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Spectrometers with ever-smaller footprints are sought after for a wide range of applications in which minimized size and weight are paramount, including emerging in situ characterization techniques. We report on an ultracompact microspectrometer design based on a single compositionally engineered nanowire. This platform is independent of the complex optical components or cavities that tend to constrain further miniaturization of current systems. We show that incident spectra can be computationally reconstructed from the different spectral response functions and measured photocurrents along the length of the nanowire. Our devices are capable of accurate, visible-range monochromatic and broadband light reconstruction, as well as spectral imaging from centimeter-scale focal planes down to lensless, single-cell–scale in situ mapping.

Chemically synthesized metal nanowires are promising building blocks for next-generation photonic integrated circuits, but technological implementation in monolithic integration will be severely hampered by the lack of controllable and precise manipulation approaches, due to the strong adhesion of nanowires to substrates in non-liquid environments. Here, we demonstrate this obstacle can be removed by our proposed earthworm-like peristaltic crawling motion mechanism, based on the synergistic expansion, friction, and contraction in plasmon-driven metal nanowires in non-liquid environments. The evanescently excited surface plasmon greatly enhances the heating effect in metal nanowires, thereby generating surface acoustic waves to drive the nanowires crawling along silica microfibres. Advantages include sub-nanometer positioning accuracy, low actuation power, and self-parallel parking. We further demonstrate on-chip manipulations including transporting, positioning, orientation, and sorting, with on-situ operation, high selectivity, and great versatility. Our work paves the way to realize full co-integration of various functionalized photonic components on single chips. Implementing metal nanowires in photonic circuits is challenging due to lack of suitable manipulation techniques. Here, the authors present an earthworm-like peristaltic crawling motion mechanism, based on surface plasmons and surface acoustic waves, and show on-chip manipulations of single nanowires.

Miniaturized spectrometers are of immense interest for various on-chip and implantable photonic and optoelectronic applications. State-of-the-art conventional spectrometer designs rely heavily on bulky dispersive components (such as gratings, photodetector arrays, and interferometric optics) to capture different input spectral components that increase their integration complexity. Here, we report a high-performance broadband spectrometer based on a simple and compact van der Waals heterostructure diode, leveraging a careful selection of active van der Waals materials- molybdenum disulfide and black phosphorus, their electrically tunable photoresponse, and advanced computational algorithms for spectral reconstruction. We achieve remarkably high peak wavelength accuracy of ~2 nanometers, and broad operation bandwidth spanning from ~500 to 1600 nanometers in a device with a ~ 30×20 μm 2 footprint. This diode-based spectrometer scheme with broadband operation offers an attractive pathway for various applications, such as sensing, surveillance and spectral imaging. Here, the authors report a high-performance broadband spectrometer based on a van der Waals heterostructure tunnel diode containing MoS 2 and and black phosphorus, leveraging their electrically tunable photoresponse and advanced computational algorithms for spectral reconstruction.

Black phosphorus is a two-dimensional material of great interest, in part because of its high carrier mobility and thickness dependent direct bandgap. However, its instability under ambient conditions limits material deposition options for device fabrication. Here we show a black phosphorus ink that can be reliably inkjet printed, enabling scalable development of optoelectronic and photonic devices. Our binder-free ink suppresses coffee ring formation through induced recirculating Marangoni flow, and supports excellent consistency (< 2% variation) and spatial uniformity (< 3.4% variation), without substrate pre-treatment. Due to rapid ink drying (< 10 s at < 60 °C), printing causes minimal oxidation. Following encapsulation, the printed black phosphorus is stable against long-term (> 30 days) oxidation. We demonstrate printed black phosphorus as a passive switch for ultrafast lasers, stable against intense irradiation, and as a visible to near-infrared photodetector with high responsivities. Our work highlights the promise of this material as a functional ink platform for printed devices. Atomically thin black phosphorus shows promise for optoelectronics and photonics, yet its instability under environmental conditions and the lack of well-established large-area synthesis protocols hinder its applications. Here, the authors demonstrate a stable black phosphorus ink suitable for printed ultrafast lasers and photodetectors.

