Advanced Photonics Research最新文献

Computer-Generated Holography

In article number 2400164, Zilong Zhang, Hongzhi Yang, and co-workers propose a new optical method based on self-interference to completely decompose the eigenmode spectrum of complex structured light. A diffractive optical method is designed and validated to extract the complete information of complex structured light fields composed with eigenmode superposition states, including the order of eigenmode, amplitude weight coefficient, and relative phase delay.

Light-Stimulated Artificial Synapses

The cover image is an attractive combination of advanced semiconductor technology and biology. The photos of biological synapses are placed on top of the chip that is displayed at the center and lower part. This implies the intersection of computing and neuroscience, in line with the research on developing photonic synapses using GaN materials. More information can be found in article number 2400146 by Xiaoqin Yang, Bingcheng Luo, Hong Gu, and co-workers.

The conventional von Neumann architecture is increasingly losing the capacity to satisfy the urgent demand for high-speed parallel computing, energy efficiency, and ultralow power consumption owing to the rapid growth of information. Brain-inspired neuromorphic computing presents an opportunity to overcome the inherent limitations of conventional computers. In recent years, photoelectric neuromorphic devices have garnered significant attention for their potential applications in brain–machine interfaces, intelligent sensing, and neuromorphic computing. Herein, a simple two-terminal light-stimulated synaptic device is fabricated using GaN thin films through metal-organic chemical vapor deposition. The device demonstrates the ability to mimic various biological synaptic functions, including learning-experience behavior, the transition from short-term to long-term memory, paired-pulse facilitation, and visual recognition and memory. In this research, an effective strategy for developing photonic synapses using GaN-based materials in neuromorphic computing and bio-realistic artificial intelligence systems is presented.

Optical Switches

In article number 2400118, Yuexin Yin and co-workers fabricate a 1 × N generalized Mach-Zehnder interferometer (GMZI) based switch on a polymer platform. This scalable structure is realized for 1 × 2, 1 × 3, and 1 × 4 switches. With phase compensations introduced, for the 1 × 4 switch, the bandwidth is 13 times larger for 10 dB crosstalk. Moreover, the all-logic optical switch is demonstrated based on the switch proposed.

Holographic Optical Elements

In article number 2400152, Jisoo Hong and co-workers present a holographic optical element (HOE) printer, which produces consistent shapes of hogels across various focal conditions, and aberration-corrected results by a printed HOE. The hogels, recorded by the interference of two beams, are printed sequentially with optimized gratings.

A single micrometer-size spherical colloid has been set in rotation by transfer of light orbital angular momentum. This particle is floating at an air–water interface. Steady-state rotational frequencies of the order of one hertz have been observed, depending on the topological charge of the beam and on its power, in agreement with expected values. The detection is performed using the rotational Doppler shift of the diffused light. Two time constants have been evidenced in the rotational velocity dynamics. The first one is related to the friction of the colloid with the fluid (air and water), whereas the other one is principally associated with the wall friction of the air–liquid interface with the container. This measurement technique makes it possible to identify dynamic parameters of the rotational movement of any spherical object, which is usually impossible to detect.

Optical Convolutional Neural Networks

In article number 2400108, Weiwei Tan, Jiale He, Guanhai Li, Xiaoshuang Chen, and co-workers propose an optical neural network that leverages GST-based microring waveguides for on-chip computing, offering 64 levels of transmission contrast with 6-bit resolution. It achieves high accuracy in image edge detection and recognition with potential for large-scale photonic neural networks.

Metalens THz Emitter

In article number 2400125, Hyunseung Jung, Oleg Mitrofanov, and co-workers present a metalens for achieving focused terahertz (THz) beam generation using InAs nanoscale resonators. This metalens enables binary-phase THz pulse generation under ultrafast near-IR pump excitation, paving the way for a flexible and compact THz generation platform for applications in imaging, spectroscopy and communications.

The luminescent solar concentrator (LSC) can function as an electricity-generating window whose performance is hindered by an inherent trade-off between power conversion efficiency and visible light transmission. To optimize this trade-off, a numerical algorithm is used to find the power conversion efficiency of 92 luminophores, ensuring an average visible transmission >55% and a color rendering index >70. Furthermore, double- and triple-stacked LSC configurations and single LSCs with two- or three-embedded luminophores are optimized. All tested LSC configurations are found to be limited to a power conversion efficiency of around 1% for window-appropriate transparencies.

Analyzing or probing a complex-structured light field with a simple model to obtain its mode composition sequence and phase delays among eigenmodes is challenging. Currently, there are numerous methods for calculating the weight and analyzing the amplitude of structured light eigenmodes, particularly on orbital angular momentum light field. However, the complete mode spectrum decomposition including the eigenmodes’ indexes with the intensity coefficients and relatively phase delays still needs the comprehensive solution. In this work, the diffractive optical method to extract the complete information of complex-structured light field composed by eigenmodes superimposed state is detailly designed and proved. Through the interference between the inverse conversion of eigenmodes in the Fourier domain, complete mode spectrum can be constructed with eigenmode ordinals, amplitude weight coefficients, and relative phases. To the best of the knowledge, this marks the inaugural use of a simple computational hologram method to fully decompose the mode spectrum information, thereby obtaining more crucial intrinsic information about the intermode phases without additional efforts. This approach on analyzation and description can serve as a vital general tool for analyzing the intensity, phase, and Poynting vector field of complex-structured light fields.