About the cover: Revealing complex optical phenomena through vectorial metrics
On the Cover: Highly integrated photonic crystal bandedge lasers monolithically grown on Si substrates
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On the Cover: Correlated triple hybrid amplitude and phase holographic encryption based on a metasurface
On the Cover: Silicon-integrated nonlinear III-V photonics

The image on the cover for Advanced Photonics Volume 4 Issue 2 illustrates a schematic of a Mueller matrix measurement system and a conceptional Mueller matrix of the sample (4x4 matrix), as well as the related vectorial properties of the light beams.The image is based on original research presented in the article by Chao He, Jintao Chang, Patrick S. Salter, Yuanxing Shen, Ben Dai, Pengcheng Li, Yihan Jin, Samlan Chandran Thodika, Mengmeng Li, Tariq Aziz, Jingyu Wang, Jacopo Antonello, Yang Dong, Ji Qi, Jianyu Lin, Daniel S. Elson, Min Zhang, Honghui He, Hui Ma, and Martin J. Booth, “ Revealing complex optical phenomena through vectorial metrics,” Adv. Photon. 4(2), 026001 (2022), doi 10.1117/1.AP.4.2.026001.

The image on the cover for Chinese Optics Letters Volume 20, Issue 4, indicates that an InAs/GaAs quantum dot photonic crystal bandedge laser, which is directly grown on an on-axis Si (001) substrate, which provides a feasible route towards a low-cost and large-scale integration method for light sources on the Si platform was achieved under the pumping condition of a continuous-wave 632.8 nm He–Ne gas laser at room temperature.The image is based on original research by Yaoran Huang et al. presented in their paper "Highly integrated photonic crystal bandedge lasers monolithically grown on Si substrates", Chinese Optics Letters 20 (4), 041401 (2022).

The image on the cover for Photonics Research Volume 10, Issue 3, demonstrates a correlated triple amplitude and phase holographic encryption based on an all-dielectric metasurface. An optimized holographic algorithm is developed to obtain quantitatively correlated triple holograms, which can encrypt information in multiple wavelength and polarization channels.The image is based on original research by Hongqiang Zhou et al. presented in their paper "Correlated triple hybrid amplitude and phase holographic encryption based on a metasurface", Photonics Research 10 (3), 03000678 (2022).

The image on the cover for Photonics Research Volume 10, Issue 2, demonstrates low-loss AlGaAs-on-SOI photonic circuits with integrated Si waveguides and showcase sub-milliwatt-threshold (∼0.25mW∼0.25mW) Kerr frequency comb generation in ultrahigh-??Q AlGaAs microrings (??Q over 106106) at the telecom bands.The image is based on original research by Weiqiang Xie et al. presented in their paper "Silicon-integrated nonlinear III-V photonics", Photonics Research 10 (2), 02000535 (2022).

