencesthe National Natural Science Foundation of China(Nos.61475171 and 61177083)+1 种基金the Pujiang Talent Plan(No.14PJ1409200)the Joint Research Project of Chinese Academy of Science and Japan Society for the Promotion of Science(No.GJHZ1412)
文摘We report an Er3＋-doped fluorogallate glass with good thermal and chemical stability. The low maximum phonon energy and high mid-infrared （IR） transmittance of the glass are confirmed by Raman and IR spectra, respectively. Based on Judd-Ofelt theory, intensity parameters and radiative properties are determined from the absorption and emission spectra. The proposed glass possesses a large fluorescence branching ratio β （21.71%） and a maximum stimulated emission cross-section σem of Er3＋：4 I11/2 → 4 I13/2 transition at 2.71 μm （1.04 × 10^-20 cm2）. The results indicate that it can be potentially applied in high-power 2.7 μm fiber lasers.
基金supported by the International Science and Technology Cooperation Program of China(ISTCP) (No.2014DFT50230)the National Key Scientific Instrument and Equipment Development Project (No.2011YQ030127)the National Natural Science Foundation of China(No.61405133)
文摘We demonstrate an efficiency-enhanced picosecond （ps） mid-infrared radiation via optical parametric downconversion. Based on a cascaded periodically poled MgO-doped stoiehiometric lithium tantalate crystal （MgO：sPPLT）, a tandem optical parametric oscillation-optical parametric amplification （OPO-OPA） process is achieved. Compared with a single OPO process, the conversion efficiency obtains an enhancement of 71%.
基金supported by the National "863" Program of China (No. 2009AA122101)the National Natural Science Foundation of China (Nos. 40871160and 60841006)
文摘Retrieving snow surface reflectance is difficult in optical remote sensing. Hence, this letter evaluates five surface reflectance models, including the Ross-Li, Roujean, Walthall, modified Rahman and Staylor models, in terms of their capacities to capture snow reflectance signatures using ground measurements in Antarctica. The biases of all the models are less than 0.0003 in both visible and near-infrared regions. Moreover, with the exception of the Staylor model, all models have root-mean-square errors of around 0.02, indicating that they can simulate the reflectance magnitude well. The R2 performances of the Ross-Li and Roujean models are higher than those of the others, indicating that these two models can capture the angle distribution of snow surface reflectance better.
基金supported by the National Natural Science Foundation of China(Nos.41666004,41576033,and 61465009)the Graduate Student Innovation Foundation of Jiangxi Province(No.YC2015-S331)
文摘The scattering properties of ZnO nanospheres with four different particle diameters of 10, 50, 100, and 200 nm suspended in water are investigated theoretical and experimentally in the spectral range of the entire visible range and part of the near-infrared region. The scattering properties of ZnO nanospheres suspended in water are described by employing three main parameters： the angular distribution of the scattering intensity I, the scattering extinction coefficient ascat, and the scattering cross section ascat. The results indicate that （i） at a certain wavelength, the angular distribution of the scattering intensity appears as an obviously forward- propagating feature, and the forward-scattering intensity is dominant gradually when the particle diameter in- creases from 10 to 200 nm, and （ii） the scattering extinction coefficient and cross section can be determined by using the measured transmittance changes of a pure water sample and a given ZnO sample; they all are shown to be dependent on the particle size and incident wavelength. The experimental results of four different scattering samples agree well with the theoretical predictions within the given wavelength range.
基金supported by the National Natural Science Foundation of China(No.61178060)the Program for New Century Excellent Talents in University(No.NCET-10-0552)+1 种基金the Independent Innovation Foundation of Shandong University(No.2012TS215)the Natural Science Foundation for Distinguished Young Scholar of Shandong Province(No.2012JQ18)
文摘The steady-state stimulated Raman scattering （SRS） gain with different excitation wavelengths ranging from 400 to 1100 nm of tungstate crystals, SrWO4 and BaWO4, is systematically researched. As excitation frequency is close to electronic transition frequency, molecular polarizability is not a constant, which has to be taken into account in our work. The experiment and theory agree well with each other and show that SRS gain is not only proportional to Stokes light frequency, but is also inversely proportional to biquadratic excitation frequency.
基金supported by the National "973" Program of China(No.2012CB933501)the Program of "The Invention of the China Academy of Space Technology"
文摘Metasurface is a new kind of 2D metamaterial that is able to manage a variety of light beam modulations through steering the phase of the scattering waves. In this work, we utilize the metasurface to manipulate the light beam in the mid-infrared regime. By using the metallic rod and the plate structure, the metasurface presents a high polarization conversion efficiency and a wide working bandwidth. With specially rotated metallic rods, the meta- surface can realize various light beam manipulations, such as negative reflection, beam collimation, and focusing. All of these results show that such a metasurface will have potential applications in future mid-infrared optics.
