Lasers and photonics

Supervisor: Professor David Spence

Topic description

This PhD project would work with the team developing our unique Raman water sensing LiDAR system, further refining and extending its capabilities to remotely measure water properties including temperature, salinity and turbidity.

The project could include both experimental and theoretical components.

Experimental work would involve:

• improving signal collection and calibration
• testing sub-degree temperature retrieval
• upgrading the existing laser-based sensing platform
• validating performance across laboratory and field conditions.

Theoretical work could include:

• developing advanced data inversion algorithms to extract temperature, optical properties and water quality indicators from complex optical returns
• FPGA-accelerated Monte Carlo simulations of light propagation in water
• incorporating scattering, absorption, fluorescence and Raman return signals.

A key aim would be to move the technology closer to practical use, including prototype refinement, commercialisation pathways, industry engagement and the development of intellectual property for deployable marine, environmental or industrial sensing systems.

Supervisor: Professor Richard Mildren

Topic description

A PhD position is available in the area of ultra-stable laser physics and optical frequency control. The project will investigate compact monolithic diamond Raman lasers with ultra-narrow linewidths for next-generation optical atomic clocks and precision sensing.

The research combines nonlinear optics, laser stabilisation, photonics and advanced optical materials, with opportunities to work on state-of-the-art frequency metrology and international collaborations in optical clocks and quantum technologies.

The successful candidate will get to work within a highly collaborative research environment and develop expertise in:

• feedback control
• high-performance laser systems
• photonics engineering
• precision measurement.

This project is suitable for applicants with a background in:

• electrical engineering
• optics
• photonics
• physics
• a related discipline.

Supervisor: Professor Alexander Fuerbach

Topic description

In collaboration with HB11 Energy, this PhD project will contribute to the development of laser-driven fusion energy technologies with the potential to provide commercially viable, globally deployable clean energy.

The project will focus on the theoretical and numerical modelling of direct-drive inertial confinement fusion (ICF) using deuterium-tritium (D-T) fuel.

In direct-drive ICF, high-energy laser beams irradiate the outer surface of a spherical target capsule. The resulting ablation drives the capsule inward at extreme velocity, compressing the D-T fuel to the high densities and temperatures required for ignition and thermonuclear burn.

The candidate will investigate advanced target designs incorporating a central gas-filled region surrounded by cryogenic solid D-T fuel layers and ablator materials. Particular emphasis will be placed on larger target concepts that may offer improved energy gain and contribute to the techno-economic viability of future inertial fusion energy systems. Cryogenic D-T target implosions and direct-drive target architectures are established elements of inertial fusion research.

The modelling program will initially employ one-dimensional radiation-hydrodynamic simulations to study:

• ablation dynamics
• fuel compression
• hot-spot formation
• implosion velocity
• laser energy coupling
• predicted fusion yield
• shock propagation.

The work will subsequently extend to two-dimensional simulations to assess effects including:

• implosion asymmetry
• irradiation non-uniformity
• the growth of hydrodynamic instabilities.

Selected target designs may later be investigated in three dimensions, subject to scientific need and computational feasibility.

Where appropriate the project will also use kinetic and particle-in-cell (PIC) modelling to examine laser-plasma interactions, energetic-particle transport and other processes not adequately represented by hydrodynamic modelling alone. Established hydrodynamic and PIC simulation packages are available to support the research.

This project will suit a student with an interest in plasma physics, high-energy-density science, numerical modelling and the development of transformative clean-energy technologies as well as a strong background in:

• applied mathematics
• computational science
• physics
• a related discipline.

Supervisor: Professor Alexander Fuerbach

Topic description

A PhD project is available to develop a new generation of compact mid-infrared hyperspectral imaging systems capable of detecting and mapping chemicals through their unique molecular absorption signatures.

Hyperspectral imaging records a spectrum at each spatial location, allowing materials, gases and pollutants to be identified remotely. However, current compact hyperspectral imagers operate predominantly in the visible and near-infrared spectral regions.

Extending this capability into the mid-infrared molecular fingerprint band would provide much stronger and more selective access to the vibrational signatures of many molecules, including environmentally important gases such as methane and nitrogen oxides.

