2026-09-22T09:18:58Zhttps://digital.library.adelaide.edu.au/server/oai/request

oai:digital.library.adelaide.edu.au:2440/1451952025-06-13T08:09:56Zcom_2440_14759col_2440_14760

Ganija, Miftar Boyd, Keiron Rogers, Henry Duncan School of Physics, Chemistry, and Earth Sciences 2024 https://hdl.handle.net/2440/145195 Lasers operating within the 2 μm region of electromagnetic spectrum find use across a wide range of fields and applications. These include medical, material processing, LiDAR, and as pump sources for the generation of mid-infrared light. For these reasons, the aim of this research was to develop a high repetition rate, electro-optically Q-switched Ho:YAG laser capable of meeting the requirements for these applications, and as a result, investigate if it is theoretically capable of pumping an optical parametric oscillator. The basis of the research was built upon the development of a continuous-wave free-space Ho:YAG oscillator utilising a near-concentric cavity. This laser produced two emission lines at 2090 and 2097 nm, with a beam quality of M2 < 1.13. The output powers of the laser were capable of scaling up to 40 W at a slope efficiency of 62.1%, without any evidence of roll off. This laser was then adapted to be electro-optically Q-switched via the addition of an RTP Pockels cell, a quarter-waveplate, and a Brewster’s angled ZnSe window. The system was able to operate over a range of repetition rates between 8 and 11 kHz, and up to an average output power of 12.75 W at a slope efficiency of ~42.5%. The inclusion of the Q-switching intra-cavity elements caused the emission spectrum to shift to a single line at 2122 nm. The laser’s output scaled up to pulse energies of 1.59 mJ and durations of 40.5 ns, which enabled peak powers on the order of 37 kW. Finally, a range of modelling was undertaken in regard to a ZGP based doubly resonant optical parametric oscillator. This modelling indicated that the operational threshold of a theoretical OPO is able to be met by the output powers of the Q-switched 2.1 μm laser, without exceeding the damage threshold of the system. Thesis (MPhil) -- University of Adelaide, School of Physics, Chemistry, and Earth Sciences, 2025 en Lasers Optics Ho:YAG Electro-optics Q-switch Development of a High Repetition Rate, Electro-optically Q-switched Ho:YAG Laser Thesis This electronic version is made publicly available by the University of Adelaide in accordance with its open access policy for student theses. Copyright in this thesis remains with the author. This thesis may incorporate third party material which has been used by the author pursuant to Fair Dealing exceptions. If you are the owner of any included third party copyright material you wish to be removed from this electronic version, please complete the take down form located at: http://www.adelaide.edu.au/legalsopen.access