Spatial light modulators,as dynamic flat-panel optical devices,have witnessed rapid development over the past two decades,concomitant with the advancements in micro-and opto-electronic integration technology.In partic...Spatial light modulators,as dynamic flat-panel optical devices,have witnessed rapid development over the past two decades,concomitant with the advancements in micro-and opto-electronic integration technology.In particular,liquid-crystal spatial light modulator(LC-SLM)technologies have been regarded as versatile tools for generating arbitrary optical fields and tailoring all degrees of freedom beyond just phase and amplitude.These devices have gained significant interest in the nascent field of structured light in space and time,facilitated by their ease of use and real-time light manipulation,fueling both fundamental research and practical applications.Here we provide an overview of the key working principles of LC-SLMs and review the significant progress made to date in their deployment for various applications,covering topics as diverse as beam shaping and steering,holography,optical trapping and tweezers,measurement,wavefront coding,optical vortex,and quantum optics.Finally,we conclude with an outlook on the potential opportunities and technical challenges in this rapidly developing field.展开更多
Plasmonic modes within metal nanostructures play a pivotal role in various nanophotonic applications.However,a significant challenge arises from the fixed shapes of nanostructures post-fabrication,resulting in limited...Plasmonic modes within metal nanostructures play a pivotal role in various nanophotonic applications.However,a significant challenge arises from the fixed shapes of nanostructures post-fabrication,resulting in limited modes under ordinary illumination.A promising solution lies in far-field control facilitated by spatial light modulators(SLMs),which enable on-site,real-time,and non-destructive manipulation of plasmon excitation.Through the robust modulation of the incident light using SLMs,this approach enables the generation,optimization,and dynamic control of surface plasmon polariton(SPP)and localized surface plasmon(LSP)modes.The versatility of this technique introduces a rich array of tunable degrees of freedom to plasmon-enhanced spectroscopy,offering novel approaches for signal optimization and functional expansion in this field.This paper provides a comprehensive review of the generation and modulation of SPP and LSP modes through far-field control with SLMs and highlights the diverse applications of this optical technology in plasmon-enhanced spectroscopy.展开更多
A lensless Vanderlugt optical correlator using two phase-only spatial light modulators （SLMs） is proposed. The SLMs are used for displaying input and filter patterns respectively. The SLMs are also used as programma...A lensless Vanderlugt optical correlator using two phase-only spatial light modulators （SLMs） is proposed. The SLMs are used for displaying input and filter patterns respectively. The SLMs are also used as programmable lenses in order to realize the lensless construction. This lensless system is simple and its alignment adjustment is easy. The performance of the SLMs as programmable lenses is also described.展开更多
Multiple quantum well spatial light modulators with 128×128 array in 38μm pitch are fabricated using two pproaches, one with an attachment of an optical substrate and another one without. These two fabrication p...Multiple quantum well spatial light modulators with 128×128 array in 38μm pitch are fabricated using two pproaches, one with an attachment of an optical substrate and another one without. These two fabrication processes are described and compared.展开更多
A simple and effective approach is proposed to minimize the effect of unmodulated light and uneven intensity caused by the pixelated structure of the spatial light modulator in a holographic display. A more uniform im...A simple and effective approach is proposed to minimize the effect of unmodulated light and uneven intensity caused by the pixelated structure of the spatial light modulator in a holographic display. A more uniform image is produced by purposely shifting the holographic images of multiple reconstructed lights with different incident angles from the zero-diffraction-order and overlapping those selected different orders. The simulation and optical experimental results show that the influence of the zero-diffraction-order can be reduced, while keeping the good uniformity of the target images by this new approach.展开更多
