To obtain a stable amplified spontaneous emission（ASE） source for complex environment applications, we design an ASE source and study the output power and spectral characteristics under different ambient temperature...To obtain a stable amplified spontaneous emission（ASE） source for complex environment applications, we design an ASE source and study the output power and spectral characteristics under different ambient temperatures.We optimize the structure of the ASE source to flatten the ASE spectrum, and study the output characteristics in terms of output power and optical spectrum under different pump powers. Then the performance of the ASE source is investigated in the temperature range from-18.9°C to 50°C. A stable-power and flat-spectrum ASE source can be obtained by structural optimization and pump control.展开更多
The noise prediction of the turbocharger is studied.The broadband noise source model is employed to predict the near-field noise of the turbocharger.The 3D software Solidworks is adopted to establish the model blades ...The noise prediction of the turbocharger is studied.The broadband noise source model is employed to predict the near-field noise of the turbocharger.The 3D software Solidworks is adopted to establish the model blades and inlet of turbocharger compressor,then this 3D model is introduced into the software CFD to calculate the flow-field under different inlet shapes,different blades shapes and different clearances between casing and impeller.On the base of the above simulation,the broadband noise source model is employed to calculate and analyze the near-field noise.The calculation shows that compressor static pressure values and the sound power values near the impeller outlet are the largest.Through the noise calculation by using broadband noise source model under different inlet shapes and blade shapes,we find that the noise level of the inlet of cylindrical and cone types are smaller.Compared with the current widespread used backward skewed or radial blades,there is little difference of the noise value of the inlet of the forward skewed blades.展开更多
In order to acquire a broadband absorption spectrum in a single shot,a compact radiation source was developed by using a Z-pinch type electric discharge.This paper presents the mechanical and electrical construction o...In order to acquire a broadband absorption spectrum in a single shot,a compact radiation source was developed by using a Z-pinch type electric discharge.This paper presents the mechanical and electrical construction of the source,as well as its electrical and optical characteristics,including the intense continuum of radiation emitted by the source in the UV and visible spectral range.It also shows that the compactness of the source allows direct coupling with the probed medium,enabling broadband absorption measurement in the spectral range of 200e300 nm without use of an optical fiber which strongly attenuates the light in the short wavelength range.Concretely,thanks to this source,broadband spectral absorption of NO molecules around 210 nm and that of OH molecules around 310 nm were recorded in this direct coupling arrangement.Copper atom spectral absorption around 325 nm of the peripheral cold zones of an intense transient arc was also recorded.展开更多
Broadband photon pairs are highly desirable for quantum metrology,quantum sensing,and quantum communication.Such sources are usually designed through type-0 phase-matching spontaneous parametric down-conversion(SPDC)t...Broadband photon pairs are highly desirable for quantum metrology,quantum sensing,and quantum communication.Such sources are usually designed through type-0 phase-matching spontaneous parametric down-conversion(SPDC)that makes the photon pairs hard to separate in the frequency-degenerate case and thus limits their applications.In this paper,we design a broadband frequency-degenerate telecom-band photon pair source via the type-II SPDC in a dispersion-engineered thin-film lithium niobate waveguide,where the polarization modes of photon pairs are orthogonal and thus are easily separated deterministically.With a 5-mm-long waveguide,our design can achieve a bandwidth of 5.56 THz(44.8 nm),which is 8.6 times larger than that of the bulk lithium niobate,and the central wavelength can be flexibly adjusted.Our design is a promising approach towards high-quality integrated photon sources and may have wide applications in photonic quantum technologies.展开更多
A broadband gas sensing technology is reported.The measurement principle relies on Fourier transform photoacoustic spectroscopy(FT-PAS)using a differential photoacoustic cell,in which both phase modulation and amplitu...A broadband gas sensing technology is reported.The measurement principle relies on Fourier transform photoacoustic spectroscopy(FT-PAS)using a differential photoacoustic cell,in which both phase modulation and amplitude modulation are simultaneously applied to the broadband light sources.The thermal light source and supercontinuum source are employed sequentially.The performance of the FT-PAS is demonstrated by measuring the spectra of methane in the 2–10μm range and acetylene in the 1–2μm range.By leveraging the wavelength-independent nature of the photoacoustic effect,this system holds promise for comprehensive full-spectrum spectral detection.展开更多