文摘Bi-doped SiO2-Al2O3-GeO2 fiber preforms are prepared by modified chemical vapor deposition （MCVD） and solution doping process. The characteristic spectra of the preforms and fibers are experimentally investigated, and a distinct difference in emission between the two is observed. Under 808-nm excitation, an ultra-broad near-infrared （NIR） emission with full-width at half-maximum （FWHM） of 495 nm is observed in the Bi-doped fiber. This observation, to our knowledge, is the first in this field. The NIR emission consists of two bands, which may be ascribed to the Bi0 and Bi＋ species, respectively. This Bi-doDed fiber is promising for broadband or）tical amolification and widely tunable laser.
基金supported by the Doctoral Foundation of Dalian University of Technology (No.3005-893327)the National Natural Science Foundation of China (No.60807009)the Young Teacher Foundation of Dalian University of Technology (No.3005-893212)
文摘We demonstrate the near-infrared （NIR） organic light-emitting devices （OLEDs） based on copper hexade-cafluorophthalocyanine （CuPcF16） doped into 2,2,2”-（1,3,5-benzenetriyl）tris-[1-phenyl-1H-benzimidazole] （TPBI）. The device structure is ITO/ NPB/ TPBI：CuPcF16/BCP/Alq3/Al. Room-temperature electro- luminescence is observed at about 1106 nm due to transitions from the first excited triplet state to the ground state （T1-S0） of CuPcF16. The result indicates that FSrster and Dexter energy transfers play a minor role in these devices, while the direct charge trapping is the dominant mechanism. The absorption spectra of CuPeF16 solution in pyridine and vacuum sublimed films on quartz have also been investigated.
基金supported by the National 973 Program of China(No.2013CB632704)the National Natural Science Foundation of China(No.11374357)
文摘High-sensitivity and broad bandwidth photo-detector devices are important for both fundamental studies and high-technology applications. Here, by using three-dimensional （3D） finite-difference time-domain simulation, we design an optimized 3D multi-layer gold nano-antenna to enhance the near-infrared （NIR） absorption of germanium nanoparticles. The key ingredient is the simultaneous presence of multiple plasmonic resonance modes with strong light-harvesting effect that encompass a broad bandwidth of germanium absorption band. The simulation results show more than two orders of magnitude enhanced absorption efficiency of gernanium around 1550 nm. The design opens up a promising way to build high-sensitivity and broad bandwidth NIR photo-detectors.
基金supported by the National Natural Science Foundation of China(No.51175436)the Aeronautical Science Foundation of China(No.2012ZC53036)+1 种基金the Northwestern Polytechnical University Foundation for Fundamental Research(No.NPU-FFR-JC200811)the 111 Projects from Chinese Ministry of Education(No.B13044)
文摘The emerging perfect-absorber metamaterials （PAMs） provide an alternative material approach for the next generation of electromagnetic detection at any frequency band of interest. One type of dual cross-shaped PAMs is developed to obtain multiplex-band spectrum absorption at mid-infrared region. Three distinct absorption peaks are attributed to the polarization sensitivity excitation of the plasmonic resonance. The charge density distributions, which are excited by resonant electromagnetic waves passing through the PAMs medium, provide insights into the observed absorption behavior. We find that the retrieved optical properties of the PAMs including permittivity and permeability are still consistent with the sum of the Drude and Lorentz type models at wavelengths ranging from 2.0 to 10.0μm. Such multiplex-band absorption properties enable the proposed PAMs a powerful tool for the direct detection of multiple molecular vibrational structures, and for multiple spectra infrared detection.
基金This work was supported partly by the National Natural Science Foundation of China(Nos.60578057 and 60878062)the Natural Science Foundation of Fujian Province(No.2008J0317)the Project WKJ2008-2-035 supported by the Science Research Foundation of Ministry of Health&United Fujian Provincial Health and Education Project for Tackling the Key Research.
文摘The feasibility of fenestration operation in middle ear bone with pulsed infrared laser is evaluated. Healthy male New Zealand rabbits in vivo are used in the experiment. Middle ear mastoid bone of animal model is completely exposed with conventional methods, and then a pulsed CO2 laser （10.6 μm） and an Er：YAG laser （2.94 μm） are used to perform the fenestration operation. Diamond drill is also used as a control group. The total operation time and light irradiation time are recorded and the opening efficiency is assessed. The morphological changes and thermal damage around the opening window on the middle ear bone are examined. It is shown that both laser systems are suitable for the fenestration operation in middle ear bone, and this no-touch technique has a lot of benefits compared with traditional methods. The bleeding during operation has an important effect on operation time and thermal injury and needs to be controlled efficiently in further study.
