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Efficient stochastic parallel gradient descent training for on-chip optical processor 被引量:1
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作者 Yuanjian Wan Xudong Liu +4 位作者 Guangze Wu Min Yang Guofeng Yan Yu Zhang Jian Wang 《Opto-Electronic Advances》 SCIE EI CAS CSCD 2024年第4期5-15,共11页
In recent years,space-division multiplexing(SDM)technology,which involves transmitting data information on multiple parallel channels for efficient capacity scaling,has been widely used in fiber and free-space optical... In recent years,space-division multiplexing(SDM)technology,which involves transmitting data information on multiple parallel channels for efficient capacity scaling,has been widely used in fiber and free-space optical communication sys-tems.To enable flexible data management and cope with the mixing between different channels,the integrated reconfig-urable optical processor is used for optical switching and mitigating the channel crosstalk.However,efficient online train-ing becomes intricate and challenging,particularly when dealing with a significant number of channels.Here we use the stochastic parallel gradient descent(SPGD)algorithm to configure the integrated optical processor,which has less com-putation than the traditional gradient descent(GD)algorithm.We design and fabricate a 6×6 on-chip optical processor on silicon platform to implement optical switching and descrambling assisted by the online training with the SPDG algorithm.Moreover,we apply the on-chip processor configured by the SPGD algorithm to optical communications for optical switching and efficiently mitigating the channel crosstalk in SDM systems.In comparison with the traditional GD al-gorithm,it is found that the SPGD algorithm features better performance especially when the scale of matrix is large,which means it has the potential to optimize large-scale optical matrix computation acceleration chips. 展开更多
关键词 optical communications optical signal processing channel descrambling optical neural network chip silicon photonics
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Multi-dimensional multiplexing optical secret sharing framework with cascaded liquid crystal holograms 被引量:3
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作者 Keyao Li Yiming Wang +6 位作者 Dapu Pi Baoli Li Haitao Luan Xinyuan Fang Peng Chen Yanqing Lu Min Gu 《Opto-Electronic Advances》 SCIE EI CAS CSCD 2024年第1期28-35,共8页
Secret sharing is a promising technology for information encryption by splitting the secret information into different shares.However,the traditional scheme suffers from information leakage in decryption process since... Secret sharing is a promising technology for information encryption by splitting the secret information into different shares.However,the traditional scheme suffers from information leakage in decryption process since the amount of available information channels is limited.Herein,we propose and demonstrate an optical secret sharing framework based on the multi-dimensional multiplexing liquid crystal(LC)holograms.The LC holograms are used as spatially separated shares to carry secret images.The polarization of the incident light and the distance between different shares are served as secret keys,which can significantly improve the information security and capacity.Besides,the decryption condition is also restricted by the applied external voltage due to the variant diffraction efficiency,which further increases the information security.In implementation,an artificial neural network(ANN)model is developed to carefully design the phase distribution of each LC hologram.With the advantage of high security,high capacity and simple configuration,our optical secret sharing framework has great potentials in optical encryption and dynamic holographic display. 展开更多
关键词 holographic encryption optical secret sharing cascaded liquid crystal hologram multi-dimensional multiplexing
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Conventional Geothermal Systems and Unconventional Geothermal Developments: An Overview 被引量:1
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作者 Maryam Khodayar Sveinbjörn Björnsson 《Open Journal of Geology》 CAS 2024年第2期196-246,共51页