Steering accuracy is limited by the quantized phase modulation values and the number of phase pixels for spatial light modulators （SLMs）.Conventional methods of beam steering lack optimum precision.In this letter,a ...Steering accuracy is limited by the quantized phase modulation values and the number of phase pixels for spatial light modulators （SLMs）.Conventional methods of beam steering lack optimum precision.In this letter,a beam steering approach based on horizontally moving phase steps is proposed.Compared with the conventional methods,this novel method is able to reduce the maximum normalized steering error in SLM significantly by a factor proportional to the number of pixels.In addition,steering errors of high steering angles can be drastically reduced by a factor proportional to the product of the number of pixels and the quantized phase levels; the number of high-precision steering angles increases with the number of pixels or the quantized phase levels increasing.展开更多
A universal programmable multi-quantum-well（MQW） spatial light modulator（SLM） driving circuit is developed.With a twice scanning, it can generate programmable signals to drive a non-linear MQW SLM by using a softw...A universal programmable multi-quantum-well（MQW） spatial light modulator（SLM） driving circuit is developed.With a twice scanning, it can generate programmable signals to drive a non-linear MQW SLM by using a software preprocessing unit.By adjusting the switching network of the driving circuit, this circuit can reduce the switching noise and improve the output precision.The chip test results show that the driving voltage can swing from 0 to VDD, and its resolution could be close to 256 with a pixel area of only 65 × 65 μm2.展开更多
Our latest research results on GaAs-A1GaAs multiple quantum well spatial light modulators are presented. The thickness uniformity of the epitaxial layers across the 3-inch wafer grown by our molecular beam epitaxy is ...Our latest research results on GaAs-A1GaAs multiple quantum well spatial light modulators are presented. The thickness uniformity of the epitaxial layers across the 3-inch wafer grown by our molecular beam epitaxy is better than 0.1% and the variation of cavity resonance wavelength within the wafer is only 0.9 nm. A contrast ratio （CR） of 102 by varying bias voltage from 0 to 6.7 V is achieved after fine tuning the cavity by etching an adjust layer. Both theoretical and experimental results demonstrate that incorporating an adjust layer is an effective tuning method for obtaining high CR.展开更多
This paper describes the design and test of a novel custom driving circuit for multi-quantum-well （MQW） spatial light modulators（SLMs）.Unlike previous solutions,we integrated all blocks in one chip to synchronize ...This paper describes the design and test of a novel custom driving circuit for multi-quantum-well （MQW） spatial light modulators（SLMs）.Unlike previous solutions,we integrated all blocks in one chip to synchronize the control logic circuit and the driving circuits.Single-slope digital-to-analog converters（DACs） inside each pixel are not adopted because it is difficult to eliminate capacitor mismatch.64 column-shared 8-bit resistor-string DACs are utilized to provide programmable output voltages from 0.5 to 3.8 V.They are located on the top of 64×64 driving pixels tightly to match each other with several dummies.Each DAC performs its conversion in 280 ns and draws 80μA.For a high speed data transfer rate,the system adopts a 2-stage shift register that operates at 50 MHz and the modulating rate achieves 50 K frames/s while dissipating 302 mW from a 5-V supply.The die is fabricated in a 0.35 /μm CMOS process and its area is 5.5 x 7 mm^2.展开更多
Femtosecond laser processing is an important machining method for micro-optical components such as Fresnel zone plate(FZP).However,the low processing efficiency of the femtosecond laser restricts its application.Here,...Femtosecond laser processing is an important machining method for micro-optical components such as Fresnel zone plate(FZP).However,the low processing efficiency of the femtosecond laser restricts its application.Here,a femtosecond laser Bessel beam is proposed to process micro-FZP,which is modulated from a Gaussian beam to a Bessel annular beam.The processing time for FZP with an outer diameter of 60μm is reduced from 30 min to 1.5 min on an important semiconductor material gallium arsenide(GaAs),which significantly improves the processing efficiency.In the modulation process,a central ablation hole that has an adverse effect on the diffraction performance is produced,and the adverse effect is eliminated by superimposing the blazed grating hologram.Meanwhile,the FZP machined by spatial light modulator(SLM)has good morphology and higher diffraction efficiency,which provides a strong guarantee for the application of micro-FZP in computed tomography and solar photovoltaic cells.展开更多
