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).
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
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
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
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
A home-made low loss Bi/P co-doped silica fiber was fabricated using the modified chemical vapor deposition technique (MCVD) combined with the solution doping method, where the backgrou
A home-made low loss Bi/P co-doped silica fiber was fabricated using the modified chemical vapor deposition technique (MCVD) combined with the solution doping method, where the background loss at 1550 nm was as low as 17 dB/km. We demonstrated for the first time an all-fiber amplifier using the home-made Bi/P co-doped fiber achieving the broadband amplification in E-band. The amplifying performance was evaluated and optimized with different pumping pattern and fiber length. A maximum net gain at 1355 nm close to 20 dB and a minimum NF of 4.6 dB were obtained for the first time using two 1240 nm LDs under bidirectional pumping with the input pump and signal power of 870 mW and -30 dBm，respectively. show less
Metasurfaces are ultrathin metamaterials constructed by planar meta-atoms with tailored electromagnetic responses. They have attracted tremendous attention owing to their ability to fre
Metasurfaces are ultrathin metamaterials constructed by planar meta-atoms with tailored electromagnetic responses. They have attracted tremendous attention owing to their ability to freely control the propagation of electromagnetic waves. With active elements incorporated into metasurface designs, one can realize tunable and reconfigurable metadevices with functionalities controlled by external stimuli, opening up a new platform to dynamically manipulate electromagnetic waves. In this article, we review the recent progress on tunable and reconfigurable metasurfaces, focusing on their operation principles and practical applications. We describe the approaches to the engineering of reconfigurable metasurfaces categorized into different classes based on the available active materials or elements, which can offer uniform manipulations of electromagnetic waves. We further summarize the recent achievements on programmable metasurfaces with constitutional meta-atoms locally tuned by external stimuli, which can dynamically control the wavefronts of electromagnetic waves. Finally, we discuss time-modulated metasurfaces, which are meaningful to exploit the temporal dimension by applying a dynamic switching of the coding sequence. The review is concluded by our outlook on possible future directions and existing challenges in this fast developing field.show less
We experimentally built a photonics-aided long-distance large-capacity millimeter-wave (mm-wave) wireless transmission system and demonstrated a delivery of 40-Gbit/s W-Band 16-ary quad
We experimentally built a photonics-aided long-distance large-capacity millimeter-wave (mm-wave) wireless transmission system and demonstrated a delivery of 40-Gbit/s W-Band 16-ary quadrature amplitude modulation (QAM) signal over 4600-m wireless distance at 88.5GHz. Advanced offline digital signal processing (DSP) algorithms are proposed and employed for signal recovery, which makes the bit-error ratio (BER) under 2.4×10-2. To our best knowledge, this is the first field-trial demonstration of >4-km W-band 16QAM signal transmission, and the result achieves a record-breaking product of wireless transmission capacity and distance, i.e., 184-Gbit/s·km, for high-speed and long-distance W-band wireless communication. show less
We design and fabricate an unbalanced Mach-Zehnder interferometer (MZI) via electron beam lithography and inductively coupled plasma etching on lithium niobate thin film. ,The single un
We design and fabricate an unbalanced Mach-Zehnder interferometer (MZI) via electron beam lithography and inductively coupled plasma etching on lithium niobate thin film. ,The single unbalanced MZI exhibits a maximum extinction ratio of 32.4 dB and a low extra loss of 1.14 dB at the telecommunication band. Furthermore, tunability of the unbalanced MZI by harnessing the thermo-optic and electro-optic effect is investigated, achieving a linear tuning efficiency of 42.8 pm/℃ and 55.2 pm/V, respectively. The demonstrated structure has applications for sensing and filtering in photonic integrated circuits. show less