This paper provides an overview of conventional geothermal systems and unconventional geothermal developments as a common reference is needed for discussions between energy professionals. Conventional geothermal syste... This paper provides an overview of conventional geothermal systems and unconventional geothermal developments as a common reference is needed for discussions between energy professionals. Conventional geothermal systems have the heat, permeability and fluid, requiring only drilling down to °C, normal heat flow or decaying radiogenic granite as heat sources, and used in district heating. Medium-temperature (MT) 100°C - 190°C, and high-temperature (HT) 190°C - 374°C resources are mostly at plate boundaries, with volcanic intrusive heat source, used mostly for electricity generation. Single well capacities are °C - 500°C) and a range of depths (1 m to 20 Km), but lack permeability or fluid, thus requiring stimulations for heat extraction by conduction. HVAC is 1 - 2 m deep and shallow geothermal down to 500 m in wells, both capturing °C, with °C are either advanced by geothermal developers at <7 Km depth (Enhanced Geothermal Systems (EGS), drilling below brittle-ductile transition zones and under geothermal fields), or by the Oil & Gas industry (Advanced Geothermal Systems, heat recovery from hydrocarbon wells or reservoirs, Superhot Rock Geothermal, and millimeter-wave drilling down to 20 Km). Their primary aim is electricity generation, relying on closed-loops, but EGS uses fractures for heat exchange with earthquake risks during fracking. Unconventional approaches could be everywhere, with shallow geothermal already functional. The deeper and hotter unconventional alternatives are still experimental, overcoming costs and technological challenges to become fully commercial. Meanwhile, the conventional geothermal resources remain the most proven opportunities for investments and development. 展开更多
关键词 Conventional Geothermal systems Unconventional Geothermal Developments Shallow and Deep Closed-Loops Enhanced Geothermal systems Supercritical and Millimeter-Wave Drilling
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Coherent optical frequency transfer via 972-km fiber link 被引量:1
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作者 邓雪 张翔 +8 位作者 臧琦 焦东东 王丹 刘杰 高静 许冠军 董瑞芳 刘涛 张首刚 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第2期277-282,共6页
We demonstrate coherent optical frequency dissemination over a distance of 972 km by cascading two spans where the phase noise is passively compensated for.Instead of employing a phase discriminator and a phase lockin... We demonstrate coherent optical frequency dissemination over a distance of 972 km by cascading two spans where the phase noise is passively compensated for.Instead of employing a phase discriminator and a phase locking loop in the conventional active phase control scheme,the passive phase noise cancellation is realized by feeding double-trip beat-note frequency to the driver of the acoustic optical modulator at the local site.This passive scheme exhibits fine robustness and reliability,making it suitable for long-distance and noisy fiber links.An optical regeneration station is used in the link for signal amplification and cascaded transmission.The phase noise cancellation and transfer instability of the 972-km link is investigated,and transfer instability of 1.1×10^(-19)at 10^(4)s is achieved.This work provides a promising method for realizing optical frequency distribution over thousands of kilometers by using fiber links. 展开更多
关键词 optical frequency transfer fiber link phase noise cancellation
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Systems Theory-Driven Framework for AI Integration into the Holistic Material Basis Research of Traditional Chinese Medicine 被引量:1
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作者 Jingqi Zeng Xiaobin Jia 《Engineering》 SCIE EI CAS CSCD 2024年第9期28-50,共23页
This paper introduces a systems theory-driven framework to integration artificial intelligence(AI)into traditional Chinese medicine(TCM)research,enhancing the understanding of TCM’s holistic material basis while adhe... This paper introduces a systems theory-driven framework to integration artificial intelligence(AI)into traditional Chinese medicine(TCM)research,enhancing the understanding of TCM’s holistic material basis while adhering to evidence-based principles.Utilizing the System Function Decoding Model(SFDM),the research progresses through define,quantify,infer,and validate phases to systematically explore TCM’s material basis.It employs a dual analytical approach that combines top-down,systems theory-guided perspectives with bottom-up,elements-structure-function methodologies,provides comprehensive insights into TCM’s holistic material basis.Moreover,the research examines AI’s role in quantitative assessment and predictive analysis of TCM’s material components,proposing two specific AIdriven technical applications.This interdisciplinary effort underscores AI’s potential to enhance our understanding of TCM’s holistic material basis and establishes a foundation for future research at the intersection of traditional wisdom and modern technology. 展开更多
关键词 Artificial intelligence systems theory Traditional Chinese medicine Material basis BOTTOM-UP
