2022

• Record 49 of
  
  Title:Laser Active Fusion Trajectory Measurement Technology in Rocket Take-off Phase
  
  Author(s):Shi, Heng(1,2,3,4); Gao, Xin(1); Li, Xiyu(1); Lei, Chengqiang(1); Hu, Lei(1); Zong, Yonghong(1); Zheng, Donghao(1); Sun, Rui(1)
  Source: Guangzi Xuebao/Acta Photonica Sinica  Volume: 51  Issue: 12  DOI: 10.3788/gzxb20225112.1212001  Published: 2022  
  Abstract:The high-precision trajectory data of the rocket vertical take-off phase can be used to evaluate the technical performance and accuracy of the rocket，provide data reference for the improved design and finalization of the rocket，and also provide important trajectory reference data for the rocket take-off safety control system. The trajectory of the rocket in the vertical take-off phase changes greatly in the vertical rising direction，while the theoretical trajectory in both directions of the horizontal plane does not change. However，in the actual launch process，due to various interferences and certain delays and deviations in the real-time control of the rocket，the actual trajectory of the rocket in the horizontal plane will inevitably have a certain offset. The traditional trajectory measurement methods in the vertical take-off phase of rocket mainly include telemetry，optical and radio radar measurement. Due to the vibration caused by rocket launch，the trajectory measurement accuracy of telemetry system is not high，and it is difficult to obtain effective original analysis data after rocket failure. The optical measurement system uses images taken by multiple stations to obtain the rocket trajectory data after the rendezvous，but it is easily affected by the weather and has poor real-time performance. Due to the interference of ground clutter，it is difficult for radio radar to obtain effective trajectory data at this stage. It can be seen that there is no real-time trajectory measurement data in the vertical take-off phase of the rocket at present，and it is urgent to fill the data gap in this phase through new measurement methods.A single lidar can be used to measure the rocket trajectory in the take-off phase，but the trajectory data of the rocket in both directions of the horizontal plane in the vertical take-off phase changes very little，and only relying on a single lidar to measure the trajectory in the two directions will cause large errors. Compared with a single lidar measurement system，the field of view of the two multi-line lidars in the vertical direction can reach 25°，and a total of 128 laser scanning lines scan the rocket target area at the same time. In addition，the two lidars conduct fusion measurement at an intersection angle of 70°，which can cover the target area of the rocket with a larger angle range. Therefore，more target measurement points can be scanned，which can not only improve the fitting accuracy of the center of the ellipse ，but also effectively ensure the reliability of the data measurement. In view of the difficult technical problem of obtaining real-time high-precision trajectory data in the rocket vertical takeoff phase，a new rocket take-off phase trajectory fusion measurement system based on lidar is proposed in this paper，which has the advantages of convenient station layout，easy installation and low power consumption. At the same time，it is less affected by weather，ground clutter signals and rocket vibration，and can effectively obtain the rocket real-time trajectory data. Two lidars are installed on a two-dimensional precision turntable to form a fusion measurement system. Before the launch of the rocket，the two lidars jointly scan the middle and upper target areas of the rocket. Based on the proposed algorithm of laser point cloud data correction，the initial value solution of rocket target area trajectory and data fusion processing of the two trajectory data，the static and dynamic trajectory measurement accuracy of the lidar are calculated and analyzed to be 0.023 5 m and 0.036 6 m respectively. In the process of rocket vertical take-off，the two-dimensional precision turntable receives the trajectory data of the rocket target area in real time，guides the lidar to track and scan the whole process of the rocket vertical take-off phase with high precision according to the rocket position information，and completes the real-time and high-precision trajectory measurement of the rocket vertical take-off phase，which effectively fills the gap of the trajectory measurement data of the rocket at this stage and ensures the safety of rocket launch. Up to now，the rocket real-time trajectory measurement system based on lidar has successfully completed many test tasks in a satellite launch center. Under the conditions of vibration，tail flame and other environmental interference in the rocket take-off phase，the real-time dynamic trajectory measurement accuracy can be better than 0.05 m. It is verified that the measurement system and method proposed in this paper can effectively improve the measurement accuracy and reliability of rocket trajectory，which has important engineering application value. © 2022 Chinese Optical Society. All rights reserved.
  Accession Number: 20230813622786
• Record 50 of
  
  Title:Theoretical Model of Thermal Stress in the Film-Substrate System of Optical Thin Film
  
