Project Type: EngD

Supervisor: Dr Michael Lengden

Project Description

This project will address the urgent requirement for new photonics tools to police stricter greenhouse gases (GHG) emission standards. In particular, development of cost-effective photonics tools to improve accuracy and simplify the design of sensing systems for air quality monitoring and real-time spectroscopy in the liquid and gas phase for analytical science applications will be targeted. These tools will be based on new diode-pumped laser sources for oscillation in the 3-5 um region (by direct laser oscillation) and 8-10 um spectral range (after frequency down-conversion).

Extending the wavelength coverage of direct diode-pumped lasers, while maintaining the high wall-plug efficiency of these devices, requires an understanding of the underpinning device science:

  • Laser-related parameters and cross-relaxation mechanisms allowing increased pump power conversion efficiency;
  • Identification of “athermal” directions in crystals to minimise the thermal lens strength.

Practical application of the developed laser systems in 3-10 um spectral region, determines engineering challenges to be addressed during the project:

  • Frequency combs generation in mode-locked systems
  • Narrow–linewidth high energy laser oscillation and amplification
  • Applicability of developed frequency comb systems for use in dual-comb spectrometer for real-time analytical spectroscopy.

New laser systems based on low phonon energy halide crystals giving output in the infra-red (3-10 um) spectral range for application in stand-off sensing of air pollution and for real-time IR dual-comb spectroscopy will be studied, built and tested, with the input from Caledonian Photonics Ltd being integrated into the work plan. Development of diode-pumped solid-state lasers directly emitting at these wavelengths would simplify such laser systems, making them cheaper and more reliable. In addition, compact diode-pumped laser sources in this range would pave the way for chip-size dual-comb spectrometers for high-resolution real time analytical spectroscopy.

A combination of laser spectroscopy and laser engineering will be at the core of this project:

  • systematic laser spectroscopy of Pr, Er and Dy doped low-phonon energy halides;
  • complex study of thermo-optical properties of low-phonon energy halides for different orientations w.r.t. the optical indicatrix;
  • Q-switching, mode-locking, frequency down-conversion and narrow-linewidth laser amplification using novel Dy, Er and Pr doped low-phonon energy halide laser crystals.

Complex laser spectroscopy of new laser materials suitable for oscillation in mid-IR spectral range under direct diode pumping, challenging laser engineering of ultrafast and narrow-linewidth giant pulse laser systems in this range, as well as subsequent applicability tests of developed devices for dual-comb spectroscopy makes this project an exciting new opportunity for an EngD student.

The EngD student will work in the Technology and Innovation Centre, Glasgow, where the academic (Electronic & Electrical Engineering Department, University of Strathclyde) and one of the industrial partners (Fraunhofer Centre for Applied Photonics) have research laboratories. Laser development will be carried out in close collaboration with the second industrial partner of the project – Caledonian Photonics.

CDT Essential Criteria

A Masters level degree (MEng, MPhys, MSc) at 2.1 or equivalent.

Desire to work collegiately, be involved in outreach, undertake taught and professional skills study.

Project Essential Criteria

A Masters level degree (MEng, MPhys, MSc) at 2.1 or equivalent.

Desire to undertake an experimental project which involves working with lasers and spectroscopic studies.

Desire to interact with external end-users of the developed technology.

Project Desirable Criteria

Background in lasers. Computer modelling or programming skills.