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Computational Experiments for Complex Social Systems:Experiment Design and Generative Explanation 被引量:2
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作者 Xiao Xue Deyu Zhou +5 位作者 Xiangning Yu Gang Wang Juanjuan Li Xia Xie Lizhen Cui Fei-Yue Wang 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2024年第4期1022-1038,共17页
Powered by advanced information technology,more and more complex systems are exhibiting characteristics of the cyber-physical-social systems(CPSS).In this context,computational experiments method has emerged as a nove... Powered by advanced information technology,more and more complex systems are exhibiting characteristics of the cyber-physical-social systems(CPSS).In this context,computational experiments method has emerged as a novel approach for the design,analysis,management,control,and integration of CPSS,which can realize the causal analysis of complex systems by means of“algorithmization”of“counterfactuals”.However,because CPSS involve human and social factors(e.g.,autonomy,initiative,and sociality),it is difficult for traditional design of experiment(DOE)methods to achieve the generative explanation of system emergence.To address this challenge,this paper proposes an integrated approach to the design of computational experiments,incorporating three key modules:1)Descriptive module:Determining the influencing factors and response variables of the system by means of the modeling of an artificial society;2)Interpretative module:Selecting factorial experimental design solution to identify the relationship between influencing factors and macro phenomena;3)Predictive module:Building a meta-model that is equivalent to artificial society to explore its operating laws.Finally,a case study of crowd-sourcing platforms is presented to illustrate the application process and effectiveness of the proposed approach,which can reveal the social impact of algorithmic behavior on“rider race”. 展开更多
关键词 Agent-based modeling computational experiments cyber-physical-social systems(CPSS) generative deduction generative experiments meta model
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Prescribed Performance Tracking Control of Time-Delay Nonlinear Systems With Output Constraints 被引量:1
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作者 Jin-Xi Zhang Kai-Di Xu Qing-Guo Wang 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2024年第7期1557-1565,共9页
The problem of prescribed performance tracking control for unknown time-delay nonlinear systems subject to output constraints is dealt with in this paper. In contrast with related works, only the most fundamental requ... The problem of prescribed performance tracking control for unknown time-delay nonlinear systems subject to output constraints is dealt with in this paper. In contrast with related works, only the most fundamental requirements, i.e., boundedness and the local Lipschitz condition, are assumed for the allowable time delays. Moreover, we focus on the case where the reference is unknown beforehand, which renders the standard prescribed performance control designs under output constraints infeasible. To conquer these challenges, a novel robust prescribed performance control approach is put forward in this paper.Herein, a reverse tuning function is skillfully constructed and automatically generates a performance envelop for the tracking error. In addition, a unified performance analysis framework based on proof by contradiction and the barrier function is established to reveal the inherent robustness of the control system against the time delays. It turns out that the system output tracks the reference with a preassigned settling time and good accuracy,without constraint violations. A comparative simulation on a two-stage chemical reactor is carried out to illustrate the above theoretical findings. 展开更多
关键词 Nonlinear systems output constraints prescribed performance reference tracking time delays
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Finite-time Prescribed Performance Time-Varying Formation Control for Second-Order Multi-Agent Systems With Non-Strict Feedback Based on a Neural Network Observer 被引量:1
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作者 Chi Ma Dianbiao Dong 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2024年第4期1039-1050,共12页