Steering light into logic patterns with two-dimensional cascaded multimode waveguide is demonstrated. By employing the imaging properties of 2D multimode interference （MMI） and partial phase modulation method, the d...Steering light into logic patterns with two-dimensional cascaded multimode waveguide is demonstrated. By employing the imaging properties of 2D multimode interference （MMI） and partial phase modulation method, the design ideas and the implementing methods of the 2^（2×2） bits type spatial logic steering are discussed; therefore the structure of logical pattern is proposed. Numerical simulation is carried out to verify the design in detail by using the beam propagation method. It is expected to realize logic coders by using the integrated optical methods and exploit their potential applications in the field of optical logic.展开更多
The liquid crystal spatial light modulator （LC SLM） is very suitable for wavefront correction and optical testing and can produce a wavefront with large phase change and high accuracy. The LC SLM is composed of thou...The liquid crystal spatial light modulator （LC SLM） is very suitable for wavefront correction and optical testing and can produce a wavefront with large phase change and high accuracy. The LC SLM is composed of thousands of pixels and the pixel size and shape have effects on the diffractive characteristics of the LC SLM. This paper investigates the pixel effect on the phase of the wavefront with the scalar diffractive theory. The results show that the maximum optical path difference modulation is 41μm to produce the paraboloid wavefront with the peak to valley accuracy better than λ/10. Effects of the mismatch between the pixel and the period, and black matrix on the diffraction efficiency of the LC SLM are also analysed with the Fresnel phase lens model. The ability of the LC SLM is discussed for optical testing and wavefront correction based on the calculated results. It shows that the LC SLM can be used as a wavefront corrector and a compensator.展开更多
We report three-dimensional fluorescence emission difference(3D-FED)microscopy using a spatial light modulator(SLM).Zero phase,0–2vortex phase and binary 0-pi phase are loaded on the SLM to generate the correspondin...We report three-dimensional fluorescence emission difference(3D-FED)microscopy using a spatial light modulator(SLM).Zero phase,0–2vortex phase and binary 0-pi phase are loaded on the SLM to generate the corresponding solid,doughnut and z-axis hollow excitation spot,respectively.Our technique achieves super-resolved image by subtracting three di®erently acquired images with proper subtractive factors.Detailed theoretical analysis and simulation tests are proceeded to testify the performance of 3D-FED.Also,the improvement of lateral and axial resolution is demonstrated by imaging 100 nm°uorescent beads.The experiment yields lateral resolution of 140 nm and axial resolution of approximate 380 nm.展开更多
Liquid crystal spatial light modulator （LCSLM） realizing equal-intensity multiple beams often has some features, i.e., phase valley between two adjacent pixels, flybaek region when phase decreases immediately from 2...Liquid crystal spatial light modulator （LCSLM） realizing equal-intensity multiple beams often has some features, i.e., phase valley between two adjacent pixels, flybaek region when phase decreases immediately from 2~r to 0, and inevitable backplane curvature, which are different from those of most conventional diffractive optical elements （DOEs）, such as static DOEs. For optimal intensity uniformity, equal-intensity multi-beam generation must be considered for these artifacts. We present a tunable-grating method in which the intensity uniformity can be improved by considering the LCSLM artifacts. For instance, tuning phase modulation depth of the grating, called isosceles triangle multilevel phase grating （ITMPG）, can be used not only to improve the intensity uniformity, but also to fast steer four beams with narrow beamwidths, determined by the same effective aperture of ITMPG. Improved intensity uniformity and high relative diffraction efficiency are demonstrated through experiments with phase-only LCSLM.展开更多
A novel super-junction lateral double-diffused metal-oxide semiconductor （SJ-LDMOS） with a partial lightly doped P pillar （PD） is proposed. Firstly, the reduction in the partial P pillar charges ensures the charge...A novel super-junction lateral double-diffused metal-oxide semiconductor （SJ-LDMOS） with a partial lightly doped P pillar （PD） is proposed. Firstly, the reduction in the partial P pillar charges ensures the charge balance and suppresses the substrate-assisted depletion effect. Secondly, the new electric field peak produced by the P/P junction modulates the surface electric field distribution. Both of these result in a high breakdown voltage （BV）. In addition, due to the same conduction paths, the specific on-resistance （Ron,sp） of the PD SJ-LDMOS is approximately identical to the conventional SJ-LDMOS. Simulation results indicate that the average value of the surface lateral electric field of the PD SJ-LDMOS reaches 20 V/μm at a 15 μm drift length, resulting in a BV of 300 V.展开更多
