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.

Editors' Picks
Surface Laser Traps: Pioneering Optical Tools for Advanced Particle Manipulation
Optical forces are crucial in understanding light–matter interactions across various scientific fields, including atomic physics, optics, photonics, and nanotechnology. Since the advent of laser tweezers, significant advancements have been made in optical trapping, binding, sorting, and transporting particles using optical forces. Current research
Photonics Research
  • Dec. 05, 2024
  • Vol. 12, Issue 10 (2024)
Community-News
6th European Conference on Plasma Diagnostics
The 6th European Conference on Plasma Diagnostics of the Conference will be held in Prague, Czechia (April 7th - 10th 2025) and organised by the Institute of Plasma Physics of the Czech Academy of Sciences.
High Power Laser Science and Engineering
  • Dec. 04, 2024
  • Vol. , Issue (2024)
Community-Publication
Squeeze it!
Scientists at the European XFEL and DESY produce high-power attosecond X-ray pulses at megahertz repetition rates
High Power Laser Science and Engineering
  • Dec. 04, 2024
  • Vol. , Issue (2024)
Community-Publication
Reconstructing multi-spectral wavefronts from measured speckle patterns
Lead by Slava Smartsev of LOA's APPLI group and Aaron Liberman of the Weizmann Institute of Science, Israel, a novel and technically straightforward approach has been developed for the measurement of the spectrally resolved wavefront of an ultrashort laser pulse.
High Power Laser Science and Engineering
  • Dec. 04, 2024
  • Vol. , Issue (2024)
AP Highlights
Metalenses harness AI for superior performance
Modern imaging systems, such as those used in smartphones, virtual reality (VR), and augmented reality (AR) devices, are constantly evolving to become more compact, efficient, and high-performing. Traditional optical systems rely on bulky glass lenses, which have limitations like chromatic aberrations, low efficiency at multiple wavelengths, and la
Advanced Photonics
  • Nov. 28, 2024
  • Vol. 6, Issue 6 (2024)
Newest Articles
Performance enhancement in the long-wavelength low-gain region of Ti:sapphire lasers by an efficient stimulated Raman scattering process

We demonstrated a method to improve the output performance of a Ti:sapphire laser in the long-wavelength low-gain region with an efficient stimulated Rama

We demonstrated a method to improve the output performance of a Ti:sapphire laser in the long-wavelength low-gain region with an efficient stimulated Raman scattering process. By shifting the wavelength of the high-gain-band Ti:sapphire laser to the long-wavelength low-gain region, high-performance Stokes operation was achieved in the original long-wavelength low-gain region of the Ti:sapphire laser. With the fundamental wavelength tuning from 870 to 930 nm, first-order Stokes output exceeding 2.5 W was obtained at 930–1000 nm, which was significantly higher than that directly generated by the Ti:sapphire laser, accompanied by better beam quality, shorter pulse duration and narrower linewidth. Under the pump power of 42.1 W, a maximum first-order Stokes power of 3.24 W was obtained at 960 nm, with a conversion efficiency of 7.7%. Furthermore, self-mode-locked modulations of first- and second-order Stokes generation were observed in Ti:sapphire intracavity solid Raman lasers for the first time.show less

  • Dec.03,2024
  • High Power Laser Science and Engineering,Vol. 12, Issue 6
  • 06000e71 (2024)
Artificial-gauge-field-based inverse design for wideband-flat power splitter and microring resonator

A power splitter with a wideband arbitrary splitting ratio, which provides flexibility and adaptability in forming photonic devices such as microring reso

A power splitter with a wideband arbitrary splitting ratio, which provides flexibility and adaptability in forming photonic devices such as microring resonators and Mach–Zehnder interferometers, proves to be essential in photonic integrated circuits (PICs). We designed and fabricated a directional coupler-based power splitter with a wideband arbitrary splitting ratio and a microring resonator with a wideband uniform extinction ratio (ER) based on artificial gauge field (AGF) optimization. The neural network-aided inverse design method is applied to complete the target. Less than 0.9 dB power splitting variation and 1.6 dB ER variation have been achieved experimentally over a 100-nm bandwidth. Wideband performance, design efficiency, and device compactness are obtained by utilizing this optimization, which indicates great potential and universality in PIC applications.show less