3D in-substrate integration of optical functionalities fully utilizes the vertical dimension of space and is valuable for advancing next-generation integrated optoelectronics. However, as a key optical effect, optical dispersion remains unavailable to be tailored at the microscale in 3D. We introduce artificial dispersive microregions in lithium niobate crystals to engineer free-space ultra-broadband optical dispersion. The microregions are formed by ultrafast laser-induced sub-wavelength phase-transition nanostripes, which modulate the crystal’s birefringence to establish localized frequency-dependent interference of ordinary and extraordinary light. This approach operates across an ultra-broad wavelength range (>1300 nm) within an exceptionally compact volume (50 × 10 × 6 µm³), and allows for precise, on-demand dispersion control in 3D space. The dispersive microregions exhibit viewing-angle independence, stability to harsh conditions (600 °C high temperature, contamination, corrosion, and mechanical damage), and wide applicability across various birefringent crystals. We demonstrate the versatility of our method in developing broadband on-chip micro-spectrometers and applications of spectral imaging, information recording, and encryption. The authors demonstrate ultra-broadband microscale optical dispersion in LiNbO 3 crystals, enabling precise and robust on-demand dispersion engineering in free space, with strong potential for applications in informatics and spectroscopy.

Miniaturized spectrometers have significantly advanced real-time analytical capabilities in fields such as environmental monitoring, healthcare diagnostics, and industrial quality control by enabling precise on-site spectral analysis. However, achieving high sensitivity and spectral resolution within compact devices remains a significant challenge, particularly when detecting low-concentration analytes or subtle spectral variations critical for chemical and molecular analysis. This study introduces an innovative approach employing guided-mode resonance filters (GMRFs) to address these limitations. Functioning similarly to notch filters, GMRFs selectively block specific spectral bands while allowing others to pass, maximizing energy extraction from incident light and enhancing spectral encoding. Our design incorporates narrow band-stop filters, which are essential for accurate spectrum reconstruction, resulting in improved resolution and sensitivity. Our spectrometer delivers a spectral resolution of 0.8 nm over a range of 370–810 nm. It achieves sensitivity values that are more than ten times greater than those of conventional grating spectrometers during fluorescence spectroscopy of mouse jejunum. This enhanced sensitivity and resolution are particularly beneficial for chemical and biological applications, facilitating the detection of trace analytes in complex matrices. Furthermore, the spectrometer’s compatibility with complementary metal oxide semiconductor (CMOS) technology enables scalable and cost-effective production, fostering broader adoption in chemical analysis, materials science, and biomedical research. This study underscores the transformative potential of the GMRF-based spectrometer as an innovative tool for advancing chemical and interdisciplinary analytical applications.

Photonic technologies offer numerous functionalities that can be used to realize astrophotonic instruments. The most spectacular example to date is the ESO Gravity instrument at the Very Large Telescope in Chile that combines the light-gathering power of four 8 m telescopes through a complex photonic interferometer. Fully integrated astrophotonic devices stand to offer critical advantages for instrument development, including extreme miniaturization when operating at the diffraction-limit, as well as integration, superior thermal and mechanical stabilization owing to the small footprint, and high replicability offering significant cost savings. Numerous astrophotonic technologies have been developed to address shortcomings of conventional instruments to date, including for example the development of photonic lanterns to convert from multimode inputs to single mode outputs, complex aperiodic fiber Bragg gratings to filter OH emission from the atmosphere, complex beam combiners to enable long baseline interferometry with for example, ESO Gravity, and laser frequency combs for high precision spectral calibration of spectrometers. Despite these successes, the facility implementation of photonic solutions in astronomical instrumentation is currently limited because of (1) low throughputs from coupling to fibers, coupling fibers to chips, propagation and bend losses, device losses, etc, (2) difficulties with scaling to large channel count devices needed for large bandwidths and high resolutions, and (3) efficient integration of photonics with detectors, to name a few. In this roadmap, we identify 24 key areas that need further development. We outline the challenges and advances needed across those areas covering design tools, simulation capabilities, fabrication processes, the need for entirely new components, integration and hybridization and the characterization of devices. To realize these advances the astrophotonics community will have to work cooperatively with industrial partners who have more advanced manufacturing capabilities. With the advances described herein, multi-functional integrated instruments will be realized leading to novel observing capabilities for both ground and space based platforms, enabling new scientific studies and discoveries.