This paper studies the problem of time-varying formation control with finite-time prescribed performance for nonstrict feedback second-order multi-agent systems with unmeasured states and unknown nonlinearities.To eli... This paper studies the problem of time-varying formation control with finite-time prescribed performance for nonstrict feedback second-order multi-agent systems with unmeasured states and unknown nonlinearities.To eliminate nonlinearities,neural networks are applied to approximate the inherent dynamics of the system.In addition,due to the limitations of the actual working conditions,each follower agent can only obtain the locally measurable partial state information of the leader agent.To address this problem,a neural network state observer based on the leader state information is designed.Then,a finite-time prescribed performance adaptive output feedback control strategy is proposed by restricting the sliding mode surface to a prescribed region,which ensures that the closed-loop system has practical finite-time stability and that formation errors of the multi-agent systems converge to the prescribed performance bound in finite time.Finally,a numerical simulation is provided to demonstrate the practicality and effectiveness of the developed algorithm. 展开更多
关键词 Finite-time control multi-agent systems neural network prescribed performance control time-varying formation control
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Evaluation of retinal and choroidal thickness changes in overweight and obese adults without ocular symptoms by swept-source optical coherence tomography 被引量:1
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作者 Qing-Jian Li Sheng-Mei Zhou +7 位作者 Ling-Yu Zhang An-Ni Lin Yang Zhang Jing Jiang Xin Che Yi-Wen Qian Yan Liu Zhi-Liang Wang 《International Journal of Ophthalmology(English edition)》 SCIE CAS 2024年第4期707-712,共6页
AIM:To evaluate the relationship of overweight and obesity with retinal and choroidal thickness in adults without ocular symptoms by swept-source optical coherence tomography(SS-OCT).METHODS:According to the body mass... AIM:To evaluate the relationship of overweight and obesity with retinal and choroidal thickness in adults without ocular symptoms by swept-source optical coherence tomography(SS-OCT).METHODS:According to the body mass index(BMI)results,the adults enrolled in the cross-sectional study were divided into the normal group(18.50≤BMI<25.00 kg/m^(2)),the overweight group(25.00≤BMI<30.00 kg/m^(2)),and the obesity group(BMI≥30.00 kg/m^(2)).The one-way ANOVA and the Chi-square test were used for comparisons.Pearson’s correlation analysis was used to evaluate the relationships between the measured variables.RESULTS:This research covered the left eyes of 3 groups of 434 age-and sex-matched subjects each:normal,overweight,and obesity.The mean BMI was 22.20±1.67,26.82±1.38,and 32.21±2.35 kg/m^(2) in normal,overweight and obesity groups,respectively.The choroid was significantly thinner in both the overweight and obesity groups compared to the normal group(P<0.05 for all),while the retinal thickness of the three groups did not differ significantly.Pearson’s correlation analysis showed that BMI was significantly negatively correlated with choroidal thickness,but no significant correlation was observed between BMI and retinal thickness.CONCLUSION:Choroidal thickness is decreased in people with overweight or obesity.Research on changes in choroidal thickness contributes to the understanding of the mechanisms of certain ocular disorders in overweight and obese adults. 展开更多
关键词 OVERWEIGHT OBESITY body mass index choroidal thickness retinal thickness swept-source optical coherence tomography
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Influence of the initial parameters on soliton interaction in nonlinear optical systems
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作者 张昕仪 吴晔 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第7期325-328,共4页
In nonlinear optical systems,optical solitons have the transmission properties of reducing error rate,improving system security and stability,and have important research significance in future research on all optical ... In nonlinear optical systems,optical solitons have the transmission properties of reducing error rate,improving system security and stability,and have important research significance in future research on all optical communication.This paper uses the bilinear method to obtain the two-soliton solutions of the nonlinear Schrödinger equation.By analyzing the relevant physical parameters in the obtained solutions,the interaction between optical solitons is optimized.The influence of the initial conditions on the interactions of the optical solitons is analyzed in detail,the reason why the interaction of the optical solitons is sensitive to the initial condition is discussed,and the interactions of the optical solitons are effectively weakened.The relevant results are beneficial for reducing the error rate and promoting the communication quality of the system. 展开更多
关键词 optical solitons nonlinear Schrödinger equation soliton interactions
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All-optical switches based on three-soliton inelastic interaction and its application in optical communication systems
