Thesis

Directly diode-laser-pumped titanium-doped sapphire lasers

Creator
Rights statement
Awarding institution
  • University of Strathclyde
Date of award
  • 2012
Thesis identifier
  • T13225
Qualification Level
Qualification Name
Department, School or Faculty
Abstract
  • Titanium-doped sapphire is one of the most versatile laser gain materials. Tunable between 0.7 m and 1.1 m and capable of generating femtosecond pulses, the Ti:sapphire laser has become an important tool for many applications. Its ubiquitous use across many scientific disciplines is increasingly complemented by commercial applications including imaging, spectroscopy, micro-processing of materials and the generation of terahertz radiation. However, today's Ti:sapphire lasers are complex, bulky and expensive, leaving many applications unaddressed, particularly where lower costs and smaller footprints are vital. The biggest hurdle to smaller and cheaper Ti:sapphire lasers is the pump light source - typically a frequency-doubled, multi-watt neodymium or optically pumped semiconductor laser. Ideally, such intricate and expensive pump lasers would be replaced by compact, robust and cheap diode lasers. Two factors have prevented this: first, Ti:sapphire has a broad but relatively weak absorption in the blue-green region of the spectrum where high-power diode lasers are not currently available; and second, the very short upper laser level lifetime of Ti:sapphire and relatively large parasitic losses result in a high intrinsic laser threshold. Combined, these factors strongly favour high-brightness pump sources. The recent progress in diode lasers based on gallium nitride materials now opens the way to challenge the perceived wisdom that Ti:sapphire cannot be diode-pumped. In this work diode-laser pumping of Ti:sapphire lasers has been shown to be possible. The world's first diode-laser-pumped Ti:sapphire laser has been developed, enabling drastic reductions in cost and size over current systems. Using innovative approaches to exploit gallium nitride diode lasers as the pump source, both continuous-wave operation and generation of femtosecond pulses have been demonstrated. As a result, some of the unrivalled performance of today's high-cost, lab-bound Ti:sapphire lasers may soon be available at a fraction of the current cost and footprint.
Resource Type
DOI
Date Created
  • 2012
Former identifier
  • 947885

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