Advanced Photonics 5th Anniversary Forum
On the Cover: A comparison of cross-correlation based and phase-correlation based image registration algorithms for optical coherence tomographic angiography
On the Cover: On-chip source-device-independent quantum random number generator
On the Cover: Grating-free autofocus for single-pixel microscopic imaging
On the Cover:  Silicon photonic spectrometer with multiple customized wavelength bands

Large field of view is highly demanded for disease diagnosis in clinical applications of optical coherence tomography (OCT) and OCT angiography (OCTA) imaging. Due to the limits on optical scanning range, scanning speed, or data processing speed, only a relatively small region could be acquired and processed for most of current clinical OCT systems at one time, and generate a mosaic image of multiple adjacent small-region images with registration algorithms for disease analysis. In this work, we propose a dual-cross-correlation based translation and rotation registration (DCCTRR) algorithm for wild range OCTA imaging, which performs cross-correlation in both polarcoordinate images and Cartesian-coordinate images to calculate rotation and translation difference respectively. The performance of the proposed method is compared to standard Fourier-Merlin-transform algorithm and the results quantitatively demonstrate that the proposed method is able to align OCTA images with a lower overlap-rate, which could improve the scanning efficiency of large-scale imaging in clinical applications

Device-Independence is the ultimate goal of the realistic security of quantum information, but violating Bells inequality is difficult and complex. We have implemented the first on-chip SDI-QRNG in the whole DI/SDI field, paving the way for large-scale secure utilization of quantum resources at room temperature.

An ultrafast autofocus method for microscopy by Fourier single-pixel imaging via maximizing frequency component magnitude. It is imaging-free and is derived from the physical mechanism, making it highly attractive for autofocusing transparent samples under non-visible illumination.

Silicon photonic spectrometer with multiple customized wavelength-bands incorporated with wideband/narrowband optical filters shows great potential for various applications, including gas monitors, wearable biosensors, portable spectral-domain optical coherence tomography and so on.

AI Highlights
Ultra-robust imaging restoration of intrinsic deterioration in graded-index imaging systems enabled by classified-cascaded convolutional neural networks
Endoscopy, as a visual extension of surgical doctors, has been widely used since World War II. Nowadays, a new generation of endoscopic imaging system combining gradient refractive index (GRIN) waveguide and convolutional neural network (CNN) image restoration technology is a new idea for achieving small-diameter, low heat rigid endoscopes. However
Advanced Imaging
  • Oct. 08, 2024
  • Vol. 1, Issue 2 (2024)
Community-Publication
Tracking plasma progression in a picosecond: Physicists develop ultra-fast laser method to study high-density plasmas
Hiroshi Sawada, an associate professor in the Department of Physics at the University of Nevada, Reno, along with his colleagues at several international institutions, has developed a method to track how material heats and cools after a laser pulse has been fired.
High Power Laser Science and Engineering
  • Sep. 25, 2024
  • Vol. , Issue (2024)
Community-News
LLE Research Team Wins 2024 John Dawson Award for Excellence in Plasma Physics Research
The American Physics Society (APS) just awarded a research team from the Laboratory for Laser Energetics (LLE) with the John Dawson Award for Excellence in Plasma Physics Research.
High Power Laser Science and Engineering
  • Sep. 25, 2024
  • Vol. , Issue (2024)
Community-News
Lan Gao wins a DOE $2.75 million early career award to develop innovative diagnostic tools for future fusion energy devices
Princeton Plasma Physics Laboratory (PPPL) research physicist Lan Gao has received a 2024 Early Career Research Program (ECRP) award from the U.S. Department of Energy (DOE) to develop the next generation of diagnostic tools that will provide precise measurements for fusion experiments and future fusion pilot plants.
High Power Laser Science and Engineering
  • Sep. 25, 2024
  • Vol. , Issue (2024)
On the Cover
All-optical nanoscale Thermometry with Silicon Carbide Color Centers
In recent years, there have been significant advancements in nanoscale optical thermometry techniques, particularly in key technological fields such as materials science, biophotonics, and semiconductor engineering. These technologies enable precise temperature detection at the microscopic scale, which is of tremendous value for both scientific res
Photonics Research
  • Sep. 20, 2024
  • Vol. 12, Issue 8 (2024)
Newest Articles
Harnessing optical imaging limit through atmospheric scattering media

Recording and identifying faint objects through atmospheric scattering media by an optical system are fundamentally interesting and technologically import

