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- 实验方案
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Self-Sufficient and Highly Efficient Gold Sandwich Upconversion Nanocomposite Lasers for Stretchable and Bio-applications
摘要： Multi-functional lanthanides doped upconversion nanoparticles (UCNP) have spread its wings in the fields of flexible optoelectronics and biomedical applications. One of the ongoing challenges lies in achieving UCNP based nanocomposites which enable continuous wave (CW) laser action at ultralow-threshold. Here, gold sandwich UCNP nanocomposites {gold (Au1)-UCNP-gold (Au2)} capable of exhibiting lasing at ultralow-thresholds under CW excitation is demonstrated. The metastable energy-level characteristics of lanthanides is advantageous for creating population inversion. In particular, localised surface plasmon resonance based electromagnetic hotspots in the nanocomposites and the giant enhancement of scattering coefficient for the formation of coherent closed loops due to multiple scattering facilitates the process of stimulated emissions as confirmed by theoretical simulation. The nanocomposites are subjected to stretchable systems for enhancing lasing action (threshold ~0.06 kW/cm2) via light trapping effect. The applications on bioimaging of HeLa cells and antibacterial activity (photothermal therapy) are demonstrated using the newly designed Au1-UCNP-Au2 nanocomposites.
关键词： stretchable lasers,electromagnetic hotspots,random lasing,upconversion laser,solution-processed,continuous-wave laser
更新于2025-09-19 17:13:59
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Electrically Tunable Liquid-Crystala??Polymer Composite Laser with Symmetric Sandwich Structure
摘要： This study investigates and develops for the first time an electrically tunable liquid-crystal?polymer composite laser with a symmetric sandwich structure. This structure includes two identical polymer-stablized cholesteric liquid-crystal (PSCLC) layers, and a dye-doped nematic LC (DDNLC) layer is sandwiched between them. The PSCLC and DDNLC layers act as distributed Bragg reflectors and half-wave plate with a gain medium, respectively. The entire cell behaves as an optical cavity, where the resonant modes occur at the maxima of the cell’s transmission spectrum. Through the competition among the resonant modes by considering the gain and loss, the resonant mode with the lowest lasing threshold can be sieved out for lasing occurrence. When the same voltage is applied to the two PSCLC layers, the pitch gradients are simultaneously formed through the two layers because of the electrically induced ion-concentration gradients. When the voltage increases, the pitch gradients increase, thereby leading to the expansion of the cell photonic band gap (PBG) and blue shift of the lasing wavelength. The sandwich cell PBG can expand from 55 nm to over 170 nm, and the tuning range of the lasing wavelength is as high as 70 nm, which is the widest ever achieved in LC-related sandwich systems. The proposed configuration of the sandwich sample presents new insights into tunable LC PBG and laser devices, thereby providing potential applications in the form of sensors, medical imaging, displays and lighting, among others.
关键词： distributed Bragg reflectors,electrically tunable,dye-doped nematic LC,photonic band gap,liquid-crystal?polymer composite laser,optical cavity,symmetric sandwich structure,half-wave plate,lasing wavelength,polymer-stablized cholesteric liquid-crystal
更新于2025-09-19 17:13:59
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Fluorescence and Time-Delayed Lasing during Single Laser Pulse Excitation of a Pendant mm-Sized Dye Droplet
摘要： Fluorescence and lasing emission that are produced separately in time during excitation laser pulse for an mm-sized Rhodamine 6G dye-water droplet are reported. The droplet acts as a quasi-spherical closed optical resonator and due to multiple internal reflections, the resonant amplified emission is delayed with respect to fluorescence emission. Measurements of the temporal evolution of the droplet’s emission were performed by varying the signal acquisition gate width and gate delay with respect to the pumping pulse. The droplet emission spectra are structured in two bands which appear one after the other in time: first, the fluorescence emission band which follows pumping laser pulse time shape and then a second band, the lasing band, placed at shorter wavelengths and formed in time after the peak of the pumping laser pulse intensity, on the pulse tail. The lasing threshold pumping intensity is much lower than those for typical dye lasers.
