Incoherent random lasing action in dye solution with dielectric nanoparticles

Jian Xuan Liu¹, Tsung Sheng Kao^1*

¹Department of Photonics, National Yang Ming Chiao Tung University, Hsinchu City, Taiwan

* Presenter:Tsung Sheng Kao, email:tskao@nycu.edu.tw

Incoherent random lasing action results from the optical non-resonant intensity feedback, which is based on photon diffusion in the gain medium. The bandwidth of the emission spectrum may be dramatically reduced to a few nanometers at the pumping level of energy density beyond the lasing threshold. Besides, the spatial energy distribution is extended over the system since the photons are in a diffusive manner. The random lasing behavior can take place in many materials, for example, microcrystalline perovskites, biological tissues, laser dye-doped with nanoparticles, semiconductor powder, etc. In this paper, we investigate the spectral characteristics of random lasing behaviors via the Monte Carlo calculation in dye solution with random distributed TiO₂ dielectric nanoparticles. The calculation model not only shows the correspondence to the experimental measurements but also suggests that lasing threshold is highly dependent on the pumping spot size and scattering mean-free path in a disordered medium. Furthermore, we simulate the effect of single-particle Mie resonance on emission spectrum, investigating the tunability capability of lasing wavelengths via different random configurations in the gain media.

Keywords: random laser, photon diffusion,, Mie scattering, Monte Carlo simulation, , laser dye