  Author(s):Shi, Yunyun(1,2); Xu, Junqi(1); Li, Yang(1); Liu, Zheng(2); Zhang, Kaifeng(3); Su, Junhong(1)
  Source: Journal of Electronic Materials  Volume: 51  Issue: 10  DOI: 10.1007/s11664-022-09819-w  Published: October 2022  
  Abstract:A model of thermal stress in double-layer optical dielectric films on circular substrates was established based on the theory of double-layer composite beams. Here, considering the boundary conditions including force balance and bending moment balance, the distribution of stress and strain in the double-layer film-substrate system was analyzed following equivalence manipulation to determine a detailed formula for calculating the thermal stress in the equivalent film and substrate. The derived formula was not only effective in analyzing the stress and strain of the double-layer film-substrate system but was also applicable for predicting the distribution of thermal stress in the periodic elastic multilayer film-substrate system. According to the actual radius of curvature of the substrate measured via a profilometer before and after the deposition of the HfO2/SiO2 double-layer films, the obtained residual stress of the film was − 79.33 MPa, whereas the thermal stress of the film was calculated to be −52.59 MPa using the theoretical formula. The calculations of the theoretical model were similar to the experimental results when the smaller intrinsic stresses were neglected and the double-layer film was only of nanometer thickness, thus verifying the effectiveness of the double-layer film-substrate model. © 2022, The Minerals, Metals & Materials Society.
  Accession Number: 20223412602126
• Record 51 of
  
  Title:Large-field structured illumination microscopy based on 2D grating and a spatial light modulator
  
  Author(s):Wen, Kai(1,2); Fang, Xiang(1); Ma, Ying(1); Liu, Min(1); An, Sha(1); Zheng, JuanJuan(1,3); Kozacki, Tomasz(2); Gao, Peng(1)
  Source: Optics Letters  Volume: 47  Issue: 11  DOI: 10.1364/OL.460292  Published: June 1, 2022  
  Abstract:Structured illumination microscopy (SIM) has been widely used in biological research due to its merits of fast imaging speed, minimal invasiveness, super-resolution, and optical sectioning imaging capability. However, the conventional SIM that uses a spatial light modulator (SLM) for fringe projection often has a limited imaging field of view. Herein, we report a large-field SIM technique that combines a 2D grating for fringe pattern projection and an SLM for selecting fringe orientation and performing phase shifting digitally. The proposed SIM technique breaks the bottleneck of fringe number limited by the digital projection devices, while maintaining the advantage of high-speed (digital) phase shifting of conventional SIM. The method avoids the pixilation and dispersion effects of the SLMs. Finally, a 1.8-fold resolution enhancement in a large field of 690 × 517 µm2 under a 20×/NA0.75 objective is experimentally demonstrated. The proposed technique can be widely applied to biology, chemistry, and industry. © 2022 Optica Publishing Group
  Accession Number: 20222212182743
• Record 52 of
  
  Title:Secondary electron emission of Al2O3 and MgO nanofilms fabricated by atomic layer deposition
  
