Composite, all-ceramics, high-peak power Nd:YAG/Cr^4+:YAG monolithic micro-laser with multiple-beam output for engine ignition

TLDR

This laser can be used for multi‑point ignition of an automobile engine. A single active laser source made of a composite, all‑ceramics Nd:YAG/Cr(4+):YAG monolithic cavity was pumped by three independent lines. The passively Q‑switched Nd:YAG/Cr(4+):YAG micro‑laser produced three beams with ~2.4 mJ energy, 2.8 MW peak power, and an M2 of 3.7, enabling stable air breakdowns; raising the pump repetition to 100 Hz increased pulse energy by 6 % with a similar pump energy rise, and pulse timing could be tuned within 5 % to allow simultaneous multi‑point ignition.

Abstract

A passively Q-switched Nd:YAG/Cr(4+):YAG micro-laser with three-beam output was realized. A single active laser source made of a composite, all-ceramics Nd:YAG/Cr(4+):YAG monolithic cavity was pumped by three independent lines. At 5 Hz repetition rate, each line delivered laser pulses with ~2.4 mJ energy and 2.8-MW peak power. The M(2) factor of a laser beam was 3.7, and stable air breakdowns were realized. The increase of pump repetition rate up to 100 Hz improved the laser pulse energy by 6% and required ~6% increase of the pump pulse energy. Pulse timing of the laser-array beams can by adjusted by less than 5% tuning of an individual line pump energy, and therefore simultaneous multi-point ignition is possible. This kind of laser can be used for multi-point ignition of an automobile engine.