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Development of a composite polymer-dye medium for tunable laser emission
摘要： We demonstrate optically pumped laser medium with emission in the visible spectral range from binary solutions of Rhodamine 6G and Rhodamine B in epoxy resin as matrix without appending additional scattering centers. A frequency doubled Q-switched Nd: YAG laser was used for pumping. The generation’s behavior is similar to random laser (RL) with no external optical resonator. The in?uence of the nanostructured morphology of the medium on the laser properties was investigated by means of SEM, AFM, TEM, SAED, Spectro?uorimetry and Spectrometry. The laser emission is characterized by high intensity – energy per pulse – 300 μJ, threshold pump energy 1.7 mJ, relatively low beam divergence of 70 mrad (for RL) and spectrally narrowed major peak at 597 nm. The new gain medium was also investigated in a conventional tunable resonator. Generation with continuous tuning in the spectral range 590–610 nm was obtained. This new e?ective nanostructured medium, which shows with high optical and energy parameters, can be used in speckle-free laser imaging, time-resolved microscopy, high speed optical converters and others photonics applications.
关键词： Dye laser,Tunable laser,Broadband laser,Random laser,Epoxy resin
更新于2025-09-23 15:19:57
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Dye-doped electrospun fibers for use as random laser generator: The influence of spot size and scatter concentration
摘要： The development of electrospun polymer fiber networks embedded with metal oxide nanoparticles in organic dye media favors the photons waveguiding and multiple scattering, providing the adequate environment for random laser action. The use of water-soluble polymer solution as support for electrospun matrix introduces relevant application in biomedical applications. Herein, it is explored the use of block copolymers (Eudragit L100) as support for electrospinning of polymer fiber doped with titanium dioxide (scatter centers) and rhodamine B (gain media). The resulting fiber net presented random laser behavior that depends on aggregation degree of gain media (rhodamine B) due to the combination of reabsorption/reemission processes with tunable response (emission peak position). These results open new possibilities for use of low-cost and water soluble electrospun-based random lasers based on organic dyes and random network of polymer matrix.
关键词： Fibers,Electrospinning,Organic dye,Random laser
更新于2025-09-23 15:19:57
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Replica Symmetry Breaking in a Weakly Scattering Optofluidic Random Laser
摘要： We report the observation of replica symmetry breaking (RSB) in a weakly scattering optofluidic random laser (ORL). Coherent random lasing is indicated by the presence of narrow peaks rising out of the spectral background. This coherence helps to identify a random laser threshold, which is expected to be gradual with weak scattering. We find that lasing action initiated using optical pulsed pumping coincides with the onset of both RSB and Lévy flight statistics. However, the transition from the photonic paramagnetic to photonic glass phase is more subtle in that the Parisi overlap function broadens instead of completely changing shape. This subtlety is balanced by an accompanying result of identical experimental conditions giving rise to lasing or no lasing depending on the shot. Additional statistical calculations and investigations into the fundamental physical mechanisms present in the ORL support this conclusion. Using simple numerical models, we study the critical spectral properties required for RSB to occur, as indicated by the Parisi overlap function. The simplicity of the models helps demonstrate the sensitive nature of this tool and the necessity of additional verification of the physical mechanisms present in the experiment.
关键词： replica symmetry breaking,Lévy flight statistics,Parisi overlap function,optofluidic random laser,mode competition
更新于2025-09-23 15:19:57
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Perovskite random lasers on fiber facet
摘要： Hybrid lead halide perovskites have made great strides in next-generation photovoltaic and optoelectronic devices. Random lasers based on perovskite materials have been intensively investigated, but the miniaturization of perovskite random lasers has not been achieved up to now. Here, we report the fabrication of perovskite random lasers based on perovskite films deposited on the optical fiber facets using a dip-coating method. Under optical pumping conditions, random lasing was observed with minimum threshold energy of 32.3 μJ/cm2 at ~550 nm; also, the lasing threshold decreased with increasing diameter of the optical fiber. The results show that the random lasing emission originates from the scattering between the perovskite crystal grains, and the decreased threshold is attributed to the increased active area of the perovskite film. The directionality of perovskite random lasers indicates that the divergence angle of the laser beam is less than 60°. We also demonstrate that the perovskite random laser on the fiber facet can prevent speckle formation and improve image quality. These results may promote the applications of random lasers in compact sources and integrated optoelectronic devices.