  Author(s):Zhu, Xiangping(1,2); Wang, Dan(3); Wang, Hui(4,5); Zhou, Rundong(1,2); Li, Xiangxin(1); Hong, Yunfan(1); Jin, Chuan(1); Wei, Yonglin(1); Luo, Chaopeng(4,5); Zhao, Wei(1,2)
  Source: Kexue Tongbao/Chinese Science Bulletin  Volume: 67  Issue: 23  DOI: 10.1360/TB-2022-0175  Published: 2022  
  Abstract:Electron multiplier devices are widely applied in many electronic instruments like mass spectrometers and atomic clocks. It is considerably crucial for a multiplier to possess a high electron gain, and this index can be directly determined by secondary electron yield (SEY) of the dynodes. Al2O3 and MgO possess a relatively high SEY level among majority of dynode materials, and their film products are excellent dynode candidates. Whereas, for some multipliers like microchannel plate (MCP), only an ultrathin film of several nanometers is allowed to be coated onto the inner wall of the micro channels to avoid the variation of the channel diameter. Therefore, SEY characteristics of the ultrathin films are necessary to be figured out. Here, by using the technology of atomic layer deposition, 7 groups of ultrathin Al2O3 and MgO nanofilms with increase thickness (1, 3, 5, 7, 10, 30, and 50 nm) are fabricated on silicon (Si) substrates. As well as, 5 groups of Al2O3 nanofilms (1, 2, 3, 4, and 20 nm) are deposited on MgO film (20 nm) substrate. Surface composition, morphology, film thickness, and SEY have been characterized in detail. Via the experiments, it is found that SEY of the Al2O3/Si and MgO/Si samples largely depends on the film thickness, namely, SEY increases obviously as the film thickness rises, meanwhile, the increment of SEY decreases gradually. The SEY tendency indicates that the effect of top film on SEY becomes enhanced, and the influence of bottom substrate on SEY becomes weakened. When the film thickness increases beyond 30 nm, SEY increment approaches to 0, and SEY tends to be saturated. This phenomenon demonstrates that the penetration depth of incident electrons is less than the film thickness under the circumstances. To interpret the experimental results, the SEE semi-physical theory developed for double layer structures is utilized. The calculation results indicate that the film thickness has a remarkable impact on SEY, especially when the incident energy becomes lower and the film becomes thicker, the results also reveal that the dielectric surface film possesses a great ability to modulate the surface SEY. However, SEY becomes less dependent on film thickness as the incident energy increases, and it results from the increase of penetration depth for the incident electrons. This work reveals the mechanism of the SEE characteristics for ultrathin Al2O3 and MgO nanofilms, which is of great significance for the subsequent research on the use of nanoscale high SEY dielectric films as the SEE functional layer in electron multipliers. © 2022 Chinese Academy of Sciences. All rights reserved.
  Accession Number: 20223712734072
• Record 53 of
  
  Title:Broadband Fiber Chirped-pulse Amplification System Based on Parabolic Evolution
  
  Author(s):Du, Li(1); Jin, Cuihong(1); Yang, Zhi(2); Cui, Yudong(1,3)
  Source: Guangzi Xuebao/Acta Photonica Sinica  Volume: 51  Issue: 11  DOI: 10.3788/gzxb20225111.1114002  Published: November 2022  
  Abstract:Fiber lasers have attracted substantial research interest due to their high stability， excellent beam quality and system compactness. Furthermore， lasers generating high-energy ultrafast pulses and operating at the 1 550 nm region are widely developed due to the low optical attenuation at the first communication window and more cost-effective than other laser sources in a variety of applications such as ultrafast spectroscopy， precision material processing and terahertz-wave generation. To achieve high-energy pulses， an Erbium-doped fiber amplifier was employed to amplify seed pulses. However， pulses will accumulate large nonlinear effects such as Self-Phase Modulation （SPM） and Stimulated Raman Scattering （SRS） during direct amplification， thus degrading the pulse quality. One common solution is to widen the pulse width by introducing a chirp before amplification. The peak power intensity is significantly attenuated， avoiding excessive nonlinearity. The amplified pulse is then de-chirped by a compressor. This method is called chirped pulse amplification （CPA）. Several high-power CPA systems operating at 1.56 μm have been demonstrated in recent years. However， all of these sources produced a pulse with spectral width between 5 nm and 15 nm. Broadband fiber laser plays an important role in optical frequency combs， optical coherent tomography， optical coherence radar and fiber optical sensing systems. There is a lack of high-energy devices capable of generating pulses with spectral width above 30 nm. Several approaches have been utilized to generate broadband pulses. A noise-like mode-locked fiber laser was demonstrated based on the precise adjustment of intracavity dispersion. However， this laser regime was seldom applied in ultrashort pulses due to its incompressibility. A Mamyshev oscillator is able to generate broadband pulses as shorter than 100 fs at the expense of complicated intracavity structure and accurate pulse evolution. The extra-cavity generation method relies on Highly Nonlinear Fibers （HNLFs）， such as photonic crystal fibers， whose complexity of design is increased by demanding careful selection of parameters for the seed pulse. In addition， the nonlinear effect induced by SPM generates a nonlinear chirp on both sides of pulses which degrades the beam quality in CPA systems. Note that self-similar pulses are nonlinear optical structures whose amplitudes and widths could be altered by dispersion， nonlinearity， gain and other system parameters， while maintaining the overall shapes. Since the self-similar pulse has a strict linear frequency chirp induced by the balance between SPM and normal group velocity dispersion in the erbium-doped fiber， it could be effectively compressed by grating pairs to obtain a high-power ultrashort pulse. Therefore， the combination of self-similar amplification and CPA is a promising solution to generating broadband watt-level pulse. High-energy ultrafast pulses based on parabolic evolution in ytterbium-doped lasers have been reported. Nevertheless， the Erbium-Doped Fiber Amplifier （EDFA） based on self-similar amplification operates at an anomalous dispersion region， which is less applicable to generating pulses with the average power above watt-level high-energy pulses comparing to Ytterbium-Doped Fiber Amplifier （YDFA）. At the same time， high-energy CPA systems operating at 1 550 nm significantly lag behind Yb-doped lasers due to high quantum defect， thermal effects and nonlinearity. At present， there is no report on a broadband high-energy CPA system based on parabolic evolution operating at 1 550 nm. Here， we demonstrated an all-fiber Er-doped chirped-pulse amplification laser， which generates Watt-level broadband pulse with the application of self-similar amplification. Numerical simulations of the model laser were performed by following the propagation of the pulses and considering every action of cavity components on the pulses. We use the results of one round-trip circulation as the input of the next round of calculation until the optical field becomes self-consistent. For this context， pulse propagation equation is given by the nonlinear Schrodinger equation. The parameters of each element of the laser are optimized according to theoretical simulations. In our experiment， the seed source is a dispersion-managed passively mode-locked fiber laser with a Gaussian-spectral profile， which evolves into a parabolic shape after self-similar amplification， achieving a broadband pulse bandwidth with the full-width at a half-maximum of 44.8 nm under 400 mW pump power. The spectral width and energy of the pulse increase rapidly during amplification. The pulses are stretched in Dispersion Compensating Fiber （DCF） to reduce peak power， avoiding excessive nonlinearity. Then a Double-Clad Er/Yb co-Doped Fiber （DC-EYDF） is used as the main amplifier. The spectral width of the pulse is narrowed down to 30 nm with the effect of gain filtering during amplification. The pulse is amplified to 1.3 W with the pump power of 9 W. The amplifier delivers 32 nJ pulses at a repetition rate of 40.1 MHz， which can be compressed down to 587 fs through a pair of transmission gratings. We believe that the narrower pulses could be achieved by switching to fiber Bragg gratings to adjust the dispersion between the stretchers and compressors precisely. The robust， broadband， and watt-level 1 550 nm fiber laser source can be used for nonlinear frequency conversion， solar cell micromachining and ophthalmology due to its compact size. © 2022 Chinese Optical Society. All rights reserved.
  Accession Number: 20224513074550
• Record 54 of
  