Recording and identifying faint objects through atmospheric scattering media by an optical system are fundamentally interesting and technologically important. We introduce a comprehensive model that incorporates contributions from target characteristics, atmospheric effects, imaging systems, digital processing, and visual perception to assess the ultimate perceptible limit of geometrical imaging, specifically the angular resolution at the boundary of visible distance. The model allows us to reevaluate the effectiveness of conventional imaging recording, processing, and perception and to analyze the limiting factors that constrain image recognition capabilities in atmospheric media. The simulations were compared with the experimental results measured in a fog chamber and outdoor settings. The results reveal good general agreement between analysis and experiment, pointing out the way to harnessing the physical limit for optical imaging in scattering media. An immediate application of the study is the extension of the image range by an amount of 1.2 times with noise reduction via multiframe averaging, hence greatly enhancing the capability of optical imaging in the atmosphere.show less

  • Oct.17,2024
  • Advanced Photonics Nexus,Vol. 3, Issue 6
  • 066004 (2024)
Superfine multiresonant fiber grating sensors assisted with silica capillaries

We propose and demonstrate a superfine multiresonant fiber grating sensor characterized by superior spectral resolution and enhanced sensing capabilities.

We propose and demonstrate a superfine multiresonant fiber grating sensor characterized by superior spectral resolution and enhanced sensing capabilities. This sensor can be easily constructed by inserting a tilted fiber Bragg grating (TFBG) probe into a silica capillary filled with a refractive index (RI) matching oil. As the fiber cladding, the RI-matching oil, and the capillary all have the same RI, the cladding modes excited by the TFBG can extend into the RI-matching oil and capillary, facilitating surface sensing outside the capillary. Our study shows that the number of cladding modes increases and the resonance spectrum becomes denser as the outer diameter of the capillary gets larger. As a result, the detection accuracy of RI based on mode cutoff wavelength identification can be improved. Particularly, with a capillary diameter of 1 mm, the heightened spectral density enhances refractometric accuracy by nearly an order of magnitude compared to the intrinsic TFBG. The superfine multiresonant fiber grating sensor proposed here is flexible in configuration and easy to fabricate, providing a new strategy for developing new fiber sensing devices.show less

  • Oct.17,2024
  • Photonics Research,Vol. 12, Issue 11
  • 2488 (2024)
Terahertz chiral edge states enable inner-chip state transition and interchip communications over wireless terminals

Topological valley photonics has recently gained widespread interest owing to its robustness and backscattering immunity against disorders. Previous topol

Topological valley photonics has recently gained widespread interest owing to its robustness and backscattering immunity against disorders. Previous topological valley transport based on kink states required an interface between two topologically distinct domains, while recent studies have reported that chiral edge states (CESs) can be realized at the external boundary of topological insulators by changing the on-site edge potentials. However, current research on CESs is predominantly focused on the microwave frequency range, leaving challenges for emerging terahertz communications. Here, cladding-free CESs are demonstrated at the external boundary of terahertz all-silicon topological valley photonic crystals with gapless, single-mode, and linear dispersion. We show that CESs are immune to backscattering against sharp corners and support unidirectional propagation of chiral excitations. We also achieved smooth transition between kink states and CESs supported by an all-silicon platform, which could be used as the terahertz inner-chip connection. Finally, a terahertz wireless link between two disconnected CESs is verified for the near-field information interconnection between distinct mobile phones. Our work indicates CESs can improve the compactness of terahertz circuits and inspire advanced terahertz interchip communications.show less

  • Oct.17,2024
  • Chinese Optics Letters,Vol. 22, Issue 10
  • 103701 (2024)
Coevolution of nanophotonics and nanofabrication: achievements and beyond
  • Oct.16,2024
  • Photonics Insights,Vol. 3, Issue 4
  • C07 (2024)
Advanced Photonics Photonics Insights

Efficiently tracking and imaging interested moving targets is crucial across various applications, from autonomous systems to surveillance. However, persistent challenges remain in various field

