Temporal profiles for measuring threshold of random lasers pumped by ns pulses

Threshold behavior and tunability of a diffusive random laser

In this study, it is shown that the dynamics of the lasing threshold and the intensity saturation of a diffusive random laser can be visualized by one spectral feature: the peak wavelength shift (tunability). The varied ink concentration and pump energy were utilized to experimentally induce the peak shift and the lasing threshold dynamics. It was found that the peak wavelength progressively turns from blueshift to redshift upon crossing the lasing threshold. A unique random laser threshold regime instead of a threshold point is revealed. This threshold regime was also compared with those deduced from the replica symmetry breaking and the Lévy statistics, both are the state-of-the-art methods to predict the behavior of a complex system. All three results show the high agreement in terms of unveiling the lasing nature of the random lasers.

1337 nm Emission of a Nd3+-Doped TZA Glass Random Laser

Random lasers have been studied using many materials, but only a couple have used glass matrices. Here, we present a study of zinc tellurite and aluminum oxide doped with different percentages of neodymium oxide (4 wt.%, 8 wt.%, and 16 wt.%) and demonstrate for the first time random laser action at 1337 nm. Laser emission was verified and the laser pulse's rise time and input-output power slope were obtained. A cavity composed of the sample's pump surface and an effective mirror formed by a second, parallel layer at the gain-loss boundary was probably the main lasing mechanism of this random laser system. The reason for the absence of emission at 1064 nm is thought to be a measured temperature rise in the samples' active volume.

Properties and Applications of Random Lasers as Emerging Light Sources and Optical Sensors: A Review

In a random laser (RL), optical feedback arises from multiple scattering instead of conventional mirrors. RLs generate a laser-like emission, and meanwhile take advantage of a simpler and more flexible laser configuration. The applicability of RLs as light sources and optical sensors has been proved. These applications have been extended to the biological field, with tissues as natural scattering materials. Herein, the current state of the RL properties and applications was reviewed.