This project will investigate an integrated photonic platform for hyperspectral imaging across the 3-7 µm wavelength range, replacing bulky free-space optical instrumentation with miniaturised, robust photonic chips.

The core concept is to use femtosecond-laser direct writing to fabricate three-dimensional waveguide circuits in mid-infrared-transparent fluoride glasses. These waveguides will form interferometric arrays for compact Fourier-transform or spatial-heterodyne spectroscopy and will ultimately be combined with mid-infrared detector arrays to enable real-time imaging.

The successful candidate will contribute to the full device-development cycle:

1. numerical modelling of waveguides and interferometric architectures
2. optimisation of femtosecond-laser fabrication parameters
3. optical characterisation of written photonic structures
4. integration of the resulting chips into a proof-of-concept hyperspectral imaging system.

Key research questions will include how to:

• achieve high spectral resolution in a compact footprint
• control phase errors and cross-talk in complex three-dimensional photonic networks
• maximise refractive-index contrast while maintaining low propagation loss.

The project offers training at the interface of ultrafast laser fabrication, integrated photonics, infrared spectroscopy and optical instrumentation.

Its outcomes could enable highly compact chemical imaging instruments for applications in atmospheric monitoring, industrial sensing, materials analysis and future airborne or space-based observation platforms.

Supervisor: Professor Richard Mildren

Topic description

A PhD position is available in the emerging area of self-referenced laser stabilisation and optical frequency control. The project will explore a new approach to ultra-stable lasers in which thermal drift is measured and corrected internally using stress-induced birefringence in diamond resonators.

The research spans precision photonics, laser stabilisation, nonlinear optics, and optical metrology, with applications in portable optical atomic clocks, quantum technologies, navigation and precision sensing.

The successful candidate will collaborate with leading international groups in optical clocks and precision metrology and will work on:

• advanced feedback systems
• compact resonator platforms
• dual-frequency laser operation
• frequency-noise analysis.

Applicants with backgrounds in the following areas are encouraged to apply:

• control systems
• electrical engineering
• optics
• photonics
• physics
• a related discipline.

Supervisor: Professor Alexander Fuerbach

Topic description

A PhD project is available to develop advanced ultrafast laser beam-delivery and precision-timing technologies for the AWAKE experiment at CERN.

AWAKE is the world’s first proton-driven plasma wakefield acceleration experiment and uses high-energy proton bunches from CERN’s Super Proton Synchrotron (SPS) to generate plasma wakefields capable of accelerating electron beams. Precise timing between the laser, proton beam, electron beam and diagnostic systems is essential for the experiment and for the development of future plasma-based accelerator technologies.

The project uses:

• accelerator instrumentation
• dispersion engineering
• fibre Bragg grating design and fabrication
• precision optical metrology
• ultrafast photonics.

The project will investigate the distribution of ultrafast optical timing pulses between spatially separated locations in the AWAKE experimental and associated SPS timing infrastructure. Optical-fibre delivery offers a compact, robust and alignment-insensitive solution, but propagation through long fibre links introduces chromatic dispersion and environmentally induced delay drift, both of which must be carefully controlled to preserve femtosecond-level timing performance.

A central research objective will be the development of femtosecond-laser-inscribed chirped fibre Bragg gratings for tailored dispersion compensation and recompression of fibre-delivered ultrafast pulses. These pulses will provide precise optical fiducials for beam diagnostics and timing measurements.

The project will also investigate active stabilisation of the fibre links using timing-control technology developed in collaboration with CERN, with the objective of achieving diagnostic timing stability well below 50 femtoseconds across the relevant AWAKE experimental infrastructure.

The successful candidate will:

• have the opportunity to translate laboratory-developed photonic technology into a demanding large-scale scientific facility
• spend time at CERN, near Geneva, implementing and fully characterising the developed system in the AWAKE environment.

Supervisor: Professor Richard Mildren

Topic description

Diamonds have highly unusual and extreme properties that are ideal for creating a new class active laser components with potential applications ranging from biomedicine, defence and environmental sensing.

We are seeking a PhD student to create and investigate waveguide diamond Raman lasers systems. The candidate will have the opportunity to fabricate novel waveguide structures in diamond and test their performance in laser configurations.

You will join a large team of researchers aspiring to break new ground in:

• diamond optics
• micro-optical systems
• nonlinear Raman interactions.