Community-News
the 36th European Conference on Laser Interaction with Matter
ECLIM2022, the 36th European Conference on Laser Interaction with Matter will be held in Frascati, Italy on 19-23 September 2022.
High Power Laser Science and Engineering
  • May. 12, 2022
  • Vol. , Issue (2022)
Community-News
International Conference on X-Ray Laser 2022 (Both online and offline)
The ICXRL was established to promote advanced extreme UV and X-ray sources, and their application in physics, (bio-)chemistry, and materials science. Joining ICXRL means experiencing the latest trends, and shaping the future progress. Latest results on state-of-the-art X-ray Free-Electron Lasers (XFEL) as well as tabletop systems are presented. Lecturers are expected to submit a peer-reviewed paper for the SPIE monograph.
High Power Laser Science and Engineering
  • May. 12, 2022
  • Vol. , Issue (2022)
Spotlight on Optics
Phase-only Metasurfaces For Polarization-Multiplexed Holographic
With the development of virtual reality (VR) and augmented reality (AR) technology, the existing display technology is facing challenges and opportunities for providing vivid experience. Among many display technologies, holography shows extraordinary advantages in multi-dimensional optical recording and reconstruction, and is envisioned as the way to the ultimate visual feast.
Photonics Research
  • May. 11, 2022
  • Vol. 10, Issue 4 (2022)
Editors' Picks
Deep learning-based scattering removal of light field imaging
Light field imaging is a 3D imaging technology. In light field imaging, the projection of 3D object to light field information on 2D image plane (including spatial and directional information of incident light) will be conducted by micro-lens array. Then 3D reconstruction of object will be realized through the processing of light field information. Light field imaging has the feature of high-temporal-resolution with scanning-free 3D imaging process and has no requirement of special illumination. Therefore, light field imaging has shown significance in research fields and applications, such as biological imaging, industrial measurement and machine vision.
Chinese Optics Letters
  • May. 07, 2022
  • Vol. 20, Issue 4 (2022)
On the Cover
N-polar InGaN/GaN nanowires: overcoming the efficiency cliff of red-emitting micro-LEDs
High efficiency, high brightness, and robust micro or sub-microscale light emitting diodes (LEDs) are essential components of emerging virtual/augmented reality devices and systems as well as future ultrahigh resolution mobile displays. Realization of such ultra-small LEDs can also allow large scale integration of electronic and optoelectronic devices on the same chip.
Photonics Research
  • May. 03, 2022
  • Vol. 10, Issue 4 (2022)
Newest Articles
A novel needle probe for deeper photoacoustic viscoelasticity measurement

We present for the first time, to the best of our knowledge, a needle probe for photoacoustic viscoelasticity (PAVE) measurements at a depth of 1 cm below

We present for the first time, to the best of our knowledge, a needle probe for photoacoustic viscoelasticity (PAVE) measurements at a depth of 1 cm below the sample surface. The probe uses a gradient index rod lens, encased within a side-facing needle (0.7 mm outer diameter), to direct excitation light (532 nm) and detection light (1325 nm) focused on the sample, collecting and directing the returned detection light in a spectral domain low coherence interferometry system, which allows for obtaining optical phase differences due to photoacoustic oscillations. The feasibility of needle probe for PAVE depth characterization was investigated on gelatin phantoms and in vitro biological tissues. The experimental results in an in vivo animal model predict the great potential of this technique for in vivo tumor boundary detection.show less

  • May.27,2022
  • Chinese Optics Letters,Vol. 20, Issue 8
  • 081701 (2022)
Transfer of laser frequency from 729 nm to 1.5 µm with precision at the level of 10−20

By using a self-reference transfer oscillator method, two individual 1560 nm lasers with about 1.2 GHz frequency difference were phase locked to a 729 nm

By using a self-reference transfer oscillator method, two individual 1560 nm lasers with about 1.2 GHz frequency difference were phase locked to a 729 nm ultra-stable laser at two preset ratios. By measuring the beat frequency of the two 1560 nm lasers, fractional instabilities of 2×10-17 at 1 s and 2×10-20 at 10,000 s averaging time were obtained, and the relative offset compared with the theoretical value was 4.2×10-21±4.5×10-20. The frequency ratio of them was evaluated to a level of 1.3×10-20 in one day’s data acquisition. This work was a preparation for remote comparison of optical clocks through optical fiber links. The technique can also be used to synthesize ultra-stable lasers at other wavelengths.show less

  • May.27,2022
  • Chinese Optics Letters,Vol. 20, Issue 8
  • 081403 (2022)
Dynamics of multi-state in a simplified mode-locked Yb-doped fiber laser

The dispersive Fourier transform technique provides feasibility of exploring non-repetitive events and the buildup process in ultrafast lasers. In this pa

