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By using chaotic vertical-cavity surface-emitting lasers as entropy sources for key generation, a security system based on physical unclonable functions can be created that offers response rates above 500 Gbps with an energy consumption below 1 pJ per bit per laser emitter.

Researchers realize watt-class frequency modulation using compact coherent optical transmitters based on frequency-modulated photonic-crystal surface-emitting lasers. The system has implications for long-distance free-space optical communications.

A monolithic mode-locked semiconductor laser with a continuously and widely tunable repetition rate is achieved by using a microwave driving signal that induces a spatiotemporal gain modulation along the entire laser cavity.

An on-chip tunable laser operates by harnessing nanomechanical resonances at the radio frequency, achieving ultralow tuning power consumption.

A nearly flat broadband quantum walk comb laser is demonstrated in the near-infrared region. A bandwidth of 1.8 THz with a wallplug efficiency of 6% and an ultra-narrow radio frequency linewidth of 1 Hz is achieved at the fundamental repetition rate of 1 GHz.

Photons carrying orbital angular momentum inherit chirality from their twisted wavefront. Here, authors propose a twisted bilayer photonic structure - consisting of semiconductor membrane metasurfaces - where helical wavefronts are combined with non-Hermitian coupling, yielding orbital chiral lasing at telecom wavelengths.

Organic thin-film lasers offer compact, low-cost light sources for applications like sensing and optical memory. Here, authors fabricated sub-wavelength gratings using a femtosecond laser, providing high flexibility. These gratings serve as feedback structures for an optically pumped organic laser.

THz integrate light sources represent an important building blocks for various applications. Here the authors report an electrically driven topological laser based on photonic Majorana zero mode that can convert electricity directly into THz single-mode laser with topologically nontrivial beams.

Topological lasers often suffer from low directionality, and/or complex design requirements hindering operation at small wavelengths. Here, by using a few monolayers of perovskite quantum dots, the authors demonstrate a lithography-free, vertical-emitting, single-mode laser emitting in the green.

Generation and control of short pulse is desired for ultrafast applications. Here the authors demonstrate ultrafast pulse generation using self-evolving photonic crystal that can transition from high loss to low loss state based on dynamic dispersion compensation.

The authors report the experimental demonstration of quadrupole higher-order topological nanolasers with the defect evolution strategy, supporting the lasing behavior of corner state single-mode emission at room temperature.

The researchers use gigahertz acoustic waves to control the gain and loss of confined modes of an exciton–polariton condensate in a microcavity, enabling dynamic population transfer. Selective transfer to the ground state yields single-level emission consisting of a spectral frequency comb with gigahertz repetition rates.

Optical metrology applications require lasers with high spectral purity but on-chip devices with sub-100 Hz linewidth are yet to be realized. Here, Liang et al.present a heterogeneously integrated, chip-scale semiconductor laser with 30 Hz integral linewidth and sub-Hz instantaneous linewidth.

The breaking of parity-time symmetric gain and loss profiles can be used to achieve single-mode lasing in coupled microring resonators. Here, Liuet al. show that this effect can be electrically controlled with a tunable lasing wavelength and strong sidemode suppression.

Integrated plasmonic sources are crucial in the development of plasmonic circuitry. Here, McPolin et al. show that vertical-cavity surface-emitting lasers can be employed as an on-chip, electrically pumped source or detector of plasmonic signals and also demonstrate waveguiding and frequency conversion on this platform.

The intrinsic Kerr nonlinearity in ring resonators is exploited to demonstrate passive isolation of a continuous-wave laser. Up to 35-dB isolation with 5-dB insertion loss was achieved on-chip.

Researchers present silicon photonic circuit that, with an integrated distributed-feedback (DFB) laser, enhances the DFB’s immunity to continuous-wave and modulated parasitic reflections from multiple reflections. The isolator-free operation of the integrated laser in a high-speed optical link was demonstrated, highlighting potential for data communication applications.

Low threshold lasing is widely required, especially for portable systems. Here the authors design a circular subwavelength metallic aperture in a QCL to shape its phase front and control diffraction losses, which in turn allows a lower threshold dissipation power, enabling the fabrication of shorter cavities.

Based on optically breaking time-reversal symmetry by spin polarizing a gain medium with a circularly polarized optical pump, an integrated scheme for controlling the chirality of orbital angular momentum lasing is demonstrated.

Producing pulses in the mid-IR often requires bulky sources and has been inaccessible with compact and versatile quantum cascade lasers (QCLs). Here, the authors demonstrate actively mode-locked, mid-IR QCL operation at room temperature.

Terahertz frequency combs are highly desired for applications in precision measurements, sensing, spectroscopy and metrology. Here the authors demonstrate the room-temperature chip-based THz frequency comb using nonlinear frequency generation from a mid-infrared quantum cascade laser comb.