We present a digital micromirror device（DMD） based superpixel method for focusing light through scattering media by modulating the complex field of incident light. Firstly, we numerically and experimentally investig...We present a digital micromirror device（DMD） based superpixel method for focusing light through scattering media by modulating the complex field of incident light. Firstly, we numerically and experimentally investigate focusing light through a scattering sample using the superpixel methods with different target complex fields.Then, single-point and multiple-point focusing experiments are performed using this superpixel-based complex modulation method. In our experiment, up to 71.5% relative enhancement is realized. The use of the DMDbased superpixel method for the control of the complex field of incident light opens an avenue to improve the enhancement of focusing light through scattering media.展开更多
A light field modulated imaging spectrometer （LFMIS） can acquire the spatial-spectral datacube of targets of interest or a scene in a single shot. The spectral information of a point target is imaged on the pixels c...A light field modulated imaging spectrometer （LFMIS） can acquire the spatial-spectral datacube of targets of interest or a scene in a single shot. The spectral information of a point target is imaged on the pixels covered by a microlens. The pixels receive spectral information from different spectral filters to the diffraction and misalignments of the optical components. In this paper, we present a linear spectral multiplexing model of the acquired target spectrum. A calibration method is proposed for calibrating the center wavelengths and bandwidths of channels of an LFMIS system based on the liner-variable filter （LVF） and for determining the spectral multiplexing matrix. In order to improve the accuracy of the restored spectral data, we introduce a reconstruction algorithm based on the total least square （TLS） approach. Simulation and experimental results confirm the performance of the spectrum reconstruction algorithm and validate the feasibility of the proposed calibrating scheme.展开更多
The combined use of the photoelectric and electro-optic properties of BSO crystal (Bi 12 SiO 20 ) leads to realize spatial light modulation.Under some condition,BSO crystal can become birefringent depending on...The combined use of the photoelectric and electro-optic properties of BSO crystal (Bi 12 SiO 20 ) leads to realize spatial light modulation.Under some condition,BSO crystal can become birefringent depending on a local illuminance.The relationship between the distributions of an illuminance and a birefringence will be discussed.This spatial light modulator can work in real-time. The experiment shows,in order to increase the sensitivity of BSO crystal,an electric field of 6 kV/cm at an atmosphere pressure of 15×10 5 Pa should be applied to BSO crystal.With BSO we have measured 3-dimensional deformation by means of real-time holography.展开更多
With brief statements of the linear electro-optical modulation and magnetooptical modulation, using the method of resultant of optical amplitude vectors and the methed of Jones matrix, formulas for intensity of transm...With brief statements of the linear electro-optical modulation and magnetooptical modulation, using the method of resultant of optical amplitude vectors and the methed of Jones matrix, formulas for intensity of transmitted light through the optical analyzer of various composition of electro-optical effect with magneto-optical effect are derived. The results show that the output beam from the analyzer carries information on current (or magnetic field), voltage (or electric field), active power and apparent power. When the light beam transmitted through the analyzer are transformed into electric signals, three kinds of information are included: the DC term corresponding to an active power, the term with frequency ω(50 Hz) corresponding to current or voltage, and the term with frequency 2ω(100 Hz) corresponding to an apparnt power.So, we can use the electric filter circuit to pick out the DC component for measuring active power; to pick out the component with frequency ω(50 Hz) for measuring current or voltage; and to pick out the component with frequency 2ω(100 Hz) for measuring apparent power. The paper discusses what quantities are measured when the analyzer is set on certain definite values, and ponts out the optimum selection for various measurements.展开更多
基金supports from National Natural Science Foundation of China (No.62235009).
