High-efficiency 60 W TEM_00 Nd:YVO_4 oscillator pumped at 888 nm

Abstract

We propose a technique for pumping Nd:YVO(4) with high optical power at 888nm while making absorption independent of the pump light polarization state. This is especially suitable for systems end pumped by high-power, high-brightness fiber-coupled diode sources associated with long vanadate crystals to effectively spread the heat load in a large volume. A compact 60 W output, 55% optical efficiency cw TEM(00) oscillator was demonstrated.

Highly efficient Nd:YVO_4 laser by direct in-band diode pumping at 914 nm

“…By the use of a polarizer put in our pump beam, we measured an absorption slightly higher along the c axis than along the a axis (␣ c = 0.65 cm −1 and ␣ a = 0.46 cm −1 , respectively). It is far from the strong difference between the two axes at 808 nm [3], and it is very similar to the absorption polarization properties at 888 nm. As mentioned in [3], this nearly unpolarized absorption is an asset to avoid the polarization control of the pump source.…”

“…In fact, reduction of the quantum defect induced by in-band pumping around 880 nm represents one of the best methods for power scaling of Nd: YVO 4 while maintaining an excellent beam quality. First demonstrated under Ti:sapphire pumping [2], this concept has been successfully derived with high-power laser diodes in a large number of configurations [3][4][5]. In this way, it is possible to go further, as 880 nm is not the longest wavelength of the absorption band.…”

Non-Pulse-Leakage 100-kHz Level, High Beam Quality Industrial Grade Nd:YVO4 Picosecond Amplifier

“…The pumping of Nd:YVO 4 with 888 nm LD induces less thermal stress gradient along the crystal compared with 808 nm that makes it possible for long time operation of the laser with higher stability [20,21]. Table 1 presents the physical parameters of Nd:YVO 4 crystal pumped by 808 nm and 888 nm wavelengths [22,23]. As the data show, the lower fractional thermal loading in 888 nm pump compared with 808 nm wavelength results in the heat reduction and optical efficiency growth.…”

Four-Dimensional Thermal Analysis of 888 nm Pumped Nd:YVO4 Dual-Rod Acousto-Optic Q-Switched Laser

“…As a new generation of in-band pumped neodymium lasers with a low-quantum-defect, 888 nm pumped Nd:YVO 4 lasers have drawn much attention ever since it was first reported in 2006 [1], with its first high-power high-efficiency Master Oscillator Power-Amplifier (MOPA) system built in 2007 [2]. Nd:YVO 4 enjoys large absorption and stimulated emission cross sections that may easily lead to high gain but weak thermal property due to the low thermal conductivity and high energy transfer upconversion (ETU) coefficient.…”