The burgeoning field of computational spectrometers is rapidly advancing, providing a pathway to highly miniaturized, on-chip systems for in-situ or portable measurements. The performance of these systems is typically limited in its encoder section. The response matrix is largely compromised with redundancies, due to the periodic intensity or overly smooth responses. As such, the inherent interdependence among the physical size, resolution, and bandwidth of spectral encoders poses a challenge to further miniaturization progress. Achieving high spectral resolution necessitates a long optical path length, leading to a larger footprint required for sufficient spectral decorrelation, resulting in a limited detectable free-spectral range (FSR). Here, we report a groundbreaking ultra-miniaturized disordered photonic molecule spectrometer that surpasses the resolution-bandwidth-footprint metric of current spectrometers. This computational spectrometer utilizes complicated electromagnetic coupling to determinately generate quasi-random spectral response matrices, a feature absents in other state-of-the-art systems, fundamentally overcoming limitations present in the current technologies. This configuration yields an effectively infinite FSR while upholding a high Q-factor ( > 7.74 × 10 5 ). Through dynamic manipulation of photon frequency, amplitude, and phase, a broad operational bandwidth exceeding 100 nm can be attained with an ultra-high spectral resolution of 8 pm, all encapsulated within an ultra-compact footprint measuring 70 × 50 μm². The disordered photonic molecule spectrometer is constructed on a CMOS-compatible integrated photonics platform, presenting a pioneering approach for high-performance and highly manufacturable miniaturized spectroscopy.

Hyperspectral imaging acquires spatially resolved spectral signatures, enabling a wide range of applications from scientific research to industrial processes. Traditional microelectron-mechanical systems (MEMS) Fabry–Pérot (FP) spectrometers offer a compact and simple design but are limited by single free spectral range (FSR) operation. This limitation introduces a fundamental trade-off: achieving high spectral resolution necessitates narrowing the operational bandwidth. Furthermore, maintaining such high resolution demands a larger number of sampling channels, which increases the acquisition time for a single hyperspectral image and thereby limits the frame rate. Here, we present a computational hyperspectral imaging framework that achieves broadband spectral coverage and high frame rate without sacrificing spectral resolution. By dynamically modulating the MEMS-FP cavity to span multiple FSRs, we generate a set of low-correlation spectral sampling patterns as spectral encoders. When combined with a tailored reconstruction algorithm, the system accurately decodes spectral information from a significantly reduced number of sampling channels. We experimentally validate the effectiveness of our system through LED array inspection, demonstrating its potential for high-throughput defect detection in LEDs or screen manufacturing lines. Our work presents a strategy that leverages rapidly advancing computational techniques to overcome the limitations of conventional hardware architectures in hyperspectral imaging. This compact and integrable solution is particularly well-suited for deployment in resource-constrained environments.

Asymmetric light propagation is crucial to the development of optical-based functional components in nanophotonics. Diverse configurations and structures have been proposed to allow asymmetrical propagation of photonic signal, but on-chip integration is difficult to achieve due to their complex structure and/or relatively large footprint. Here we report the first design and realization of asymmetric light propagation in single semiconductor nanowires with a composition gradient along the length. We show the asymmetric nanowire waveguides can be synthesized using a simple thermal evaporation and vapor transport approach without involving complicated and costly fabrication processes. Our studies demonstrate the asymmetric nanowire waveguides offer some significant advantages over previous designs, including ultra-low operation power, tunable working wavelength and nanoscale footprint, making them attractive building blocks for integrated photonic circuits.