  Title:Enhancement of Fiber-to-Waveguide Coupling Efficiency of Silicon Nitride Integrated Optical Circuits
  
  Author(s):Zhu, Xiaotian(1); Li, Guangkuo(1); Li, Yuhua(4); Wang, Xiang(2); Davidson, Roy(2); Little, Brent E.(2,3); Chu, Sai T.(1)
  Source: 2022 Conference on Lasers and Electro-Optics Pacific Rim, CLEO-PR 2022 - Proceedings  Volume:   Issue:   DOI: 10.1109/CLEO-PR62338.2022.10432431  Published: 2022  
  Abstract:A hybrid approach for the enhancement of the fiber-to-silicon nitride waveguide coupling efficiency is proposed. It shows the coupling efficiency of lower than 0.7 dB/facet across the C band can be achieved. © 2022 IEEE.
  Accession Number: 20241115716953
• Record 55 of
  
  Title:The complex Maxwell stress tensor theorem: The imaginary stress tensor and the reactive strength of orbital momentum. A novel scenery underlying electromagnetic optical forces
  
  Author(s):Nieto-Vesperinas, Manuel(1); Xu, Xiaohao(2,3)
  Source: Light: Science and Applications  Volume: 11  Issue: 1  DOI: 10.1038/s41377-022-00979-2  Published: December 2022  
  Abstract:We uncover the existence of a universal phenomenon concerning the electromagnetic optical force exerted by light or other electromagnetic waves on a distribution of charges and currents in general, and of particles in particular. This conveys the appearence of underlying reactive quantities that hinder radiation pressure and currently observed time-averaged forces. This constitutes a novel paradigm of the mechanical efficiency of light on matter, and completes the landscape of the optical, and generally electromagnetic, force in photonics and classical electrodynamics; widening our understanding in the design of both illumination and particles in optical manipulation without the need of increasing the illuminating power, and thus lowering dissipation and heating. We show that this may be accomplished through the minimization of what we establish as the reactive strength of orbital (or canonical) momentum, which plays against the optical force a role analogous to that of the reactive power versus the radiation efficiency of an antenna. This long time overlooked quantity, important for current progress of optical manipulation, and that stems from the complex Maxwell theorem of conservation of complex momentum that we put forward, as well as its alternating flow associated to the imaginary part of the complex Maxwell stress tensor, conform the imaginary Lorentz force that we introduce in this work, and that like the reactive strength of orbital momentum, is antagonistic to the well-known time-averaged force; thus making this reactive Lorentz force indirectly observable near wavelengths at which the time-averaged force is lowered. The Minkowski and Abraham momenta are also addressed. © 2022, The Author(s).
  Accession Number: 20224212968254
• Record 56 of
  
