Controllable Burst-Mode Nd3+:YAG/Cr4+:YAG Laser Pumped by 808 nm Polarization-Combined Laser Diodes

This paper presents a time-shared pumping technology for semiconductor lasers based on polarization-combined technology, which enables a compact passively Q-switched Nd3+:YAG/Cr4+:YAG laser to generate tunable pulse sequence output. Two 808 nm laser diodes (LDs) with high polarization were integrated into a casing system measuring 61.5 mm × 32 mm × 12.5 mm through the implementation of fast and slow axis collimation, polarization-combined, and beam-shaping techniques. The study introduces a temporal modulation function to the electrical driving signals, allowing for synchronous and delayed control of the two laser pump sources. By adjusting the pumping delays (200 μs, 240 μs, 280 μs, and 320 μs), two types of pulse sequences combined by “1 + 1” and “2 + 2” at 1064 nm were successfully generated. Experimental results demonstrated that the energy and intensity of each sub-pulse within the burst-mode remain stable throughout the entire sequence, with adjustable sub-pulse interval. Furthermore, the laser system exhibited good beam quality with near-diffraction-limited output characteristics (M2 < 1.5). In general, the tunable pulse sequence laser source offers significant potential for applications in high-precision laser processing, laser ranging and precision measurement, demonstrating its broad application potential.