Experimental studies of high power diode lasers under high current short pulses for optoacoustics biomedical imaging

Abstract

High Power Diode Laser (HPDLs) can potentially be more suitable laser sources for commercial implementation of short pulse application such as optoacoustic biomedical imaging, compared to the commonly used solid state lasers due to their lower cost, compact size and higher repetition rate. However, the commercially available HPDLs are designed and characterized to operate with much longer pulse durations and lower peak powers compared to what usually is required in optoacoustics applications. In this paper, we study the operation of the HPDL devices, out of the manufacturer datasheet ratings at high current (< 40A) and short pulses (< 100ns). Two short pulse, high current drivers have been used to control the HPLDs. We have obtained optical peak powers of 257 W and energies per pulse of 5.2 µJ at 20 ns optical pulse duration with a single HPDL chip and using a four HPDL chips array, we have achieved optical peak powers of 750 W and energies per pulse of 31.2 µJ at 40 ns optical pulse duration. This new operating regimen improves the performance of HPDL for optoacoustic biomedical imaging techniques.