Interests surrounding the development of on-chip nonlinear optical devices have been consistently growing in the past decades due to the tremendous applications,such as quantum photonics,all-optical communications,opt...Interests surrounding the development of on-chip nonlinear optical devices have been consistently growing in the past decades due to the tremendous applications,such as quantum photonics,all-optical communications,optical computing,on-chip metrology,and sensing.Developing efficient on-chip nonlinear optical devices to meet the requirements of those applications brings the need for new directions to improve the existing photonic approaches.Recent research has directed the field of on-chip nonlinear optics toward the hybrid integration of two-dimensional layered materials(such as graphene,transition metal dichalcogenides,and black phosphorous)with various integrated platforms.The combination of well-known photonic chip design platforms(e.g.,silicon,silicon nitride)and different two-dimensional layered materials has opened the road for more versatile and efficient structures and devices,which has the great potential to unlock numerous new possibilities.This review discusses the modeling and characterization of different hybrid photonic integration structures with two-dimensional materials,highlights the current state of the art examples,and presents an outlook for future prospects.展开更多
Virtual Shack-Hartmann wavefront sensing(vSHWS)has some significant advantages and is promising for aberration measurement in the field of biomedical optical imaging.The illumination sources used in vSHWS are almost b...Virtual Shack-Hartmann wavefront sensing(vSHWS)has some significant advantages and is promising for aberration measurement in the field of biomedical optical imaging.The illumination sources used in vSHWS are almost broadband,but are treated as monochromatic sources(only using center wavelength)in current data processing,which may cause errors.This work proposed a data processing method to take into account the multiple wavelengths of the broadband spectrum,named multiple-wavelength centroid-weighting method.Its feasibility was demonstrated through a series of simulations.A wavefront generated with a set of statistical human ocular aberrations was used as the target wavefront to evaluate the performance of the proposed and current methods.The results showed that their performance was very close when used for the symmetrical,but the wavefront error of the proposed method was much smaller than that of the current method when used for the asymmetrical spectrum,especially for the broader spectrum.These results were also validated by using 20 sets of clinical human ocular aberrations including normal and diseased eyes.The proposed method and the obtained conclusions have important implications for the application of vSHWS.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No 11504320
文摘To obtain a stable amplified spontaneous emission（ASE） source for complex environment applications, we design an ASE source and study the output power and spectral characteristics under different ambient temperatures.We optimize the structure of the ASE source to flatten the ASE spectrum, and study the output characteristics in terms of output power and optical spectrum under different pump powers. Then the performance of the ASE source is investigated in the temperature range from-18.9°C to 50°C. A stable-power and flat-spectrum ASE source can be obtained by structural optimization and pump control.
基金Sponsored by the National Natural Science Foundation of China (50875022)Research Foundation of Beijing Institute of Technology(20070342012)
文摘The noise prediction of the turbocharger is studied.The broadband noise source model is employed to predict the near-field noise of the turbocharger.The 3D software Solidworks is adopted to establish the model blades and inlet of turbocharger compressor,then this 3D model is introduced into the software CFD to calculate the flow-field under different inlet shapes,different blades shapes and different clearances between casing and impeller.On the base of the above simulation,the broadband noise source model is employed to calculate and analyze the near-field noise.The calculation shows that compressor static pressure values and the sound power values near the impeller outlet are the largest.Through the noise calculation by using broadband noise source model under different inlet shapes and blade shapes,we find that the noise level of the inlet of cylindrical and cone types are smaller.Compared with the current widespread used backward skewed or radial blades,there is little difference of the noise value of the inlet of the forward skewed blades.
文摘In order to acquire a broadband absorption spectrum in a single shot,a compact radiation source was developed by using a Z-pinch type electric discharge.This paper presents the mechanical and electrical construction of the source,as well as its electrical and optical characteristics,including the intense continuum of radiation emitted by the source in the UV and visible spectral range.It also shows that the compactness of the source allows direct coupling with the probed medium,enabling broadband absorption measurement in the spectral range of 200e300 nm without use of an optical fiber which strongly attenuates the light in the short wavelength range.Concretely,thanks to this source,broadband spectral absorption of NO molecules around 210 nm and that of OH molecules around 310 nm were recorded in this direct coupling arrangement.Copper atom spectral absorption around 325 nm of the peripheral cold zones of an intense transient arc was also recorded.
