Dispersion-assisted high-dimensional photodetector.

Intensity, polarization and wavelength are intrinsic characteristics of light. Characterizing light with arbitrarily mixed information on polarization and spectrum is in high demand1-4. Despite the extensive efforts in the design of polarimeters5-18 and spectrometers19-27, concurrently yielding high-dimensional signatures of intensity, polarization and spectrum of the light fields is challenging and typically requires complicated integration of polarization- and/or wavelength-sensitive elements in the space or time domains. Here we demonstrate that simple thin-film interfaces with spatial and frequency dispersion can project and tailor polarization and spectrum responses in the wavevector domain. By this means, high-dimensional light information can be encoded into single-shot imaging and deciphered with the assistance of a deep residual network. To the best of our knowledge, our work not only enables full characterization of light with arbitrarily mixed full-Stokes polarization states across a broadband spectrum with a single device and a single measurement but also presents comparable, if not better, performance than state-of-the-art single-purpose miniaturized polarimeters or spectrometers. Our approach can be readily used as an alignment-free retrofit for the existing imaging platforms, opening up new paths to ultra-compact and high-dimensional photodetection and imaging.

Highly efficient and recyclable catalyst: porous Fe3O4-Au magnetic nanocomposites with tailored synthesis.

In this work, we reported the tailored design of highly efficient Fe3O4-Au magnetic nanocomposite (MNP) catalysts. Fe3O4 nanocrystals with three different morphologies have been developed with engineered amounts of urea, and the plausible mechanism has been proposed. Then by controlling the amount of Au seeds, Fe3O4-Au MNPs with different morphologies and tunable Au deposition have been realized. Characterizations including x-ray diffraction (XRD), transmission electron microscopy (TEM), Mössbauer spectra, and elemental mapping are implemented to unveil the structural and physical characteristics of the successfully developed Fe3O4-Au MNPs with different morphologies. The catalytic ability of Fe3O4-Au MNPs with different morphologies have been compared by applying them to degrading RhB and 4-NP, meanwhile the correlation between the amount of Au seeds and the turnover frequency as well as the catalytic ability of Fe3O4-Au MNPs is investigated systematically. We found that the flower-like Fe3O4-Au MNPs with 20 ml Au seeds added achieved the best degradation efficiency of 96.7%, and their catalytic ability were almost unchanged after recycling. Out study sheds the light into the tailored design of highly efficient and recyclable catalysts for RhB and 4-NP.

Fast auto-focusing search algorithm for a high-speed and high-resolution camera based on the image histogram feature function.

In this paper, we developed an auto-focus image quality evaluation function from the histogram feature function (HFF) of a high-speed camera. Based on this function, we then proposed a fast auto-focus search algorithm. We further demonstrated that the auto-focus image quality evaluation function we proposed requires fewer computational resources, while providing a more effective focusing area and more moderate sensitivity, compared to the traditional evaluation function. In contrast to the traditional climbing method, our proposed fast auto-focusing search algorithm also can spot the focus point in a shorter time, effectively reducing the round trips of the focusing motor and improving the focusing accuracy.

Improved generation method utilizing a modified Fourier spectrum for Airy beams with the phase-only filter technique.

We present an improved method to generate Airy beams utilizing a liquid crystal on silicon (LCoS) device. In this method, the phase and amplitude information of a modified Fourier spectrum of an Airy beam together with a Fresnel holographic lens is encoded onto the LCoS using the phase-only filter technique; thus, a desired Airy beam is formed in the focal plane of the Fresnel holographic lens. In this paper, the principle of the proposed method is described in detail, and both the excellent numerical simulations and experimental results for verifying this method are demonstrated. It is shown that the new generation method is accurate and simple; in particular, the setup is more compact compared to the conventional Fourier transform method, which comprises only the input polarized laser and a LCoS device. This effective method will further promote investigations into the properties and applications of Airy beams.

Light People: Prof. Eric Mazur speaks about ultrafast optics and education.

EDITORIAL: Prof. Eric Mazur is a great influencer over and beyond the optics community. As a physicist, he is a pioneer of ultrafast optics and was one of the inventors of colliding-pulse mode-locked laser. As an educator, he not only gave talks to thousands, but also revolutionized teaching with his globally renowned methodology "Peer Instruction". As a leader and entrepreneur, he co-founded several companies and was President of Optica (formerly the Optical Society) and currently is the Chair of the Optica Foundation. Here, Light: Science & Applications talked with Prof. Eric Mazur about his opinions on research, education and industry. The full interview video can be found in the Supplementary File.

Light People: Prof. Kei May Lau, newly elected US NAE member in Hong Kong, talks about future of photonics and women in science.

EDITORIAL: Photonics technology remains a driving force in today's scientific landscape, marked by continuous innovation and cross-disciplinary relevance. In an enlighting conversation with Light: Science & Applications, Prof. Kei May Lau, a pioneer in photonics research, shares her deep insights on the evolution of technologies of LEDs, lasers, challenges of hetero-epitaxy, and the future of micro-LEDs and quantum dot lasers. Recently honored as a member of the US National Academy of Engineering (NAE) for her significant contributions to photonics and electronics using III-V semiconductors on silicon, Prof. Lau stands out as the sole Hong Kong scholar inducted into the NAE this year, joining 114 new and 21 international members. In this exclusive Light People interview, Prof. Lau shares her journey as a pioneering woman in engineering, her commitment to mentorship and academia, and her perspective on advancing female representation in science. The summary provided is distilled from Prof. Lau's thoughtful responses during the interview. For a deeper exploration of Prof. Lau's experiences and advice, the full interview is available in the Supplementary material.