The dispersive Fourier transform technique provides feasibility of exploring non-repetitive events and the buildup process in ultrafast lasers. In this paper, we report a new buildup process of dissipative solitons in a simplified mode-locked Yb-doped fiber laser, which includes more complex physics stages such as the Q-switching stage, raised and damped relaxation oscillation stages, noise-like stage, successive soliton explosions stage, and soliton breathing stage. Complete evolution dynamics of noise-like pulse and double pulse are also investigated with dispersive Fourier transform. For the noise-like pulse dynamics process, it will only experience the Q-switching and relaxation oscillation stages. In the case of dissipative soliton and noise-like pulse, the double pulse buildup behavior is manifested as the replication of individual pulses. A weak energy migration occurs between two pulses before reaching steady state. Meanwhile, real-time mutual conversion of the dissipative soliton and noise-like pulse has been experimentally observed, which appears to be instantaneous without extra physical processes. To the best of our knowledge, this is the first report on these physical phenomena observed together in a mode-locked fiber laser. The results further enrich the dynamics of mode-locked fiber lasers and provide potential conditions for obtaining intelligent mode-locked lasers with controllable output.show less

  • May.27,2022
  • Chinese Optics Letters,Vol. 20, Issue 8
  • 081402 (2022)
High-power narrow-linewidth diode laser pump source based on high-efficiency external cavity feedback technology

In this research, the highly efficient external cavity feedback technology based on volume Bragg grating (VBG) is studied. By using the structure of a fas

In this research, the highly efficient external cavity feedback technology based on volume Bragg grating (VBG) is studied. By using the structure of a fast axis collimating lens, the beam transformation system, a slow axis collimating lens, and VBG, the divergence angle of the fast and slow axes of the diode laser incident on the VBG is reduced effectively, and the feedback efficiency of the external cavity is improved. Combined with beam combining technology, fiber coupling technology, and precision temperature control technology, a high-power and narrow-linewidth diode laser pump source of kilowatt class is realized for alkali metal vapor laser pumping. The core diameter of the optical fiber is 1000 µm, the numerical aperture is 0.22, the output power from the fiber is 1013 W, the fiber coupling efficiency exceeds 89%, and the external cavity efficiency exceeds 91%. The central wavelength is 852.052 nm (in air), which is tunable from 851.956 nm to 852.152 nm, and the spectral linewidth is 0.167 nm. Research results can be used for cesium alkali metal vapor laser pumping.show less

  • May.27,2022
  • Chinese Optics Letters,Vol. 20, Issue 8
  • 081401 (2022)
Optics Physics Geography

Constructions of synthetic lattices in modulated ring resonators attract growing attentions for exploring interesting physics beyond the geometric dimensionality, where complicated conn

Constructions of synthetic lattices in modulated ring resonators attract growing attentions for exploring interesting physics beyond the geometric dimensionality, where complicated connectivities between resonant frequency modes are explored in many theoretical proposals. Here, we implement the experimental demonstration of generating the stub lattice along the frequency axis of light, realized in two coupled ring resonators of different lengths while the larger ring undergoing dynamic modulation. Such synthetic photonic structure naturally exhibits the physics of flat band. We show that the time-resolved band structure read out from the drop-port output of the excited ring is the intensity projection of the band structure onto specific resonant mode in the synthetic momentum space, where gapped flat band, mode localization effect, and flat to non-flat band transition are observed in experiments and verified by simulations. Our work gives a direct evidence for the constructing synthetic stub lattice using two different rings, which hence makes a solid step towards experimentally constructing more complicated lattices in multiple rings associated with synthetic frequency dimension.show less

  • May.27,2022
  • Advanced Photonics

Entanglement serves as a fundamental resource for quantum information protocols, and hyperentanglement has received an explosively increasing amount of attention for its high-capacity c