Proper design of the gratings can enhance the efficiency of distributed-feedback and quantum cascade lasers. Here, Jin et al. use a hybrid grating system that superposes second- and fourth-order Bragg gratings and achieve high radiative efficiency and a single-lobe radiation pattern.

Fe₃O₄ nanoparticles deposited on top of GaN nanorods produce a spin-up and spin-down imbalance that makes the semiconductor emit coherent spin-polarized light.

Topological effects, first observed in condensed matter physics, are now also studied in optical systems, extending the scope to active topological devices. Here, Zhao et al. combine topological physics with non-Hermitian photonics, demonstrating a topological microlaser on a silicon platform.

Topologically protected lasing is reported in a lattice of polariton micropillars.

Highly strained germanium on silicon samples with up to 3.1% uniaxial strain are fabricated and then investigated by Raman spectroscopy. During optical pumping, changes in both the emission wavelength and output power are observed, indicating that bandgap modification and optical gain are occurring.

Theoretical analysis reveals that spasers do not differ fundamentally from conventional semiconductor lasers; differences are mainly technical and result from loss in the metal. Spasers are shown to have significantly inferior threshold currents and linewidths to those of vertical-cavity surface-emitting lasers, but their speed can be slightly greater.

A silicon nanobeam cavity laser integrated with monolayer molybdenum ditelluride enables room-temperature lasing in the near infrared.

A cavity that can switch between lasing and anti-lasing could inspire a new design of optical modulator.

Researchers demonstrate a watt-class high-power, single-mode photonic-crystal laser operating continuously at room temperature. A beam quality of M² ≤ 1.1 is achieved.

Orbital-angular-momentum (OAM) beams have great potential for multiplexing signals in optical communication, but creating a compact source is challenging. The authors integrate a chip-scale optical vortex emitter and DFB laser into a single monolithic device for direct electrically pumped production of OAM beams.

The authors demonstrate electrically pumped continuous-wave operation of a SiGeSn/GeSn lasers. The devices are based on a multi-quantum-well design in a small footprint micro-disk cavity resulting in driving parameters compatible with on-chip operation.

Solution-processable CdS ‘bulk’ nanocrystals show efficient on-chip lasing under quasi-continuous-wave conditions with excellent beam quality and pump thresholds.

The authors demonstrate mode-multiplexed holography using current-addressed OAM components in VCSELs to increase channel capacity. Monolithic nanoprinted holograms within 100×100 μm^2 footprint enable dynamic displays with a refresh rate of ~1.93 GHz.

Bose–Einstein condensation of photons is demonstrated in a large-aperture electrically driven InGaAs vertical-cavity surface-emitting laser diode at room temperature. The observed photon Bose–Einstein condensate exhibits the fundamental transversal optical mode at a critical phase-space density.

A completely solid-state, single-chip, microwave-frequency surface acoustic wave phonon laser can generate coherent phonons from thermal noise or resonantly amplify injected phonons using only a direct current bias field.

Colloidal quantum wells are highly promising for applications of solution-processed lasers, but their performance is limited by multi-excitonic nature of the materials. Here, the authors demonstrate optical gain in graded alloy core/shell CdSe/CdS@CdZnS quantum wells at less than one exciton per particle resulting in ultralow thresholds.

He et al. report a lanthanide-doping strategy for dual-halogen-alloyed perovskite microplates, which promotes phase segregation and facilitates ion migration in the alloyed case, while suppressing it in the phase-segregated state, resulting in dual-wavelength lasing in visible spectral region.

Fabricating semiconductor photonic lasers based on III-V materials are challenging because of the material mismatch with silicon. Here the authors monolithically grow quantum-dot-based photonic crystal membrane lasers directly on an on-axis silicon substrate.

Single-shot ranging enabled by single-photon detection allows dense point clouds to be acquired with greatly reduced laser pulse energy, while enhancing geometrical fidelity through the improved temporal resolution of devices in an ultralight LiDAR.

Researchers demonstrate quantum dot lasing using excitation by an electrically modulated (0.1–1% duty cycle), low-power continuous-wave laser diode, achieving lasing at a pump intensity just above 500 W cm⁻² at 77 K and 3.6 kW cm⁻² at room temperature.

Scientists demonstrate an optically pumped InP-based distributed feedback laser array monolithically grown on (001)-silicon operating at room temperature that is suitable for wavelength-division multiplexing applications.

Integrating UV lasers is of interest for portable optical clocks and ion-based quantum computers, but material absorption has impeded progress. Here, authors demonstrate a violet integrated laser using UV-transparent materials with mW-level output, narrow linewidth and precise frequency control.

The fabrication of a blue–violet semiconductor laser on a silicon substrate enhances the integration of optoelectronics with electronics.

Chiral emission from collective guided modes is demonstrated within a photonic crystal slab, showing an example of collective oscillations in the momentum space.