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作者 王树斌 张鑫 +1 位作者 马国利 朱岱寅 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第3期174-179,共6页
In high-speed optical communication systems,in order to improve the communication rate,the distance between pulses must be compressed,which will cause the problem of the interaction between optical pulses in optical c... In high-speed optical communication systems,in order to improve the communication rate,the distance between pulses must be compressed,which will cause the problem of the interaction between optical pulses in optical communication systems,which has been widely concerned by researches.In this paper,the bilinear method will be used to analyze the coupled high-order nonlinear Schro¨dinger equations and obtain their three-soliton solutions.Then,the influence of the relevant parameters in the three-soliton solution on the soliton inelastic interaction is studied.In addition,the constraint conditions of each parameter in the three-soliton solution are analyzed,the inelastic interaction properties of optical solitons under different parameter conditions are obtained,and the relevant laws of the inelastic interaction of solitons are studied.The results will have potential applications in the soliton control,all-optical switching and optical computing. 展开更多
关键词 optical solitons solitons interaction nonlinear Schro¨dinger equation soliton solution
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Three-dimensional choroidal vascularity index and choroidal thickness in fellow eyes of acute and chronic primary angle-closure using swept-source optical coherence tomography 被引量:1
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作者 Hai-Li Huang Guan-Hong Wang +1 位作者 Liang-Liang Niu Xing-Huai Sun 《International Journal of Ophthalmology(English edition)》 SCIE CAS 2024年第1期42-52,共11页
AIM:To compare the three-dimensional choroidal vascularity index(CVI)and choroidal thickness between fellow eyes of acute primary angle-closure(F-APAC)and chronic primary angle-closure glaucoma(F-CPACG)and the eyes of... AIM:To compare the three-dimensional choroidal vascularity index(CVI)and choroidal thickness between fellow eyes of acute primary angle-closure(F-APAC)and chronic primary angle-closure glaucoma(F-CPACG)and the eyes of normal controls.METHODS:This study included 37 patients with unilateral APAC,37 with asymmetric CPACG without prior treatment,and 36 healthy participants.Using swept-source optical coherence tomography(SS-OCT),the macular and peripapillary choroidal thickness and three-dimensional CVI were measured and compared globally and sectorally.Pearson’s correlation analysis and multivariate regression models were used to evaluate choroidal thickness or CVI with related factors.RESULTS:The mean subfoveal CVIs were 0.35±0.10,0.33±0.09,and 0.29±0.04,and the mean subfoveal choroidal thickness were 315.62±52.92,306.22±59.29,and 262.69±45.55μm in the F-APAC,F-CPACG,and normal groups,respectively.All macular sectors showed significantly higher CVIs and choroidal thickness in the F-APAC and F-CPACG eyes than in the normal eyes(P<0.05),while there were no significant differences between the F-APAC and F-CPACG eyes.In the peripapillary region,the mean overall CVIs were 0.21±0.08,0.20±0.08,and 0.19±0.05,and the mean overall choroidal thickness were 180.45±54.18,174.82±50.67,and 176.18±37.94μm in the F-APAC,F-CPACG,and normal groups,respectively.There were no significant differences between any of the two groups in all peripapillary sectors.Younger age,shorter axial length,and the F-APAC or F-CPACG diagnosis were significantly associated with higher subfoveal CVI and thicker subfoveal choroidal thickness(P<0.05).CONCLUSION:The fellow eyes of unilateral APAC or asymmetric CPACG have higher macular CVI and choroidal thickness than those of the normal controls.Neither CVI nor choroidal thickness can distinguish between eyes predisposed to APAC or CPACG.A thicker choroid with a higher vascular volume may play a role in the pathogenesis of primary angle-closure glaucoma. 展开更多
关键词 choroidal thickness choroidal vascularity index swept-source optical coherence tomography acute primary angle-closure chronic primary angle-closure glaucoma
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Attribute Reduction of Hybrid Decision Information Systems Based on Fuzzy Conditional Information Entropy 被引量:1
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作者 Xiaoqin Ma Jun Wang +1 位作者 Wenchang Yu Qinli Zhang 《Computers, Materials & Continua》 SCIE EI 2024年第5期2063-2083,共21页