Entanglement serves as a fundamental resource for quantum information protocols, and hyperentanglement has received an explosively increasing amount of attention for its high-capacity characteristic. Increasing the scale of hyperentanglement, i.e., the number of modes in a hyperentangled system, is crucial for enhancing its capability in quantum information processing. Here we demonstrate the generation of large-scale continuous-variable (CV) hyperentanglement in three degrees of freedom (DOFs), including azimuthal and radial indexes of Laguerre-Gaussian (LG) modes and frequency. In our experiment, 216 pairs of hyperentangled modes are deterministically generated from the four-wave mixing process in an atomic vapor. Besides, we show that the entanglement between coherent LG superposition modes denoted by both azimuthal and radial quantum numbers can also be generated from this system. Such large-scale CV hyperentanglement in three DOFs presents an efficient scheme to significantly increase the information capacity of the CV system. Our results provide a new platform for studying CV quantum information and open the avenue for constructing high-capacity parallel and multiple-DOF CV quantum information protocols.show less

  • May.27,2022

The temporal evolutions of electron density and plasma diameter of 1 kHz filament in air are investigated by utilizing a pump-probe longitudinal diffraction method. A model based on sca

The temporal evolutions of electron density and plasma diameter of 1 kHz filament in air are investigated by utilizing a pump-probe longitudinal diffraction method. A model based on scalar diffraction theory is proposed to extract the phase shift from the diffraction patterns. The hydrodynamic effect on plasma evolution at 1 kHz filament is included and analyzed. The measured initial peak electron density ~10^18 cm^-3 in our experimental conditions decays rapidly by nearly two orders of magnitude within 200 ps. Moreover, the plasma channel size rises from 90μm to 120μm as the delay time increases. The experimental observation is in agreement with numerical simulation results by solving the rate equations.show less

  • May.27,2022
  • Chinese Optics Letters,Vol. 20, Issue 9
  • (2022)

Snapshot spectral ghost imaging, which can acquire the dynamic spectral imaging information in the field of view, has attracted more attention in recent years. Studies have shown that o

Snapshot spectral ghost imaging, which can acquire the dynamic spectral imaging information in the field of view, has attracted more attention in recent years. Studies have shown that optimizing the fluctuation of light fields is essential to improve the sampling efficiency and the reconstruction quality of ghost imaging. However, the optimization of broadband light fields in snapshot spectral ghost imaging is challenging due to the dispersion of the modulation device. In the paper, by judiciously introducing a hybrid refraction/diffraction structure into the light field modulation, a snapshot spectral ghost imaging with broadband super-Rayleigh speckles was demonstrated. Simulation and experimental results verify that the contrast of speckles in a broad range of wavelengths has been significantly improved, and the imaging system has superior noise immunity.show less

  • May.27,2022
  • Chinese Optics Letters,Vol. 20, Issue 9
  • (2022)
The image on the cover for Advanced Photonics Volume 4 Issue 2 illustrates a schematic of a Mueller matrix measurement system and a conceptional Mueller matrix of the sample (4x4 matrix), as well as the related vectorial properties of the light beams.The image is based on original research presented in the article by Chao He, Jintao Chang, Patrick S. Salter, Yuanxing Shen, Ben Dai, Pengcheng Li, Yihan Jin, Samlan Chandran Thodika, Mengmeng Li, Tariq Aziz, Jingyu Wang, Jacopo Antonello, Yang Dong, Ji Qi, Jianyu Lin, Daniel S. Elson, Min Zhang, Honghui He, Hui Ma, and Martin J. Booth, “ Revealing complex optical phenomena through vectorial metrics,” Adv. Photon. 4(2), 026001 (2022), doi 10.1117/1.AP.4.2.026001.
  • Journal
  • 23th May,2022
The image on the cover for Chinese Optics Letters Volume 20, Issue 4, indicates that an InAs/GaAs quantum dot photonic crystal bandedge laser, which is directly grown on an on-axis Si (001) substrate, which provides a feasible route towards a low-cost and large-scale integration method for light sources on the Si platform was achieved under the pumping condition of a continuous-wave 632.8 nm He–Ne gas laser at room temperature.The image is based on original research by Yaoran Huang et al. presented in their paper "Highly integrated photonic crystal bandedge lasers monolithically grown on Si substrates", Chinese Optics Letters 20 (4), 041401 (2022).
  • Journal
  • 18th Apr,2022