文摘Spatial light modulators,as dynamic flat-panel optical devices,have witnessed rapid development over the past two decades,concomitant with the advancements in micro-and opto-electronic integration technology.In particular,liquid-crystal spatial light modulator(LC-SLM)technologies have been regarded as versatile tools for generating arbitrary optical fields and tailoring all degrees of freedom beyond just phase and amplitude.These devices have gained significant interest in the nascent field of structured light in space and time,facilitated by their ease of use and real-time light manipulation,fueling both fundamental research and practical applications.Here we provide an overview of the key working principles of LC-SLMs and review the significant progress made to date in their deployment for various applications,covering topics as diverse as beam shaping and steering,holography,optical trapping and tweezers,measurement,wavefront coding,optical vortex,and quantum optics.Finally,we conclude with an outlook on the potential opportunities and technical challenges in this rapidly developing field.
基金supported by the Guangdong Major Project of Basic and Applied Basic Research(Grant No.2020B0301030009)the National Key Research and Development Program of China(Grant No.2022YFA1604304)the National Natural Science Foundation of China(Grant No.92250305).
文摘Plasmonic modes within metal nanostructures play a pivotal role in various nanophotonic applications.However,a significant challenge arises from the fixed shapes of nanostructures post-fabrication,resulting in limited modes under ordinary illumination.A promising solution lies in far-field control facilitated by spatial light modulators(SLMs),which enable on-site,real-time,and non-destructive manipulation of plasmon excitation.Through the robust modulation of the incident light using SLMs,this approach enables the generation,optimization,and dynamic control of surface plasmon polariton(SPP)and localized surface plasmon(LSP)modes.The versatility of this technique introduces a rich array of tunable degrees of freedom to plasmon-enhanced spectroscopy,offering novel approaches for signal optimization and functional expansion in this field.This paper provides a comprehensive review of the generation and modulation of SPP and LSP modes through far-field control with SLMs and highlights the diverse applications of this optical technology in plasmon-enhanced spectroscopy.
文摘A lensless Vanderlugt optical correlator using two phase-only spatial light modulators （SLMs） is proposed. The SLMs are used for displaying input and filter patterns respectively. The SLMs are also used as programmable lenses in order to realize the lensless construction. This lensless system is simple and its alignment adjustment is easy. The performance of the SLMs as programmable lenses is also described.
文摘Multiple quantum well spatial light modulators with 128×128 array in 38μm pitch are fabricated using two pproaches, one with an attachment of an optical substrate and another one without. These two fabrication processes are described and compared.
基金supported by the UK Engineering and Physical Sciences Research Council(EPSRC) for the support through the EPSRC Centre for Innovative Manufacturing in Ultra Precision(EP/I033491/1)
文摘A simple and effective approach is proposed to minimize the effect of unmodulated light and uneven intensity caused by the pixelated structure of the spatial light modulator in a holographic display. A more uniform image is produced by purposely shifting the holographic images of multiple reconstructed lights with different incident angles from the zero-diffraction-order and overlapping those selected different orders. The simulation and optical experimental results show that the influence of the zero-diffraction-order can be reduced, while keeping the good uniformity of the target images by this new approach.