The presence of numerous uncertainties in hybrid decision information systems(HDISs)renders attribute reduction a formidable task.Currently available attribute reduction algorithms,including those based on Pawlak attr... The presence of numerous uncertainties in hybrid decision information systems(HDISs)renders attribute reduction a formidable task.Currently available attribute reduction algorithms,including those based on Pawlak attribute importance,Skowron discernibility matrix,and information entropy,struggle to effectively manages multiple uncertainties simultaneously in HDISs like the precise measurement of disparities between nominal attribute values,and attributes with fuzzy boundaries and abnormal values.In order to address the aforementioned issues,this paper delves into the study of attribute reduction withinHDISs.First of all,a novel metric based on the decision attribute is introduced to solve the problem of accurately measuring the differences between nominal attribute values.The newly introduced distance metric has been christened the supervised distance that can effectively quantify the differences between the nominal attribute values.Then,based on the newly developed metric,a novel fuzzy relationship is defined from the perspective of“feedback on parity of attribute values to attribute sets”.This new fuzzy relationship serves as a valuable tool in addressing the challenges posed by abnormal attribute values.Furthermore,leveraging the newly introduced fuzzy relationship,the fuzzy conditional information entropy is defined as a solution to the challenges posed by fuzzy attributes.It effectively quantifies the uncertainty associated with fuzzy attribute values,thereby providing a robust framework for handling fuzzy information in hybrid information systems.Finally,an algorithm for attribute reduction utilizing the fuzzy conditional information entropy is presented.The experimental results on 12 datasets show that the average reduction rate of our algorithm reaches 84.04%,and the classification accuracy is improved by 3.91%compared to the original dataset,and by an average of 11.25%compared to the other 9 state-of-the-art reduction algorithms.The comprehensive analysis of these research results clearly indicates that our algorithm is highly effective in managing the intricate uncertainties inherent in hybrid data. 展开更多
关键词 Hybrid decision information systems fuzzy conditional information entropy attribute reduction fuzzy relationship rough set theory(RST)
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A Yb optical clock with a lattice power enhancement cavity
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作者 王春云 姚远 +3 位作者 师浩森 于洪浮 马龙生 蒋燕义 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第3期70-74,共5页
We construct a power enhancement cavity to form an optical lattice in an ytterbium optical clock.It is demonstrated that the intra-cavity lattice power can be increased by about 45 times,and the trap depth can be as l... We construct a power enhancement cavity to form an optical lattice in an ytterbium optical clock.It is demonstrated that the intra-cavity lattice power can be increased by about 45 times,and the trap depth can be as large as 1400Er when laser light with a power of only 0.6 W incident to the lattice cavity.Such high trap depths are the key to accurate evaluation of the lattice-induced light shift with an uncertainty down to~1×10-18.By probing the ytterbium atoms trapped in the power-enhanced optical lattice,we obtain a 4.3 Hz-linewidth Rabi spectrum,which is then used to feedback to the clock laser for the close loop operation of the optical lattice clock.We evaluate the density shift of the Yb optical lattice clock based on interleaving measurements,which is-0.46(62)mHz.This result is smaller compared to the density shift of our first Yb optical clock without lattice power enhancement cavity mainly due to a larger lattice diameter of 344μm. 展开更多
关键词 optical atomic clock optical lattice optical cavity Stark shift
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Automated evaluation of parapapillary choroidal microvasculature in crowded optic discs:a controlled,optical coherence tomography angiography study
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作者 Hatice Arda Hidayet Sener +5 位作者 Ozge Temizyurek Hatice Kubra Sonmez Duygu Gulmez Sevim Cem Evereklioglu Fatih Horozoglu Ayse Busra Gunay Sener 《International Journal of Ophthalmology(English edition)》 SCIE CAS 2024年第1期113-118,共6页