  • Dec.03,2024
  • Advanced Photonics Nexus,Vol. 4, Issue 1
  • 016001 (2025)
Single-molecule characterization from the perspective of optics, photonics, and optoelectronics: a review

A single molecule is the building block of the material world and the smallest independently stable unit. Exploring single-molecule properties using optic

A single molecule is the building block of the material world and the smallest independently stable unit. Exploring single-molecule properties using optical, photonic, and optoelectronic techniques holds great scientific significance in revealing the molecular dynamics, molecular structures, and molecular quantum properties. Nano-optical techniques, such as single-molecule photoluminescence and Raman scattering, not only enable a comprehensive analysis of interactions and conformational dynamics through spectral analysis but also provide unparalleled insights into elucidating the intricate structure of single molecules through atomic-resolution imaging. The research of photonics based on single-molecule electroluminescence has brought new ideas and limitless possibilities to the design and manufacture of photonic information devices. Single-molecule optoelectronics, which leverages photoexcitation to modulate electrical properties, has significant contributions to elucidating charge transport characteristics and optimizing the optoelectronic functions realized by single-molecule devices. Moreover, the optoelectronic characterization based on the interaction of ultrafast optical pulses with single molecules provides unprecedented opportunities for exploring their dynamic behavior and regulation laws on ultrafast time scales. We provide a timely and comprehensive overview of the latest significant advancements pertaining to the optical, photonic, and optoelectronic properties of single molecules, thereby presenting a fresh perspective for research across diverse fields, including single-molecule photophysics and photochemistry.show less

  • Dec.02,2024
  • Advanced Photonics,Vol. 6, Issue 6
  • 064002 (2024)
Parity effects in Rydberg-state excitation in intense laser fields

Conservation of parity plays a fundamental role in our understanding of various quantum processes. However, it is difficult to observe in atomic and molec

Conservation of parity plays a fundamental role in our understanding of various quantum processes. However, it is difficult to observe in atomic and molecular processes induced by a strong laser field due to their multiphoton character and the large number of states involved. Here we report an effect of parity in strong-field Rydberg-state excitation (RSE) by comparing the RSE probabilities of the N2 molecule and its companion atom Ar, which has a similar ionization potential but opposite parity of its ground state. Experimentally, we observe an oscillatory structure as a function of intensity with a period of about 50 TW/cm2 in the ratio between the RSE yields of the two species, which can be reproduced by simulations using the time-dependent Schrödinger equation (TDSE). We analyze a quantum-mechanical model, which allows for interference of electrons captured in different spatial regions of the Rydberg-state wave function. In the intensity-dependent RSE yield, it results in peaks with alternating heights with a spacing of 25 TW/cm2 and at the same intensity for both species. However, due to the opposite parities of their ground states, pronounced RSE peaks in Ar correspond to less pronounced peaks in N2 and vice versa, which leads to the period of 50 TW/cm2 in their ratio. Our work reveals a novel parity-related interference effect in the coherent-capture picture of the RSE process in intense laser fields.show less

  • Dec.02,2024
  • Photonics Research,Vol. 12, Issue 12
  • 3033 (2024)
Advanced Photonics Photonics Insights

Spatiotemporal optical wavepackets refer to light fields with sophisticated structures in both space and time. The ability to produce such spatiotemporally structured optical wavepackets on dema

Spatiotemporal optical wavepackets refer to light fields with sophisticated structures in both space and time. The ability to produce such spatiotemporally structured optical wavepackets on demand attracted rapidly increasing interests as it may unravel a variety of fundamental physical effects and applications. Traditionally, pulsed laser fields are treated as spatiotemporally separable waveform solutions to Maxwell’s equations. Recently more generalized spatiotemporally non-separable solutions have gained attention due to their remarkable properties. This review aims to provide essential insights into sculpting light in the space-time domain to create customized spatiotemporal structures and highlights the recent advances in the generation, manipulation, and characterization of increasingly complex spatiotemporal wavepackets. These spatiotemporally non-separable light fields with diverse geometric and topological structures exhibit unique physical properties during propagation, focusing, and light-matter interactions. Various novel results and their broad potential applications as well as outlook for future trends and open challenges in this field are presented.show less

