Variable pulse repetition frequency output from an optically injected solid state laser

Abstract

An optically injected solid state laser (OISSL) system is known to generate complex nonlinear dynamics within the parameter space of varying the injection strength of the master laser and the frequency detuning between the master and slave lasers. Here we show that within these complex nonlinear dynamics, a system which can be operated as a source of laser pulses with a pulse repetition frequency (prf) that can be continuously varied by a single control, is embedded. Generation of pulse repetition frequencies ranging from 200 kHz up to 4 MHz is shown to be achievable for an optically injected Nd:YVO4 solid state laser system from analysis of prior experimental and simulation results. Generalizing this to other optically injected solid state laser systems, the upper bound on the repetition frequency is of order the relaxation oscillation frequency for the lasers. The system is discussed in the context of prf versatile laser systems more generally. Proposals are made for the next generation of OISSLs that will increase understanding of the variable pulse repetition frequency operation, and determine its practical limitations. Such variable prf laser systems; both low powered, and, higher powered systems achieved using one or more optical power amplifier stages; have many potential applications from interrogating resonance behaviors in microscale structures, through sensing and diagnostics, to laser processing.

Complexity in pulsed nonlinear laser systems interrogated by permutation entropy

“…3 for an optically injected solid state laser (OISSL) [14,17]. This data was recorded with the laser operating in a relatively stable region of the parameter space with normalized frequency detuning Δω = −1.849 and normalized injection strength K = 0.226.…”

“…Both of these systems, when operated with appropriate parameter settings, produce less complex dynamics than that seen in a semiconductor laser with optical feedback (SLWOF) system. The OISSL system, subject to variation of injection strength and frequency detuning of the injected light, produces spiky, pulse-like output power that can have a continuously variable dominant repetition frequency [17] and chaotic variation in spike amplitude [18], depending on the system parameters. The VCSEL system displays a similar spiky output [19,20], although not as clean as that seen in some regions of the OISSL operating parameter space.…”