Passively Q-switched diode-pumped Cr4+:YAG/Nd3+:GdVO4 monolithic microchip laser

Abstract

: the realization of high repetition rate passively Q-switched monolithic microlaser is a challenge since a decade. To achieve this goal, we report here on the first passively Q-switched diode-pumped microchip laser based on the association of a Nd:GdVO 4 crystal and a Cr :YAG leading to a plano-plano cavity. A repetition rate as high as 85 kHz is achieved. The average output power is approximately 400 mW for 2.2 W of absorbed pump power and the pulse length is 1.1 ns.

Laser action in LaAlO3:Nd3+ single crystal

“…Lower emission cross section indicates higher threshold of laser action, but there is also a positive aspect of low emission cross section. Forget et al 22 investigated criteria of passively Q-switched laser action; they showed that very short laser pulses are obtained easier in the materials with low emission cross section.…”

Sub-5-ps, multimegawatt peak-power pulses from a fiber-amplified and optically compressed passively Q-switched microchip laser

“…Miniaturized passively Q-switched lasers, so-called microchip lasers, are capable of generating very short pulse durations. On one side, microchip lasers based on bulk saturable absorbers, mainly Cr4 :YAGs, typically generate energetic pulses with durations from some nanoseconds to several hundred picoseconds and multimicrojoule pulse energies, though the repetition rates are smaller than 85 kHz [1,2]. On the other side, the use of a semiconductor saturable absorber mirrors (SESAM) as a Q-switch shortens drastically the cavity length and, therefore, allows a significant decrease of produced pulse duration.…”

Timing-jitter reduced high-repetition-rate Q-switched Nd:YVO4/Cr4+:YAG micro laser with low pump power

“…In our case, the repetition rates from 0.8 to 1.2 MHz were observed at 1 A driving current (P LD = 640 mW at 1 A). Among the several factors governing the repetition rate [39], short cavity length (5 mm) is believed to be main factors for our high repetition rate. Figure 4 shows that if the cavity length was extended to 10 mm, which is common order in micro or microchip cavity [28], the repetition rate decreased to half.…”

“…Figure 4 shows that if the cavity length was extended to 10 mm, which is common order in micro or microchip cavity [28], the repetition rate decreased to half. And small pump beam waist (FWHM of ~59 µm horizon tal, ~27 µm vertical) at the gain medium also seems to affect for achieving high repetition rate because the repetition rate show a linear relation with pump inten sity [39,40]. When T 0 = 90% Cr 4+ :YAG and R OC = 90% output coupler were used, 1.1 MHz of repetition rate was obtained.…”