Development of a cryogenic 2 μm multi-pass amplifier in nanosecond regime

Identifier:  TDX:3189

Handle: https://hdl.handle.net/20.500.11797/TDX3189

Authors:  Yue, Fangxin

Abstract:
Motivated by the increasing application demands on the 2 μm high average/peak power lasers, this thesis is devoted to develop a cryogenic 2 μm multi-pass amplifier in the nanosecond regime based on the Tm:Y2O3 transparent ceramics. To reach this goal, the active medium Tm:Y2O3 transparent ceramic was well studied and the master oscillator power amplifier concept was employed for developing the cryogenic laser system. This work is divided into 7 chapters. Chapter 1 introduces the current state-of-the-art of the 2 μm pulsed lasers as well as the motivation and objectives of this dissertation. Chapters 2, 3 and 4 describe the characterization of the active medium Tm:Y2O3 transparent ceramic in terms of material structure, cryogenic spectroscopy, and continuous-wave lasing potential, respectively. From those studies, crucial laser design parameters, such as the exact pump/lasing wavelength, lifetime, gain factor, etc., were obtained. Chapter 5 presents the demonstration of a master oscillator, which served as the seed source for the amplifier stage. Chapter 6 shows the energy scaling via the multi-pass amplifier in two different geometries. Finally, chapter 7 summarizes the achieved results and outlooks the future research.