Prof Esser has achieved excellent research accomplishments through his focussed research on diode-pumped solid-state lasers and has produced journal papers and invited international conference papers, many of which have been cited by international researchers. His research background include key demonstrations of Nd-doped systems for 1 µm operation (Nd:YLF and Nd:YVO4), Tm-doped systems at 1.9 µm (Tm:YLF, Tm:GdVO4) and Ho-doped lasers and amplifiers for high energy 2 µm operation (Ho:YLF, Ho:LuLF). These lasers could be applied to defence, remote sensing and industrial processes. In addition to his publication outputs, he was also co-author and principle investigator for a number of technology demonstrators developed during industry-focussed research projects.
Prof Esser is Principle Investigator for one of the core projects of the EPSRC Centre for Innovative Manufacturing in Laser-based Production Processes. The project is entitled “High energy amplifiers for ultrafast lasers” and is supported by the industrial collaborator Rofin-Sinar UK (http://www.rofin-uk.com/). This project is part of the research theme of high average power ultra-fast laser technologies that investigates the technologies underpinning the development of new commercial ultra-fast pulse lasers at high (kW) average powers with spectral outputs in the IR, visible and UV. The focus is on device architectures which allow power scaling to the kW range for trains of laser pulses with durations in the range 0.5 ps to 10 ps. Research include the integration of new ultra-fast pulse laser oscillators, aiming for high stability and to minimise component count and laser footprint.
Power amplification strategies are evaluated, including modern gain medium structures. High power multi-bar diode laser pump strategies with novel techniques for beam combining with maintained beam brightness are investigated as laser amplifier pump sources. Particular attention is devoted to design and fabrication techniques to minimise manufacturing costs and maximise system efficiency.
Another research theme pursued by Prof Esser is new materials and architectures for mid-infrared solid-state lasers, which aims to address the latest developments of solid-state laser systems operating in the mid-infrared wavelength range (from 2 µm to 8 µm). The emphasis is on demonstrating outstanding performance in terms of power and energy scaling, as well as high-efficiency systems which could find application in various industries. New host materials for Tm- and Ho-doped lasers operating at 2 µm are being investigated. The latest high-brightness laser diode technology is utilised as pump sources, as well as highly-customised beam correcting optics to demonstrate high-efficiency 2 µm laser systems. Conversion techniques, based on modern non-linear crystals and other device architectures, could be used to convert further into the infrared. The experimental research is underpinned by mathematical modelling and simulation of the required laser device physics, which is also applicable to a wider range of laser systems.
With support from our core industry partners SELEX-ES and Rofin-Sinar UK Ltd, PhD studentships and Post-Doctoral Research Associate positions will be made available within these research themes.
Prof Daniel Esser has a relentless passion to see new technological developments in diode-pumped solid-state lasers to be adopted by industry.