We present an efficient zero-phonon-line pumped cryogenic Yb:YAG laser passively Q-switched by Cr:YAG with different initial transmissions. At 140K, with 85% initial transmission of Cr:YAG, a maximum average output power of 5.19 W with a repetition rate of 24.7 kHz was achieved leading to a slope efficiency of 55.7%. The maximum pulse energy, minimum pulse width and peak output power obtained in this case were 0.21 mJ, 142 ns and 1.48 kW respectively.
In this work, we have shown the possibility of performing pulsed laser operation at cryogenic temperature with innovative modular compact laser cavity. Using Yb:YAG/Cr:YAG configuration, at cryogenic temperature, in the preliminary laser experiments, we obtained a maximum average output power of 2.7 W with a repetition rate of around 50 kHz. The minimum pulse width, maximum pulse energy and peak power obtained were 2.5 ns, 60 μJ. and 25 kW respectively. To the best of our knowledge, an experimental approach on compact pulsed Q-switched lasers based on Yb:YAG/Cr:YAG at cryogenic temperature is tried for the first time.
In recent years, there has been a vast development of high energy class lasers of the order of 100 J to kJ level which have potential applications in the field of science and technology. Many such systems use the gain media cooled at cryogenic temperatures which will help in enhancing the spectroscopic and thermo-optical properties. Nevertheless, parasitic effects like amplified spontaneous emission enhance and affect the overall efficiency. The best way to suppress this effect is to use cladding element attached to the gain material. Based on these facts, this work was focused on the systematic investigation of temperature dependent absorption of several materials doped with transition metals, which can be used as cladding, as laser gain material, or as passive Q-switching element. The Ti:sapphire, Cr:YAG, V:YAG, and Co:MALO samples were measured in temperature range from 80 K to 330 K by step of 50 K. Using Beer-Lambert law we estimated the absorption coefficient of these materials.