Efficiently tracking and imaging interested moving targets is crucial across various applications, from autonomous systems to surveillance. However, persistent challenges remain in various fields, including environmental intricacies, limitations in perceptual technologies, and privacy considerations. In this study, we present a teacher-student learning model, generative adversarial network (GAN)-guided diffractive neural network (DNN), which performs visual tracking and imaging of the interested moving target. GAN, as a teacher model, empowers efficient acquisition of the skill to differentiate the specific target of interest in the domains of visual tracking and imaging. DNN-based student model learns to master the skill to differentiate the interested target from GAN. The process of obtaining a GAN-guided DNN starts with capturing moving objects effectively by using an event camera with high temporal resolution and low latency. Then the generative power of GAN is utilized to generate data with position-tracking capability for the interested moving target, subsequently serving as labels to the training of DNN. DNN learns to image the target during training while retaining the target's positional information. Our experimental demonstration highlights the efficacy of GAN-guided DNN in visual tracking and imaging the interested moving target. We envision the GAN-guided DNN can significantly enhance autonomous systems, and surveillance.show less

  • Oct.17,2024
  • Advanced Photonics Nexus,Vol. 3, Issue 6

Coherent optics are emerging as promising solutions for future passive optical networks. However, upstream burst-mode coherent detection faces challenges due to the need for fast digital signal

Coherent optics are emerging as promising solutions for future passive optical networks. However, upstream burst-mode coherent detection faces challenges due to the need for fast digital signal processing and its susceptibility to laser wavelength drift. To address these issues, we propose an algorithm capable of rapid channel equalization and frequency offset estimation (FOE). The feasibility of the proposed scheme is experimentally verified through 128-Gbits/s 16QAM signal transmission systems. Consequently, integrating a fine FOE tap into the AEQ allows for rapid convergence and accurate frequency offset estimates within approximately ±0.5 times the symbol rate, while maintaining low complexity.show less

  • Oct.17,2024
  • Chinese Optics Letters,Vol. 23, Issue 4
  • (2025)

The microring resonator (MRR) plays important roles in signal processing because high quality band-pass filtering can be obtained at its drop port. To promote signal to noise ratio, a high rejec

The microring resonator (MRR) plays important roles in signal processing because high quality band-pass filtering can be obtained at its drop port. To promote signal to noise ratio, a high rejection ratio is significantly demanded. However, it is still challenging to promote the rejection ratio of the MRR-based band-pass filter. To solve this problem, we propose to use an all-pass filter (APF) to enhance the rejection ratio of the MRR-based band-pass filter. Experimental results show that the improved rejection ratio is as high as 47.7 dB, which is improved by 23.6 dB compared with that of the MRR. Meanwhile, the bandwidth of the MRR-based band-pass filter is reduced from 2.61 to 1.14 GHz thanks to the constructive interference in the passband. Additionally, the center frequency of this ultra-high rejection MRR can be continuously tuned from 6.26 to 46.25 GHz. The quality(Q) of the MRR is improved from 7.4×104 to 1.7×105.During the adjustment, the rejection ratio of the band-pass filter remains exceeding 40 dB. The proposed approach can be used to achieve optical bandpass filters with high performance.show less

  • Oct.15,2024
  • Advanced Photonics Nexus,Vol. 3, Issue 6

Spectroscopy, especially for plasma spectroscopy, provided a powerful platform for biological and material analysis with their elemental and molecular fingerprinting capability. AI has the treme

Spectroscopy, especially for plasma spectroscopy, provided a powerful platform for biological and material analysis with their elemental and molecular fingerprinting capability. AI has the tremendous potential to build a universal quantitative framework covering all branches of plasma spectroscopy based on its unmatched representation and generalization ability. Herein, we introduce an AI-based unified method called self-supervised image-spectrum twin information fusion detection (SISTIFD) to collect twin co-occurrence signals of the plasma and to intelligently predict the physical parameters for improving the performances of all plasma spectroscopic techniques. It can fuse the spectra and plasma images in synchronization, derive the plasma parameters and provide accurate results. The experiments demonstrates its excellent utility and capacity with 98% reduction in evaluation indexes and 143 Hz of analysis frequency. Besides, as a completely end-to-end and self-supervised framework, the SISTIFD enables automatic detection without manual preprocessing or intervention. With these advantages, it remarkably enhanced various plasma spectroscopic techniques with state-of-the-art performance and unsealed their possibility in industry, especially in the regions that require both capability and efficiency. This scheme brings new inspiration to the whole field of plasma spectroscopy, and enables in-situ analysis with a real-world scenario of high throughput, cross-interference, various analyte complexity, and diverse applications.show less

  • Oct.15,2024
  • Advanced Photonics Nexus,Vol. 3, Issue 6