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Dysprosium mid-infrared fibre lasers

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thesis
posted on 28.03.2022, 21:20 authored by Matthew Majewski
Optical sources in the mid-infrared have enabled an increasing number of applications in fields such as sensing, materials processing, and defence. While traditional mid-IR sources have often been based on nonlinear conversion in parametric oscillator devices, these systems are bulky, costly, and inefficient. In contrast, the past few decades have seen uoride glass based mid-IR fibre lasers advance from small scale laboratory demonstration, to advanced developmental systems, and even recently commercial products. The majority of this class of lasers have been based on erbium, or to a lesser extent, holmium-doped gain media. Both systems have achieved multi-watt output power, and have been demonstrated as ultra-fast pulsed systems down to pico- and even femto-second pulse duration. However, these systems share two fundamental limitations. One, the conversion efficiency is limited to less than 50%, which has led to a distinct slowdown in output power scalability. Two, both systems are limited in bandwidth, translating to holes in the optical spectrum which can be covered by fibre lasers. There is a third dopant element which exhibits emission in the same spectral region, but has been largely ignored: dysprosium. While the few demonstrations of dysprosium-doped mid-IR fibre lasers did not exceed performance of competing systems, there is much untapped potential remaining which is what this thesis aims to address. Specifically, two novel optical pumping schemes based on near- and mid-infrared are investigated which address the limitations of the previous dysprosium efforts, and the competing erbium and holmium basedsystems. Further, the viability of progressing these systems to operation in the pulsed regime is considered. As a whole, these investigations aim to both solidify dysprosium as a viable candidate for mid-IR fibre laser emission, and deepen the collective understanding of dysprosium as an active rare earth dopant.

History

Table of Contents

1. Introduction -- 2. Dysprosium and the rare earth dopants -- 3. Theory : optical fibre and lasers -- 4. In-band pumping at 2:8µm -- 5. Pumping at 1.7µm - source development -- 6. Near infrared pumping of dysprosium -- 7. Conclusion -- References.

Notes

Empirical thesis. Bibliography: pages 93-103

Awarding Institution

Macquarie University

Degree Type

Thesis PhD

Degree

PhD, Macquarie University, Faculty of Science and Engineering, School of Engineering

Department, Centre or School

School of Engineering

Year of Award

2018

Principal Supervisor

Stuart D. Jackson

Rights

Copyright Matthew Majewski 2018. Copyright disclaimer: http://mq.edu.au/library/copyright

Language

English

Extent

1 online resource (xiv, 103 pages) colour illustrations

Former Identifiers

mq:70634 http://hdl.handle.net/1959.14/1266201