Light people: Prof. Evelyn Hu's adventure: from semiconductors to quantum - from industry to academia.

EDITORIAL: As part of our Light People series, we are delighted to have invited Prof. Evelyn Hu, a highly accomplished scientist from Harvard University, to share with us her personal journey. Prof. Hu's remarkable contributions in both academia and industry have taken her from industry giants to academia's most prestigious institutions, traversing various research frontiers that have played a critical role in the ongoing digital revolution. Through this interview, we aim to offer the Light community valuable insights into nanophotonics, quantum engineering, and Prof. Hu's research methodology and life philosophy, while also celebrating her outstanding achievements as a female role model. Ultimately, our goal is to inspire more women to pursue careers in this important and rapidly expanding field, which has a profound impact on all sectors of society. The following is a summary of an interview with Professor Evelyn Hu, available in the Supplementary Information.

Light People: Prof. Sir John Pendry, father of metamaterials, spoke about the future of meta.

EDITORIAL: When consulting with the Marconi company in 1995, Prof. Sir John Pendry uncovered exotic structures that gave negative permittivity and negative permeability, respectively. In 1999, Prof. Pendry introduced split ring resonators (SRRs), and later in 2000, Prof. David Smith and Prof. Sheldon Schultz experimentally showed that periodic array of SRRs and continuous wires previously proposed by Prof. Pendry could exhibit simultaneously negative values of effective permeability and permittivity at the same frequency. Shortly after, Prof. Pendry revealed that a slab of material with simultaneous negative permittivity and permeability could challenge the Abbé diffraction limit on traditional lenses and focus all Fourier components of a point object onto a perfect image, leading to a "perfect lens". The vision of a perfect lens attracted extensive research interest and opened a new field which was later widely known as metamaterials. Now two decades on, the explosion of metamaterials has revolutionized numerous researches in physics, materials science, chemistry, and engineering. To shed light on the research direction of metamaterials, Light: Science & Applications invited Sir John Pendry, father and living legend of metamaterials, to speak about the future of metamaterials. The original interview can be accessed in Supplementary video.

Light People: Professor Xianfeng Chen spoke about integrated photonics.

EDITORIAL: In 1969, Stewart E. Miller published "Integrated optics: an introduction", which outlined a proposal for a miniature form of laser beam circuitry, marking the first research paper about what is now known as integrated photonics. Now half a century has passed, integrated photonics grew robustly from integrating a limited number of devices and functions towards versatile and industrialized photonic integrated circuits. In this interview, Light: Science & Applications invited Prof. Xianfeng Chen [see the "Short Bio" section] to share his insight about the past, present and future of integrated photonics.

Light people: Professor Perry Shum spoke about fiber-enabled industries.

EDITORIAL: Fiber technologies have fundamentally reshaped the way we see, the way we sense, the way we communicate, and the way we live. They were so well developed that in some industries such as telecommunication, they were even taken for granted. For that, Light: Science & Applications invited Professor Perry Shum, a pioneer in fiber technologies and their industrialization, to speak about what chances fiber technologies can bring to industries.

Light People: Prof. John Bowers spoke about silicon photonics.

EDITORIAL: Silicon photonics is advancing rapidly with many scientific and engineering advances and many new applications for photonics. To highlight the topic, Light: Science & Applications invited John Bowers, director of the Institute for Energy Efficiency and distinguished professor from the University of California, Santa Barbara, to talk about the fundamentals and industries, and give a future perspective of silicon photonics. The below is summarized from the video interview of Prof. Bowers. The original interview can be accessed in Supplementary video.

Light People: Professor John Dudley spoke about supercontinuum generation and International Day of Light.

EDITORIAL: The extreme spectral broadening of light in supercontinuum generation (SCG) is considered by many as the ultimate legacy of nonlinear optics. In this interview, Light: Science & Applications invited John Dudley [see the "Short Bio" section]-pioneer of supercontinuum generation, rogue waves, and ultrafast lasers-to share insight on how supercontinuum generation have evolved over the past decades and where it is heading. Also as the Steering Chair of UNESCO's International Day of Light & International Year of Light (IDL & IYL), John is asked to share his comments on how light may influence post-pandemic World.

A Novel Au@Cu2O-Ag Ternary Nanocomposite with Highly Efficient Catalytic Performance: Towards Rapid Reduction of Methyl Orange Under Dark Condition.

Au@Cu2O core-shell nanocomposites (NCs) were synthesized by reducing copper nitrate on Au colloids with hydrazine. The thickness of the Cu2O shells could be varied by adjusting the molar ratios of Au: Cu. The results showed that the thickness of Cu2O shells played a crucial role in the catalytic activity of Au@Cu2O NCs under dark condition. The Au@Cu2O-Ag ternary NCs were further prepared by a simple galvanic replacement reaction method. Moreover, the surface features were revealed by TEM, XRD, XPS, and UV-Vis techniques. Compared with Au@Cu2O NCs, the ternary Au@Cu2O-Ag NCs had an excellent catalytic performance. The degradation of methyl orange (MO) catalyzed by Au@Cu2O-Ag NCs was achieved within 4 min. The mechanism study proved that the synergistic effects of Au@Cu2O-Ag NCs and sodium borohydride facilitated the degradation of MO. Hence, the designed Au@Cu2O-Ag NCs with high catalytic efficiency and good stability are expected to be the ideal environmental nanocatalysts for the degradation of dye pollutants in wastewater.