  Title:An Optimization Algorithm for Optical Gain in the Multi-EDFAs-based Fiber-optic Time Synchronization
  
  Author(s):Liu, Bo(1,2); Kong, Weicheng(3,4); Guo, Xinxing(3,4); Li, Bo(3,4); Zhang, Shougang(3,4); Dong, Ruifang(3,4); Liu, Tao(3,4)
  Source: 2022 Joint Conference of the European Frequency and Time Forum and IEEE International Frequency Control Symposium, EFTF/IFCS 2022 - Proceedings  Volume:   Issue:   DOI: 10.1109/EFTF/IFCS54560.2022.9850958  Published: 2022  
  Abstract:This article reports an optimization model of optical fiber time synchronization EDFA gain coefficient based on genetic algorithm (G A). According to a series of parameters such as the distance and attenuation of each section of optical fiber, the EDFA gain coefficient of each node is obtained for the purpose of maximizing the signal-to-noise ratio, SNR. This algorithm is further exploited for regulating the gains of bidirectional amplifiers, allowing optimization of the performance of the link. The developed algorithm was tested experimentally done with 210-and 300-km-long links in the laboratory, incorporating three and four amplifiers. The results suggest that, comparing with the fixed gain coefficient setting, the proposed solutions allow optimizing the SNR by 3-5 dB and reduce the phase jitter by about 20%. © 2022 IEEE.
  Accession Number: 20223712712947
• Record 57 of
  
  Title:The route to a 200 MHz, all-PM femtosecond Yb-doped fiber laser with a high output coupling ratio
  
  Author(s):Zhang, Zhao(1,2); Zhang, Tong(1,2); Lv, Zhiguo(3); Zhang, Ting(1,2); Cheng, Haihao(1,2); Hu, Xiaohong(1); Pan, Ran(1); Feng, Ye(1); Wang, Yishan(1)
  Source: Applied Optics  Volume: 61  Issue: 28  DOI: 10.1364/AO.472038  Published: October 1, 2022  
  Abstract:Based on the time-independent rate equations and nonlinear Schrödinger equation, we simulate a 200 MHz all-polarization-maintaining (PM) mode-locked Yb-doped fiber laser. The cavity round trip evolution toward stable mode locking is present. Additionally, the gain coefficients along the gain fiber as well as the pulses, chirp, and spectra at different locations in the cavity are examined. The effects of chirped fiber Bragg grating parameters on the pulse shape and spectrum profile are also investigated. According to the calculations, we experimentally realize a 200 MHz femtosecond fiber laser with 115 mW output power. The timing jitter and integrated relative intensity noise are measured as 158 fs (1 kHz to 10 MHz) and 0.0513% (1 Hz to 300 kHz), respectively. Eventually, an amplified average power of 610 mW and 79 fs compressed pulses with a peak power of approximately 28 kW are obtained. The exhibited all-PM femtosecond fiber laser system can be adopted as the foundation for an optical frequency comb. © 2022 Optica Publishing Group.
  Accession Number: 20224212986017
• Record 58 of
  