AIM:To compare superficial and deep vascular properties of optic discs between crowded discs and controls using optical coherence tomography angiography(OCT-A).METHODS:Thirty patients with crowded discs,and 47 control... AIM:To compare superficial and deep vascular properties of optic discs between crowded discs and controls using optical coherence tomography angiography(OCT-A).METHODS:Thirty patients with crowded discs,and 47 control subjects were enrolled in the study.One eye of each individual was included and OCT-A scans of optic discs were obtained in a 4.5×4.5 mm^(2) rectangular area.Radial peripapillary capillary(RPC)density,peripapillary retinal nerve fiber layer(pRNFL)thickness,cup volume,rim area,disc area,cup-to-disc(c/d)area ratio,and vertical c/d ratio were obtained automatically using device software.Automated parapapillary choroidal microvasculature(PPCMv)density was calculated using MATLAB software.When the vertical c/d ratio of the optic disc was absent or small cup,it was considered as a crowded disc.RESULTS:The mean signal strength index of OCT-A images was similar between the crowded discs and control eyes(P=0.740).There was no difference in pRNFL between the two groups(P=0.102).There were no differences in RPC density in whole image(P=0.826)and peripapillary region(P=0.923),but inside disc RPC density was higher in crowded optic discs(P=0.003).The PPCMv density in the inner-hemisuperior region was also lower in crowded discs(P=0.026).The pRNFL thickness was positively correlated with peripapillary RPC density(r=0.498,P<0.001).The inside disc RPC density was negatively correlated with c/d area ratio(r=-0.341,P=0.002).CONCLUSION:The higher inside disc RPC density and lower inner-hemisuperior PPCMv density are found in eyes with crowded optic discs. 展开更多
关键词 crowded optic disc ischemic optic neuropathy optical coherence tomography angiography parapapillary choroidal microvasculature
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Breaking the optical efficiency limit of virtual reality with a nonreciprocal polarization rotator
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作者 Yuqiang Ding Zhenyi Luo +1 位作者 Garimagai Borjigin Shin-Tson Wu 《Opto-Electronic Advances》 SCIE EI CAS CSCD 2024年第3期4-14,共11页
A catadioptric lens structure,also known as pancake lens,has been widely used in virtual reality(VR)displays to reduce the formfactor.However,the utilization of a half mirror(HM)to fold the optical path thrice leads t... A catadioptric lens structure,also known as pancake lens,has been widely used in virtual reality(VR)displays to reduce the formfactor.However,the utilization of a half mirror(HM)to fold the optical path thrice leads to a significant optical loss.The theoretical maximum optical efficiency is merely 25%.To transcend this optical efficiency constraint while retaining the foldable characteristic inherent to traditional pancake optics,in this paper,we propose a theoretically lossless folded optical system to replace the HM with a nonreciprocal polarization rotator.In our feasibility demonstration experiment,we used a commercial Faraday rotator(FR)and reflective polarizers to replace the lossy HM.The theoretically predicted 100%efficiency can be achieved approximately by using two high-extinction-ratio reflective polarizers.In addition,we evaluated the ghost images using a micro-OLED panel in our imaging system.Indeed,the ghost images can be suppressed to undetectable level if the optics are with antireflection coating.Our novel pancake optical system holds great potential for revolutionizing next-generation VR displays with lightweight,compact formfactor,and low power consumption. 展开更多
关键词 near-eye display virtual reality pancake optics folded optics nonreciprocal polarization rotator
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Optical facet coatings for high-performance LWIR quantum cascade lasers atλ∼8.5μm
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作者 MA Yuan LIN Yu-Zhe +5 位作者 WAN Chen-Yang WANG Zi-Xian ZHOU Xu-Yan ZHANG Jin-Chuan LIU Feng-Qi ZHENG Wan-Hua 《红外与毫米波学报》 SCIE EI CAS CSCD 北大核心 2024年第4期497-502,共6页
We report on the performance improvement of long-wave infrared quantum cascade lasers(LWIR QCLs)by studying and optimizing the anti-reflection(AR)optical facet coating.Compared to the Al2O3 AR coat⁃ing,the Y_(2)O_(3)A... We report on the performance improvement of long-wave infrared quantum cascade lasers(LWIR QCLs)by studying and optimizing the anti-reflection(AR)optical facet coating.Compared to the Al2O3 AR coat⁃ing,the Y_(2)O_(3)AR coating exhibits higher catastrophic optical mirror damage(COMD)level,and the optical facet coatings of both material systems have no beam steering effect.A 3-mm-long,9.5-μm-wide buried-heterostruc⁃ture(BH)LWIR QCL ofλ~8.5μm with Y_(2)O_(3)metallic high-reflection(HR)and AR of~0.2%reflectivity coating demonstrates a maximum pulsed peak power of 2.19 W at 298 K,which is 149%higher than that of the uncoated device.For continuous-wave(CW)operation,by optimizing the reflectivity of the Y_(2)O_(3)AR coating,the maximum output power reaches 0.73 W,which is 91%higher than that of the uncoated device. 展开更多
关键词 quantum cascade lasers long-wave infrared optical facet coatings catastrophic optical mirror damage
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