文摘Steering accuracy is limited by the quantized phase modulation values and the number of phase pixels for spatial light modulators （SLMs）.Conventional methods of beam steering lack optimum precision.In this letter,a beam steering approach based on horizontally moving phase steps is proposed.Compared with the conventional methods,this novel method is able to reduce the maximum normalized steering error in SLM significantly by a factor proportional to the number of pixels.In addition,steering errors of high steering angles can be drastically reduced by a factor proportional to the product of the number of pixels and the quantized phase levels; the number of high-precision steering angles increases with the number of pixels or the quantized phase levels increasing.
基金supported by the International Collaboration Plan for Science and Technology of the Chinese Ministry of Science and Technolog(No. 2008DFB10040)
文摘A universal programmable multi-quantum-well（MQW） spatial light modulator（SLM） driving circuit is developed.With a twice scanning, it can generate programmable signals to drive a non-linear MQW SLM by using a software preprocessing unit.By adjusting the switching network of the driving circuit, this circuit can reduce the switching noise and improve the output precision.The chip test results show that the driving voltage can swing from 0 to VDD, and its resolution could be close to 256 with a pixel area of only 65 × 65 μm2.
基金supported by the President Fund of CAS,the International Collaboration Plan for Science and Technology of the Chinese Ministry of Science and Technology(No.2008KR0415)the Suzhou International Cooperation Fund,China(No.SWH0809).
文摘Our latest research results on GaAs-A1GaAs multiple quantum well spatial light modulators are presented. The thickness uniformity of the epitaxial layers across the 3-inch wafer grown by our molecular beam epitaxy is better than 0.1% and the variation of cavity resonance wavelength within the wafer is only 0.9 nm. A contrast ratio （CR） of 102 by varying bias voltage from 0 to 6.7 V is achieved after fine tuning the cavity by etching an adjust layer. Both theoretical and experimental results demonstrate that incorporating an adjust layer is an effective tuning method for obtaining high CR.
文摘This paper describes the design and test of a novel custom driving circuit for multi-quantum-well （MQW） spatial light modulators（SLMs）.Unlike previous solutions,we integrated all blocks in one chip to synchronize the control logic circuit and the driving circuits.Single-slope digital-to-analog converters（DACs） inside each pixel are not adopted because it is difficult to eliminate capacitor mismatch.64 column-shared 8-bit resistor-string DACs are utilized to provide programmable output voltages from 0.5 to 3.8 V.They are located on the top of 64×64 driving pixels tightly to match each other with several dummies.Each DAC performs its conversion in 280 ns and draws 80μA.For a high speed data transfer rate,the system adopts a 2-stage shift register that operates at 50 MHz and the modulating rate achieves 50 K frames/s while dissipating 302 mW from a 5-V supply.The die is fabricated in a 0.35 /μm CMOS process and its area is 5.5 x 7 mm^2.
基金Projects(51875584,51875585,51975590)supported by the National Natural Science Foundation of China。
文摘Femtosecond laser processing is an important machining method for micro-optical components such as Fresnel zone plate(FZP).However,the low processing efficiency of the femtosecond laser restricts its application.Here,a femtosecond laser Bessel beam is proposed to process micro-FZP,which is modulated from a Gaussian beam to a Bessel annular beam.The processing time for FZP with an outer diameter of 60μm is reduced from 30 min to 1.5 min on an important semiconductor material gallium arsenide(GaAs),which significantly improves the processing efficiency.In the modulation process,a central ablation hole that has an adverse effect on the diffraction performance is produced,and the adverse effect is eliminated by superimposing the blazed grating hologram.Meanwhile,the FZP machined by spatial light modulator(SLM)has good morphology and higher diffraction efficiency,which provides a strong guarantee for the application of micro-FZP in computed tomography and solar photovoltaic cells.
基金Project supported by the National Natural Science Foundation of China （Grant No 60477018） and the Major Program of the National Natural Science Foundation of China （Grant No 60436020）.