关键词： optical signal sampling,laser dye,mm-sized droplets,lasing,laser-induced fluorescence
更新于2025-09-16 10:30:52
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Multimode lasing in wave-chaotic semiconductor microlasers
摘要： We investigate experimentally and theoretically the lasing behavior of dielectric microcavity lasers with chaotic ray dynamics. Experiments show multimode lasing for both D-shaped and stadium-shaped wave-chaotic cavities. Theoretical calculations also find multimode lasing for different shapes, sizes, and refractive indices. While there are quantitative differences between the theoretical lasing spectra of the stadium and D-cavity, due to the presence of scarred modes with anomalously high-quality factors, these differences decrease as the system size increases, and are also substantially reduced when the effects of surface roughness are taken into account. Lasing spectra calculations are based on steady-state ab initio laser theory, and indicate that gain competition is not sufficient to result in single-mode lasing in these systems.
关键词： multimode lasing,stadium-shaped cavities,D-shaped cavities,gain competition,wave-chaotic semiconductor microlasers,scarred modes,surface roughness
更新于2025-09-16 10:30:52
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On-chip single-mode optofluidic microresonator dye laser sensor
摘要： Optofluidic dye laser devices have great potential as coherent light sources for lab-on-a-chip applications such as sensing and spectroscopy applications, owing to their promising properties as wide wavelength-tunability, proper microfluidic integration, and an extremely miniaturized footprint. The wide emission spectrum of dye molecules and narrow free spectral range of ring resonators, make these lasers inherently multi-mode. In this article, two polydimethylsiloxane-based miniaturized optofluidic ring resonator dye lasers are numerically designed and investigated. First, multi-mode lasing from a single optofluidic ring resonator with a spectral linewidth of 10 nm and a threshold energy density of 2.2 μj/mm2 is demonstrated. Then, by exploiting two coupled optofluidic ring resonators and Vernier effect, single-mode lasing at a center wavelength of 566 nm with a spectral linewidth as small as 5.36×10-4 nm is achieved. Moreover, simulations demonstrate the sensitivity of 500 nm/RIU for the proposed dye laser sensor.
关键词： Optofluidic,Single-mode lasing,Dye laser sensor,Ring resonator
更新于2025-09-16 10:30:52
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Economical generation regime of a supersonic continuous-wave chemical DF laser
摘要： We have performed experimental and computer-aided theoretical studies of the effect of the dilution degree y2 of a secondary fuel (deuterium) by an inert gas (helium) on the output characteristics of a supersonic cw chemical DF laser with a flat nozzle array, constructed in accordance with the nozzle – nozzle reagent mixing scheme. It is shown that an increase in the dilution degree in the range of 0 ￡ y2 ￡ 20 leads to a monotonous increase in the lasing zone length (a decrease in the radiation load on the resonator mirrors) and a drop in the laser specific energy output. With an increase in the optical path length (a decrease in the threshold gain), the sensitivity of the laser energy characteristics to the dilution degree decreases. Consequently, for a high-power DF laser (with a long nozzle array) with partial replacement of expensive deuterium with cheaper helium, a potential possibility for the implementation of an economical generation regime with acceptable specific energy output is achieved. The conditions for the implementation of this regime are identified.
关键词： economical generation regime,supersonic cw chemical DF laser,secondary fuel,inert diluent,energy characteristics,dilution degree,lasing zone length
更新于2025-09-16 10:30:52
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High-coupling distributed feedback lasers for the 1.55 μm spectral region
摘要： A technique for the development of high-coupling distributed-feedback (DFB) lasers for the 1.55 mm spectral region is described. The lasers demonstrate stable single-frequency generation in a broad temperature range with a maximum side-mode suppression ratio of more than 30 dB.
关键词： single-frequency lasing,distributed feedback,semiconductor laser,side-mode suppression ratio
更新于2025-09-16 10:30:52
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Regulating the Single-Mode Lasing Intensity of Semiconductor Lasers without Wavelength Shift
摘要： A simple method to regulate the single-mode lasing intensity of semiconductor lasers without wavelength shift is demonstrated in this paper. The basic component is a digital micro-mirror device (DMD), which can be taken as an adjustable two-dimensional grating by its special structure. The lasing peak wavelength and peak intensity are respectively regulated by the DMD angular position and the DMD setting. The lasing peak wavelength could be tuned over by rotating the DMD. Meanwhile, the lasing peak intensity could be regulated by the DMD setting, which generates optical feedback digitally. The regulating speed is very high (up to 10kHz) and has no wavelength shift in the lasing mode, which is more stable and faster than the conventional method.
