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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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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Plasmonic Random Laser with the Embedding of Silver Nanostructure Materials
摘要： In contrast to conventional lasers, random lasers (RLs), without cavity mirrors, were generated based on recurrent light scattering within nano-materials and possessed peculiar properties for practical applications. To date, researchers are not only interested in the novel nano-materials for the generation of RL but also curious in the manipulated property of RL through temperature and electric filed [1]. In addition, plasmonic random laser (PRL)[2] based on the localized surface plasmon resonance (LSPR) of metallic nanoparticles has attracted great interest. In this work, the dye-covered PVA (DC-PVA) film with the embedding of silver nano-particles (AgNPs) was produced to investigate the enhancement of emission spike intensity from PRL and the underlying mechanism by varying the size and shape of AgNPs. Here, the AgNPs were synthesized by a soft solution-phase approach inside the DI water [3]. Depending on the size and shape of AgNPs in colloidal solution, the absorbance spectrum in Fig. 1(a) reveals different peak absorption wavelength (λp) at 404 nm and 610 nm, respectively, and shows deep yellow and navy color (Fig. 1(a)). The PVA film with embedding of AgNPs (PVA/AgNPs) was produced by dropping the mixed solution, comprising PVA powder and AgNPs, onto a glass substrate. After drying, the laser dye (Pyrromethene 597, Exciton inc.) was coated on the top of PVA film (Inset of Fig. 1: the structure of sample). In this work, the coherent back scattering measurement (CBS) measurement [4] was performed to obtain the transport mean free path (lp) of pure DC-PVA film (green squares: Sample-I) and DC-PVA/AgNP film [red triangles: Sample-II (λp at 405 nm), blue circle: Sample-III (λp around 610 nm)]. The solid lines represent the theoretical fitting curves to obtain the lp of three samples around 10.3, 8.7 and 3.6 μm. The value of lp decreases obviously after AgNPs was embedding in the PVA film to illustrate the enhancement of light scattering. In order to generate RL, we excited all the produced samples by a frequency doubling Q-switched Nd:YAG laser with a central wavelength of 532 nm. The 10 Hz pump pulses were focused onto the sample with a long line stripe by a cylindrical lens with focal length f = 7cm. The side emission of the sample was collected by the fiber tip and measured by the spectrometer (resolution about 0.3 nm, Ocean Optics Inc.). Inset of Fig. 1(b) shows the emission spectra of DC-PVA film without (Sample-I, green solid curve) and with (Sample-II: red solid curve and Sample-III: blue solid curve) AgNPs. Even at relatively high pulse energy, the Sample-I (without AgNPs) only reveals broad spontaneous emission spectrum with the maximum intensity at λ = 578 nm. For the sample-II and sample-III (DC-PVA/AgNP film), the discrete emission spikes at around about λ=576 and 583 nm on the top of broad spontaneous emission can be revealed which is the characteristic of RL. In order to qualitatively distinguish the operation state of RL, the α-stable distribution [5] proposed by Uppu et al. was used to analysis the intensity fluctuation (red) of the sample by sampling 1000 spectrum slots. The intensity distribution (red histogram) can be theoretical fitting by the equation (blue solid curves in Figs. 1(c) and 1(d)) to obtain the α=1.99 and 1.58, respectively, which reveals the Gaussian and Levy distribution.
关键词： random lasers,light scattering,localized surface plasmon resonance,plasmonic random laser,silver nano-particles
更新于2025-09-12 10:27:22