文摘Steering light into logic patterns with two-dimensional cascaded multimode waveguide is demonstrated. By employing the imaging properties of 2D multimode interference （MMI） and partial phase modulation method, the design ideas and the implementing methods of the 2^（2×2） bits type spatial logic steering are discussed; therefore the structure of logical pattern is proposed. Numerical simulation is carried out to verify the design in detail by using the beam propagation method. It is expected to realize logic coders by using the integrated optical methods and exploit their potential applications in the field of optical logic.
基金Project supported by the National Natural Science Foundation of China （Nos 60578035, 50473040） and the Science Foundation of Jilin Province （Nos 20050520, 20050321-2）.
文摘The liquid crystal spatial light modulator （LC SLM） is very suitable for wavefront correction and optical testing and can produce a wavefront with large phase change and high accuracy. The LC SLM is composed of thousands of pixels and the pixel size and shape have effects on the diffractive characteristics of the LC SLM. This paper investigates the pixel effect on the phase of the wavefront with the scalar diffractive theory. The results show that the maximum optical path difference modulation is 41μm to produce the paraboloid wavefront with the peak to valley accuracy better than λ/10. Effects of the mismatch between the pixel and the period, and black matrix on the diffraction efficiency of the LC SLM are also analysed with the Fresnel phase lens model. The ability of the LC SLM is discussed for optical testing and wavefront correction based on the calculated results. It shows that the LC SLM can be used as a wavefront corrector and a compensator.
基金This work was financially supported by grants from the National Basic Research Program of China (973 Program)(No.2015CB352003)the National Natural Science Foundation of China (Nos.61377013,61335003,61378051,and 61427818)+1 种基金NSFC of Zhejiang province LR16F050001,Innovation Joint Research Center for iCPS (2015XZZX005-01)Open Foundation of the State Key Laboratory of Modern Optical Instrumentation.
文摘We report three-dimensional fluorescence emission difference(3D-FED)microscopy using a spatial light modulator(SLM).Zero phase,0–2vortex phase and binary 0-pi phase are loaded on the SLM to generate the corresponding solid,doughnut and z-axis hollow excitation spot,respectively.Our technique achieves super-resolved image by subtracting three di®erently acquired images with proper subtractive factors.Detailed theoretical analysis and simulation tests are proceeded to testify the performance of 3D-FED.Also,the improvement of lateral and axial resolution is demonstrated by imaging 100 nm°uorescent beads.The experiment yields lateral resolution of 140 nm and axial resolution of approximate 380 nm.
基金supported by the National Natural Science Foundation of China (Grant No. 60878048)the China Postdoctoral Science Foundation (Grant No. 20080440898)
文摘Liquid crystal spatial light modulator （LCSLM） realizing equal-intensity multiple beams often has some features, i.e., phase valley between two adjacent pixels, flybaek region when phase decreases immediately from 2~r to 0, and inevitable backplane curvature, which are different from those of most conventional diffractive optical elements （DOEs）, such as static DOEs. For optimal intensity uniformity, equal-intensity multi-beam generation must be considered for these artifacts. We present a tunable-grating method in which the intensity uniformity can be improved by considering the LCSLM artifacts. For instance, tuning phase modulation depth of the grating, called isosceles triangle multilevel phase grating （ITMPG）, can be used not only to improve the intensity uniformity, but also to fast steer four beams with narrow beamwidths, determined by the same effective aperture of ITMPG. Improved intensity uniformity and high relative diffraction efficiency are demonstrated through experiments with phase-only LCSLM.
基金supported by the National Science and Technology Major Project of the Ministry of Science and Technology of China (Grant No. 2010ZX02201)the National Natural Science Foundation of China (Grant No. 61176069)the National Defense Pre-Research of China (Grant No. 51308020304)
文摘A novel super-junction lateral double-diffused metal-oxide semiconductor （SJ-LDMOS） with a partial lightly doped P pillar （PD） is proposed. Firstly, the reduction in the partial P pillar charges ensures the charge balance and suppresses the substrate-assisted depletion effect. Secondly, the new electric field peak produced by the P/P junction modulates the surface electric field distribution. Both of these result in a high breakdown voltage （BV）. In addition, due to the same conduction paths, the specific on-resistance （Ron,sp） of the PD SJ-LDMOS is approximately identical to the conventional SJ-LDMOS. Simulation results indicate that the average value of the surface lateral electric field of the PD SJ-LDMOS reaches 20 V/μm at a 15 μm drift length, resulting in a BV of 300 V.
