Numerical investigation of properties of picosecond pulses in InGaN lasers under Q-switching operation

Abstract

This paper presents a theoretical investigation of picosecond pulse generation in blue-violet InGaN semiconductor lasers with an additional saturable absorber (SA) under a Q-switching mechanism. This study addresses the increasing demand for compact, high-performance pulsed sources in fields such as medical diagnostics, imaging, dermatology, and laser-assisted surgery, etc. We describe the laser structure. Special attention is given to this new laser configuration that is proposed in this paper. The difference to previous structures is that in our case the SA is located in the outer regions of laser and can be controlled by a small injected current. We mention that such devices could be realized experimentally. The theoretical framework is based on rate equation model. We begin our analysis with the principles of pulse generation. We perform numerical simulations to analyze the main pulse characteristics, such as peak power, pulse energy, and full width at half maximum (FWHM), as a function of various structural and material parameters, such as SA length, losses in the full device, and back facet reflectivity. These results provide valuable guidance for optimizing the design and operation of InGaN-based Q-switched laser sources for different applications.