Thesis

Assessment and optimisation of a diamond master oscillator power amplifier

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Awarding institution
  • University of Strathclyde
Date of award
  • 2026
Thesis identifier
  • T17992
Person Identifier (Local)
  • 201959609
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Qualification Name
Department, School or Faculty
Abstract
  • This thesis explores the theory and design of a diamond master oscillator power amplifier (D-MOPA) as a last stage amplifier for "eye safe" range (1.5-1.6 µm) laser sources with applications in outdoor Doppler LIDAR. The main characteristic assessed is the amplification factor defined as the ratio of output to input signal. A numerical model of Raman amplification was developed to explore optimal parameters. It showed that top-hat seed pulses improve timing tolerance fourfold over Gaussian pulses, and that longer diamond samples enhance amplification (8 mm yields double the amplification of 4 mm). The model also highlighted parasitic 2nd Stokes oscillation as a key constraint and informed the choice of AR coatings for the diamond. The D-MOPA design was analysed and a proof-of-concept setup, first demonstrated by Lukasz Dsziechciarczyk, was re-characterised. Based on published results and new measurements three key limitations were identified: wavelength mismatch between the 2nd Stokes wavelength and the EDFA seed optimal range, timing jitter between pump and seed lasers and parasitic 2nd Stokes emission. To remedy the wavelength mismatch a novel 1083 nm Q-switched Nd:YAP laser using a birefringent filter was developed. It produced 500 µJ pulses of 38 ns with M2 = 1.19 and 0.9 nm linewidth. Integration of this pump source along with other optimisations such as a longer diamond sample and better synchronisation of the seed led to an improved amplification factor of ×1.15 using half the pump pulse energy. The results validate the potential of D-MOPA systems for efficient amplification in the eye-safe wavelength region. Remaining limitations were also identified such as the fragility of anti-reflection coatings on the diamond and the continued parasitic 2nd Stokes emission which offer clear directions for further improvements.
Advisor / supervisor
  • Kemp, Alan
Resource Type
DOI

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