关键词： perovskite,optical fiber,random laser
更新于2025-09-23 15:19:57
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Excess Random Laser Action in Memories for Hybrid Optical/Electric Logic
摘要： To surmount the scalability limitations of the nano-electronics industry, the invention of resistance random access memory (RRAM) has drawn considerable attention in recent years for being a new-era memory. Nevertheless, the data transmission speed of RRAM is confined by virtue of its sequential reading nature. To improve upon this weakness, a hybrid optical/electric memory with ION/IOFF ratio up to 105 and laser-level optical signal is proposed. The device was engineered through an adroit design of integrating a random laser (RL) into the conducting bridge random access memory (CBRAM). According to the electrochemical metallization (ECM) effect of CBRAM, agglomerative silver nanoparticles form in the insulating layer during the ON/OFF switching process, which can serve as scattering centers. By adding CdSe/ZnS quantum dots (QDs) as gain medium, a random laser system is obtained. Due to the quantum confinement effect, the device also features spectral tunable signal feedback by modulating the size of the QDs. In this study, devices with two different sizes of QDs are demonstrated such that a multiple-bits AND gate logic can be achieved. The innovation behind this RL-ECM memory might facilitate a key step toward the development of ultrahigh speed information technology.
关键词： RRAM,AND gate logic,random laser,electrochemical metallization effect,CdSe/ZnS colloidal quantum dots
更新于2025-09-23 15:19:57
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Grain Boundary Induced Ultralow Threshold Random Laser in a Single GaTe Flake
摘要： Random lasing is a lasing phenomenon realized in random media, and has attracted a great deal of attention in recent years. An essential requirement for strong random lasing is to achieve strong and recurrent scattering among grain boundaries of a disordered structure. Herein, we report a random laser (RL) based on individual polycrystalline GaTe microflakes (MFs) with a lasing threshold of 4.15 kW cm-2, about 1-2 orders of magnitude lower than that of the reported single GaN microwire random laser. The strongly enhanced light scattering and trapping benefit from the reduced grain size in the polycrystalline GaTe MF, resulting in a ultralow threshold. We also investigate the dependence of spatially localized cavities’ dimension on the pumping intensity profile and temperature. The findings provide a feasible route to realize RL with low threshold and small size, opening up a new avenue in fulfilling many potential optoelectronic applications of RL.
关键词： fast Fourier-transform,random laser,GaTe,ultralow-threshold,grain-boundary
更新于2025-09-23 15:19:57
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Tunable Low Power Piezo-Plasmonic Random Laser under External Voltage
摘要： This study was aimed to introduce a new kind of low power and tunable random lasers based on piezo-plasmonic core/shell nanoparticles (NPs) consisting of lead zirconate titanate and gold, mixed by different concentrations of Rhodamine B (RhB) dye. To get the random lasing, the sample was exposed to pulsed laser at the presence and in the absence of an external voltage. We got a gradual increase in the thermo-plasmonic emission intensity was enhanced by decreasing the threshold lasing due to an increase in scattering, which more easily made a close loop path in the gain medium. Our results showed some spikes with the same pump energy in emission spectrum which confirmed the coherence random lasing. This phenomenon could be observed in PZT@Au NPs and it could not be observed in Au@PZT NPs in low and high concentrations. properties by increasing the applied voltage on core/shell NPs, which depended on the boundary conditions between the shell and the core samples. By external voltage, the Furthermore, in lower pump energy, we observed low peak intensity in the emission spectrum and it increased as the pump energy overrode the lasing threshold. The emission spectrum became narrow with a sharp increase in the emission intensity, which we could reach a rapid decrease in the full width at half maximum (FWHM) of the emission intensity above the threshold. These results showed the possibility of using these new kinds of materials for low threshold and controllable random lasing.