关键词： optical feedback,Semiconductor lasers,lasing mode regulation
更新于2025-09-16 10:30:52
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Transition Between Exciton-Polariton and Coherent Photonic Lasing in All-Inorganic Perovskite Microcuboid
摘要： All-inorganic lead halide perovskites are ideal platforms to investigate the fundamental physics of the light-matter interactions, due to their strong oscillator strength at room temperature and various microstructures. In this paper, we investigated strong exciton-photon coupling and coherent photonic lasing in a same high-quality self-assembled CsPbBr3 perovskite microcuboid grown by a chemical vapor deposition method. The vacuum Rabi splitting of polariton up to 309 meV, and the exciton-like and photon-like components in low polariton states at different cavity-exciton detuning, were revealed by angle-resolved photoluminescence spectra at room temperature. Moreover, we realized a coherent photonic lasing with a high quality-factor (4153) and narrow linewidth (0.13 nm) in the microcuboid above threshold (16 μJ/cm2), originated from population inversion. Significantly, the interference pattern of the coherent lasing through the Young's double-slit interference method based on far-field Fourier optical system, directly indicate the parity (odd) of the lasing mode and the asymmetric electric-field distribution in the CsPbBr3 microstructure. Our work demonstrates for the first time a transition from the strong coupling regime (vertical Fabry–Pérot oscillation) to weak coupling regime (lateral Fabry–Pérot oscillation) in such self-assembled microcuboid under the competition between gain and internal loss. Based on this mechanism, a considerable promise is expected to enrich the functions of micro-nano structure photoelectric devices by precisely controlling the quality-factor and gain of such microstructure.
关键词： Exciton-polaritons,Young's interference,Perovskite microcuboid,Photonic lasing,Fabry–Pérot microcavity
更新于2025-09-16 10:30:52
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Manipulating Light–Matter Interactions in Plasmonic Nanoparticle Lattices
摘要： Rationally assembled nanostructures exhibit distinct physical and chemical properties beyond their individual units. Developments in nanofabrication techniques have enabled the patterning of a wide range of nanomaterial designs over macroscale (>in.2) areas. Periodic metal nanostructures show long-range diffractive interactions when the lattice spacing is close to the wavelength of the incident light. The collective coupling between metal nanoparticles in a lattice introduces sharp and intense plasmonic surface lattice resonances, in contrast to the broad localized resonances from single nanoparticles. Plasmonic nanoparticle lattices exhibit strongly enhanced optical fields within the subwavelength vicinity of the nanoparticle unit cells that are 2 orders of magnitude higher than that of individual units. These intense electromagnetic fields can manipulate nanoscale processes such as photocatalysis, optical spectroscopy, nonlinear optics, and light harvesting. This Account focuses on advances in exciton?plasmon coupling and light?matter interactions with plasmonic nanoparticle lattices. First, we introduce the fundamentals of ultrasharp surface lattice resonances; these resonances arise from the coupling of the localized surface plasmons of a nanoparticle to the diffraction mode from the lattice. Second, we discuss how integrating dye molecules with plasmonic nanoparticle lattices can result in an architecture for nanoscale lasing at room temperature. The lasing emission wavelength can be tuned in real time by adjusting the refractive index environment or varying the lattice spacing. Third, we describe how manipulating either the shape of the unit cell or the lattice geometry can control the lasing emission properties. Low-symmetry plasmonic nanoparticle lasing responses, and multiscale plasmonic superlattices—finite patches of lattices can show polarization-dependent nanoparticles grouped into microscale arrays—can support multiple plasmon resonances for controlled multimodal nanolasing. Fourth, we discuss how the assembly of photoactive emitters on the nanocavity arrays behaves as a hybrid materials system with enhanced exciton?plasmon coupling. Positioning metal?organic framework materials around nanoparticles produces mixed photon modes with strongly enhanced photoluminescence at wavelengths determined by the lattice. Deterministic coupling of quantum emitters in two-dimensional materials to plasmonic lattices leads to preserved single-photon emission and reduced decay lifetimes. Finally, we highlight emerging applications of nanoparticle lattices from compact, fully reconfigurable imaging devices to solid-state emitter structures. Plasmonic nanoparticle lattices are a versatile, scalable platform for tunable flat optics, nontrivial topological photonics, and modified chemical reactivities.
关键词： nanoscale lasing,surface lattice resonances,exciton?plasmon coupling,light?matter interactions,plasmonic nanoparticle lattices
更新于2025-09-16 10:30:52