基金Project supported by the National Key Research and Development Program of China(Grant No.2019YFA0705000)Innovation Program for Quantum Science and Technology(Grant No.2021ZD0301500)+1 种基金Leading-edge Technology Program of Jiangsu Natural Science Foundation(Grant No.BK20192001)the National Natural Science Foundation of China(Grant Nos.51890861 and 11974178).
文摘Broadband photon pairs are highly desirable for quantum metrology,quantum sensing,and quantum communication.Such sources are usually designed through type-0 phase-matching spontaneous parametric down-conversion(SPDC)that makes the photon pairs hard to separate in the frequency-degenerate case and thus limits their applications.In this paper,we design a broadband frequency-degenerate telecom-band photon pair source via the type-II SPDC in a dispersion-engineered thin-film lithium niobate waveguide,where the polarization modes of photon pairs are orthogonal and thus are easily separated deterministically.With a 5-mm-long waveguide,our design can achieve a bandwidth of 5.56 THz(44.8 nm),which is 8.6 times larger than that of the bulk lithium niobate,and the central wavelength can be flexibly adjusted.Our design is a promising approach towards high-quality integrated photon sources and may have wide applications in photonic quantum technologies.
基金supported by the National Natural Science Foundation of China(NSFC)(Nos.62235010,62175137,62122045,and 62075119)Shanxi Science Fund for Distinguished Young Scholars(No.20210302121003)Shanxi Provincial Special Fund for Scientific and Technological Cooperation and Exchange(No.202304041101019)。
文摘A broadband gas sensing technology is reported.The measurement principle relies on Fourier transform photoacoustic spectroscopy(FT-PAS)using a differential photoacoustic cell,in which both phase modulation and amplitude modulation are simultaneously applied to the broadband light sources.The thermal light source and supercontinuum source are employed sequentially.The performance of the FT-PAS is demonstrated by measuring the spectra of methane in the 2–10μm range and acetylene in the 1–2μm range.By leveraging the wavelength-independent nature of the photoacoustic effect,this system holds promise for comprehensive full-spectrum spectral detection.
基金supported by Paris Saclay University within the Centre for Nanoscience and Nanotechnology(C2N)in France and Aalto University in Finland.ZS thanks fundings from the Academy of Finland(314810,333982,336144,336818,352780,353364)the Academy of Finland Flagship Programme(320167,PREIN)the EU H2020-MSCA-RISE-872049(IPN-Bio),and ERC(834742).
文摘Interests surrounding the development of on-chip nonlinear optical devices have been consistently growing in the past decades due to the tremendous applications,such as quantum photonics,all-optical communications,optical computing,on-chip metrology,and sensing.Developing efficient on-chip nonlinear optical devices to meet the requirements of those applications brings the need for new directions to improve the existing photonic approaches.Recent research has directed the field of on-chip nonlinear optics toward the hybrid integration of two-dimensional layered materials(such as graphene,transition metal dichalcogenides,and black phosphorous)with various integrated platforms.The combination of well-known photonic chip design platforms(e.g.,silicon,silicon nitride)and different two-dimensional layered materials has opened the road for more versatile and efficient structures and devices,which has the great potential to unlock numerous new possibilities.This review discusses the modeling and characterization of different hybrid photonic integration structures with two-dimensional materials,highlights the current state of the art examples,and presents an outlook for future prospects.
基金This work is supported by the National Natural Science Foundation of China(Grant No.61575205).The authors would like to thank the team of Professor Fan Lüat the Eye Hospital of Wenzhou Medical University for providing clinical human ocular aberrations.
文摘Virtual Shack-Hartmann wavefront sensing(vSHWS)has some significant advantages and is promising for aberration measurement in the field of biomedical optical imaging.The illumination sources used in vSHWS are almost broadband,but are treated as monochromatic sources(only using center wavelength)in current data processing,which may cause errors.This work proposed a data processing method to take into account the multiple wavelengths of the broadband spectrum,named multiple-wavelength centroid-weighting method.Its feasibility was demonstrated through a series of simulations.A wavefront generated with a set of statistical human ocular aberrations was used as the target wavefront to evaluate the performance of the proposed and current methods.The results showed that their performance was very close when used for the symmetrical,but the wavefront error of the proposed method was much smaller than that of the current method when used for the asymmetrical spectrum,especially for the broader spectrum.These results were also validated by using 20 sets of clinical human ocular aberrations including normal and diseased eyes.The proposed method and the obtained conclusions have important implications for the application of vSHWS.