  Title:Eagle-Eye-Inspired Attention for Object Detection in Remote Sensing
  
  Author(s):Liu, Kang(1,2); Huang, Ju(1,2,3); Li, Xuelong(1,2)
  Source: Remote Sensing  Volume: 14  Issue: 7  DOI: 10.3390/rs14071743  Published: April-1 2022  
  Abstract:Object detection possesses extremely significant applications in the field of optical remote sensing images. A great many works have achieved remarkable results in this task. However, some common problems, such as scale, illumination, and image quality, are still unresolved. Inspired by the mechanism of cascade attention eagle-eye fovea, we propose a new attention mechanism network named the eagle-eye fovea network (EFNet) which contains two foveae for remote sensing object detection. The EFNet consists of two eagle-eye fovea modules: front central fovea (FCF) and rear central fovea (RCF). The FCF is mainly used to learn the candidate object knowledge based on the channel attention and the spatial attention, while the RCF mainly aims to predict the refined objects with two subnetworks without anchors. Three remote sensing object-detection datasets, namely DIOR, HRRSD, and AIBD, are utilized in the comparative experiments. The best results of the proposed EFNet are obtained on the HRRSD with a 0.622 AP score and a 0.907 AP50 score. The experimental results demonstrate the effectiveness of the proposed EFNet for both multi-category datasets and single category datasets. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.
  Accession Number: 20221712029080
• Record 59 of
  
  Title:Staging of Skin Cancer Based on Hyperspectral Microscopic Imaging and Machine Learning
  
  Author(s):Liu, Lixin(1,2); Qi, Meijie(1,2); Li, Yanru(1); Liu, Yujie(1); Liu, Xing(3); Zhang, Zhoufeng(2); Qu, Junle(4)
  Source: Biosensors  Volume: 12  Issue: 10  DOI: 10.3390/bios12100790  Published: October 2022  
  Abstract:Skin cancer, a common type of cancer, is generally divided into basal cell carcinoma (BCC), squamous cell carcinoma (SCC) and malignant melanoma (MM). The incidence of skin cancer has continued to increase worldwide in recent years. Early detection can greatly reduce its morbidity and mortality. Hyperspectral microscopic imaging (HMI) technology can be used as a powerful tool for skin cancer diagnosis by reflecting the changes in the physical structure and microenvironment of the sample through the differences in the HMI data cube. Based on spectral data, this work studied the staging identification of SCC and the influence of the selected region of interest (ROI) on the staging results. In the SCC staging identification process, the optimal result corresponded to the standard normal variate transformation (SNV) for spectra preprocessing, the partial least squares (PLS) for dimensionality reduction, the hold-out method for dataset partition and the random forest (RF) model for staging identification, with the highest staging accuracy of 0.952 ± 0.014, and a kappa value of 0.928 ± 0.022. By comparing the staging results based on spectral characteristics from the nuclear compartments and peripheral regions, the spectral data of the nuclear compartments were found to contribute more to the accurate staging of SCC. © 2022 by the authors.
  Accession Number: 20231213758750
• Record 60 of
  
  Title:Large aperture phase-coded diffractive lens for achromatic and 16° field-of-view imaging with high efficiency
  
  Author(s):Ma, Gu(1,2); Zheng, Peng-Lei(1,2); Hu, Zheng-Wen(1,2); Ma, Suo-Dong(1,2,3); Xu, Feng(1,2); Pu, Dong-Lin(1,2); Wang, Qin-Hua(1,2)
  Source: Chinese Physics B  Volume: 31  Issue: 7  DOI: 10.1088/1674-1056/ac560c  Published: July 1, 2022  
  Abstract:Diffractive lenses (DLs) can realize high-resolution imaging with light weight and compact size. Conventional DLs suffer large chromatic and off-axis aberrations, which significantly limits their practical applications. Although many achromatic methods have been proposed, most of them are used for designing small aperture DLs, which have low diffraction efficiencies. In the designing of diffractive achromatic lenses, increasing the aperture and improving the diffraction efficiency have become two of the most important design issues. Here, a novel phase-coded diffractive lens (PCDL) for achromatic imaging with a large aperture and high efficiency is proposed and demonstrated experimentally, and it also possesses wide field-of-view (FOV) imaging at the same time. The phase distribution of the conventional phase-type diffractive lens (DL) is coded with a cubic function to expand both the working bandwidth and the FOV of conventional DL. The proposed phase-type DL is fabricated by using the laser direct writing of grey-scale patterns for a PCDL of a diameter of 10 mm, a focal length of 100 mm, and a cubic phase coding parameter of 30π. Experimental results show that the working bandwidth and the FOV of the PCDL respectively reach 50 nm and 16° with over 8% focusing efficiency, which are in significant contrast to the counterparts of conventional DL and in good agreement with the theoretical predictions. This work provides a novel way for implementing the achromatic, wide FOV, and high-efficiency imaging with large aperture DL. © 2022 Chinese Physical Society and IOP Publishing Ltd.
  Accession Number: 20223012413010