Coherent Random Lasing from Dye Aggregates in Polydimethylsiloxane Thin Films

Abstract

The coherent random laser (CRL) from dye-doped polydimethylsiloxane (PDMS) has been investigated in both nanoparticle-doped (NP-doped) thin films and pure dye thin films. Compared with the literature, the pump threshold is only 1.5 mJ/cm in the pure dye thin film with a low dye concentration. The spontaneously formed micro-/nanocrystals of Pyrromethene 597 (PM597) dye support both gain and random feedback in the bulk of the PDMS during the sample preparation. When the SiO NPs were doped, the pump threshold was reduced to 0.75 mJ/cm. The threshold increased after the film was peeled off from glass, which indicates that the photon localization effect of the leaky-waveguide structure plays an important role in the reduction of the CRL threshold. By a change in the pump stripe length or the thickness of the film, the peak wavelength red-shifts 6.7 or 5.93 nm, respectively. The PM597 dye molecule solubility changes, and they spontaneously aggregate in the process of toluene volatilization; the PDMS cures, which is the reason for the formation of PM597 micro-/nanocrystals. This thin film random laser with a low dye concentration can be used in integrated optoelectronics and display imaging.

A ring-shaped random laser in momentum space

“…When the random lasers are vertically pumped by the pulses with a power density of 0.2188 MW cm -2 , the random lasing intensity increases with d rising from 1.2 to 24 μm, following a red-shift behavior of the center wavelength as large as about 10 nm. Larger thickness of the film can provide larger gain for random lasing and a longer period in the gain region which leads to a strong reabsorption of dye molecules and then the spectral red-shift of random lasing 38,42 . The wavelength shift phenomenon supply an optional approach to regulate the emission wavelength of random laser by controlling the thickness d of the coated polymer.…”

Natural Born Laser Dyes: Excited-State Intramolecular Proton Transfer (ESIPT) Emitters and Their Use in Random Lasing Studies

“…All of these systems strive to lower the lasing threshold, which is directly related to the luminescent properties of a given material. Light self-absorption can be very detrimental for efficient RL which makes ESIPT dyes with their intrinsic large Stokes shift very attractive compared to previously reported RL materials [38,39,40].…”

Pump-Controlled Plasmonic Random Lasers from Dye-Doped Nematic Liquid Crystals with TiN Nanoparticles in Non-Oriented Cells

“…However, when the pump energy density exceeds 0.2 mJ/cm 2 , the FWHM of the emission spectrum narrows sharply to about 0.3 nm. Therefore, we obtain that the pump threshold, defined by the sharp narrowing of the emission spectrum and the slope changing of the peak intensity as the pump energy density increases, is about 0.2 mJ/cm 2 , which is much lower than that in the references [10,[34][35][36].…”