  • Dec.06,2024
  • Photonics Insights

This paper presents a QPSK phase recovery algorithm for coherent inter-satellite optical wireless communication (IsOWC). From theoretical perspective, we explain the process of the multiplier-fr

This paper presents a QPSK phase recovery algorithm for coherent inter-satellite optical wireless communication (IsOWC). From theoretical perspective, we explain the process of the multiplier-free algorithm. Through simulations, we analyze key parameters and provide guidances on their optimal selection. Additionally, proposed algorithm maintains stable phase tracking at Eb/N0 as low as 4 dB. In ob2b transmission test, our algorithm achieved a sensitivity of -49 dBm @5 Gbps QPSK (HD-FEC limit). Compared to the V&V algorithm, its receiving sensitivity is improved by 1 dB, resulting in a link distanceextension of 1100 km. Our multiplier-free and robust algorithm meets the requirements of IsOWC systems and shows promise for future applications.show less

  • Dec.06,2024
  • Chinese Optics Letters,Vol. 23, Issue 5
  • (2025)

Supercontinuum sources on silicon have made significant progress in the past decades. However, conventional approaches to broaden the spectral bandwidth often rely on complex and critical disper

Supercontinuum sources on silicon have made significant progress in the past decades. However, conventional approaches to broaden the spectral bandwidth often rely on complex and critical dispersion engineering by optimizing the core thickness or introducing the cladding with special materials and structures. In this work, we propose and demonstrate the supercontinuum generation using long-period-grating (LPG) waveguides on silicon with a C-band pump. The LPG waveguide is introduced for quasi phase matching and the generated supercontinuum spectrum is improved greatly with grating-induced dispersive waves. In addition, the demonstrated LPG waveguide shows a low propagation loss comparable to regular silicon photonic waveguides without gratings. In experiments, when using a 1550-nm 75-fs pulse pump with a pulse energy of 200 pJ, the supercontinuum spectrum generated with the present LPG waveguide shows an ultra-broad extend from 1150 nm to 2300 nm, which is much wider by 200 nm than that achieved by dispersion-engineered uniform silicon photonic waveguides on the same chip, providing a promising option for on-chip broadband light source for silicon photonic systems.show less

  • Dec.05,2024
  • Advanced Photonics Nexus,Vol. 4, Issue 1

In few-mode erbium-doped fiber (FM-EDF), which is key sections in space division multiplexing (SDM) communication system, linearly polarized (LP) and orbital angular momentum (OAM) mode as two m

In few-mode erbium-doped fiber (FM-EDF), which is key sections in space division multiplexing (SDM) communication system, linearly polarized (LP) and orbital angular momentum (OAM) mode as two mode bases with different phase profile can be transformed into each other. In principle, the LP and OAM modes have different mode spatial intensity distribution and a gain difference for FM-EDF amplifier. How to analyze and characterize the differential mode-bases gain (DMBG) is important but still an issue. Here, we build for the first time a local analysis model composed of discrete elements of the FM-EDF cross-section in mode spatial intensity distribution azimuthal variations areas. Using the model to the two mode-bases, the analysis of local particle number distribution and the description of local gain difference in detail are realized, and the overall gain difference between the two mode bases is obtained. By building an amplifier system based on mode phase profile controlling, the gain of two mode-bases is characterized experimentally. The measured DMBG is about 0.8dB in the second-order mode, which is consistent with the simulation result. This result provides a potentially way to reduce the difference mode gain in FM-EDF which is important in improving the performance of SDM communication system.show less

  • Dec.05,2024
  • Advanced Photonics Nexus,Vol. 4, Issue 1