基金Supported by the Natural Science Foundation of Beijing under Grant Nos 2162033 and 7182091the National Natural Science Foundation of China under Grant No 21627813
文摘We present a digital micromirror device（DMD） based superpixel method for focusing light through scattering media by modulating the complex field of incident light. Firstly, we numerically and experimentally investigate focusing light through a scattering sample using the superpixel methods with different target complex fields.Then, single-point and multiple-point focusing experiments are performed using this superpixel-based complex modulation method. In our experiment, up to 71.5% relative enhancement is realized. The use of the DMDbased superpixel method for the control of the complex field of incident light opens an avenue to improve the enhancement of focusing light through scattering media.
基金Project supported by the National Natural Science Foundation of China(Grant No.61307020)Beijing Natural Science Foundation(Grant No.4172038)the Qingdao Opto-electronic United Foundation,China
文摘A light field modulated imaging spectrometer （LFMIS） can acquire the spatial-spectral datacube of targets of interest or a scene in a single shot. The spectral information of a point target is imaged on the pixels covered by a microlens. The pixels receive spectral information from different spectral filters to the diffraction and misalignments of the optical components. In this paper, we present a linear spectral multiplexing model of the acquired target spectrum. A calibration method is proposed for calibrating the center wavelengths and bandwidths of channels of an LFMIS system based on the liner-variable filter （LVF） and for determining the spectral multiplexing matrix. In order to improve the accuracy of the restored spectral data, we introduce a reconstruction algorithm based on the total least square （TLS） approach. Simulation and experimental results confirm the performance of the spectrum reconstruction algorithm and validate the feasibility of the proposed calibrating scheme.
文摘The combined use of the photoelectric and electro-optic properties of BSO crystal (Bi 12 SiO 20 ) leads to realize spatial light modulation.Under some condition,BSO crystal can become birefringent depending on a local illuminance.The relationship between the distributions of an illuminance and a birefringence will be discussed.This spatial light modulator can work in real-time. The experiment shows,in order to increase the sensitivity of BSO crystal,an electric field of 6 kV/cm at an atmosphere pressure of 15×10 5 Pa should be applied to BSO crystal.With BSO we have measured 3-dimensional deformation by means of real-time holography.
文摘The liquid crystal television spatial light modulator (LCTVSLM) characterized is usable in optical processing applications,e.g.,optical pattern recognition,associative memory, optical computing,correlation detection and optical data processing systems.The array performance and real-time optical correlation applications are reviewed.
文摘With brief statements of the linear electro-optical modulation and magnetooptical modulation, using the method of resultant of optical amplitude vectors and the methed of Jones matrix, formulas for intensity of transmitted light through the optical analyzer of various composition of electro-optical effect with magneto-optical effect are derived. The results show that the output beam from the analyzer carries information on current (or magnetic field), voltage (or electric field), active power and apparent power. When the light beam transmitted through the analyzer are transformed into electric signals, three kinds of information are included: the DC term corresponding to an active power, the term with frequency ω(50 Hz) corresponding to current or voltage, and the term with frequency 2ω(100 Hz) corresponding to an apparnt power.So, we can use the electric filter circuit to pick out the DC component for measuring active power; to pick out the component with frequency ω(50 Hz) for measuring current or voltage; and to pick out the component with frequency 2ω(100 Hz) for measuring apparent power. The paper discusses what quantities are measured when the analyzer is set on certain definite values, and ponts out the optimum selection for various measurements.