关键词： external voltage,thermo-plasmonic,piezo-plamsonic,random laser,Au@PZT,PZT@Au core/shell NPs
更新于2025-09-19 17:13:59
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Fabrication of mechanical controllable, sticky and flexible random lasers based on double-sided tapes
摘要： In this paper, we report on the fabrication of mechanical controllable, sticky and ?exible random lasers based on double-sided tapes that are cheap and commonly available. A double-sided tape is used as the scattering medium. Two di?erent solutions of rhodamine B dye doped with ethylene glycol and SU-8 epoxy based polymer are applied as the gain medium. By investigation of the random laser operating lifetimes for both samples, it is shown that SU-8 epoxy based polymer is the preferred host for dye in practical utilizations. Furthermore, we observe that for the sample fabricated based on the polymeric solution of RhB dye doped SU-8 resin, bending the sample leads to an increase of lasing threshold by 39 MW/cm2. This study can pave the way for manufacturing low cost, simply utilized and mechanical controllable random lasers which can also sticks to di?erent surfaces as the marker.
关键词： Multiple light scattering,SU-8 epoxy based polymer,Random laser,Flexible devices,Double-sided tapes
更新于2025-09-19 17:13:59
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Resonant energy transfer and light scattering enhancement of plasmonic random lasers embedded with silver nanoplates
摘要： The resonant energy transfer enhancement from a plasmonic random laser (PRL) has been investigated by means of a dye-covered PVA film with embedded silver nanoplates (DC-PVA/AgNPs). Different sizes and morphologies of AgNPs were adopted to shift the localized surface plasmon resonance (LSPR) and intensify recurrent light scattering between the AgNPs. For better overlap between surface plasmon resonance and the photoluminescence of fluorescent molecules with appropriately-sized silver nanoprisms, the slope efficiency of the PRL was greatly enhanced and the lasing threshold was obviously reduced. In addition, the photon lifetime for the DC-PVA/AgNPs film reveals an apparent decline around 1.39 ns owing to better coupling with LSPR. The stronger light scattering of samples with bigger-sized silver nanoprisms has been demonstrated by coherent back scattering measurements, which reveals a smaller transport mean free path around 3.3 mm. With a-stable analysis, it has been successfully demonstrated that the tail exponent a can be regarded as an identifier of the threshold of random lasing.
关键词： localized surface plasmon resonance,resonant energy transfer,silver nanoplates,light scattering enhancement,plasmonic random laser
更新于2025-09-19 17:13:59
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Properties of Random Lasers in a hollow core photonic crystal fiber
摘要： We investigate the properties of random lasers based on light guiding and scattering in a hollow core photonic crystal fiber. We develop air-filled and filled cladding for different fiber core diameters of photonic crystal fibers. The fiber cores are filled with various concentrations of alumina nanoparticles (~50 nm) and Rhodamine 6G in ethylene glycol solution. The effects of light guiding and scattering were studied in terms of filled and air-filled cladding, different fiber core diameters and scattering regimes. Fiber with air-filled cladding provides guiding to the sample leading to random lasing, whereas the sample without scattering does not produce any narrow emission spectra. Less scattering is needed for random lasers in a fiber because too much scattering may hinder guiding in the fiber core leading to high lasing threshold. Both guiding and scattering are needed in random lasers in a fiber as the absence of one of these light phenomena results in broad emission spectra with no lasing threshold. The experimental results are supported with the numerical modeling. We observe that random lasers perform better in the weakly scattering regime than the diffusive regime, which is well predicted by the modeling.
关键词： random laser in a fiber,scattering and guiding
更新于2025-09-19 17:13:59