Advanced Dual-Comb LiDAR: Precision 3D Metrology for Advanced Sustainable Manufacturing

About the Project

We are seeking to appoint a talented PhD candidate to join the Ultrafast Optics Group at Heriot-Watt, to start by 1 October 2026, to develop a faster and more sensitive implementation of dual-comb ranging—an optical metrology technique combining interferometry-like precision with time-of-flight accuracy.

Summary

The project is hosted at Heriot-Watt University but is co-sponsored by our partner AWE Nuclear Security Technologies, and is expected to involve some short secondments to their facility in Aldermaston.

Heriot-Watt has developed a LiDAR-like version of dual-comb ranging, in which each distance measurement is reduced to just one precision time-stamp. In this way, our dual-comb LiDAR approach reduces the data burden of interferometric dual-comb ranging by several orders of magnitude, opening the way to continuous data streaming, ultrafast measurements and rapid imaging.

Further details of our previous research in this area are contained in our patent and associated paper, and subsequent publications detailing multiple-target and non-cooperative-surface configurations.

AWE Nuclear Security Technologies have an interest in applying dual-comb LiDAR for measuring both static and dynamic assemblies. This experimentally-based PhD project will address limitations in the current state-of-the-art of dual-comb ranging techniques, which still lack the speed, sensitivity and versatility of conventional LiDAR, restricting their practical application.

Motivated specifically by the needs of end-users in the advanced manufacturing sector and specifically by the use-cases proposed by AWE, we aim to address these limitations by enhancing dual-comb ranging with single-photon detection, to realise sub-µm precision ranging and imaging from diffuse surfaces at 100 kHz single-point update rates.

Research activities in more detail

The research project aims at a number of innovations that will lead to publishable results and ultimately will be of interest to AWE's business:

(1) Improving the sensitivity of dual-comb LiDAR

Our existing system utilises a two-photon gated photodiode to generate accurate temporal measurements from the system. Efficient nonlinear optical frequency conversion techniques will be combined with sensitive detectors to improve the sensitivity of the dual-comb LiDAR approach.

(2) Assembly of dual-comb high-repetition-rate Er,Yb:glass lasers.

A laser-development aspect of the project will be to create a practical and transportable dual-comb system based on work emerging from the group that has realised a highly stable 1.56 µm ultrafast laser with direct application to dual-comb metrology. We will construct and configure this system to provide the repetition rate stability needed for high precision dual comb measurements.

(3) Improved clocking electronics

Previously utilised electronics utilised a microcontroller operating essentially as a stopwatch to measure arrival times of the measured photons. A LiDAR specific system will be implemented using higher-precision electronics which will improve temporal resolution to take advantage of the sensitivity and repetition rates previously discussed.

(4) Demonstration of accuracy (static)

The resulting dual-comb system will provide sub-micron distance accuracy at high speed. This will be demonstrated on a static system (for metrology) deemed a suitable analogy for AWE metrology applications i.e. similar distance, similar insertion loss, similar surface finish etc to a typical target).

(5) Demonstration of accuracy (dynamic)

The assembled system will provide the ability to determine displacement of a reflecting surface moving at high speed (km/s) enabling application to dynamic trials to be undertaken. The system will be tested on an appropriate gas gun and fielded against existing diagnostics in order to assess the performance in this regime.

About you

Suitable applicants will have a first-class undergraduate masters degree (or equivalent) in physics or other relevant discipline. Applicants not meeting this formal criterion but having compensating research experience e.g. in industry, will also be considered.

Candidates will join a diverse team of graduate and post-doctoral researchers. You should have a solid understanding of optics and lasers and have relevant experimental experience, for example through an undergraduate research project or research internship.

While experimentally-led, the project will also include computational components, so experience in scientific programming for data analysis and capture, e.g. using Matlab or Python, is also valuable.

How to apply

Interested candidates should begin by emailing Prof. Derryck Reid (D.T.Reid@hw.ac.uk) to arrange an informal call to discuss the project in more detail. Formal applications must be made through the Heriot-Watt on-line application system, https://www.hw.ac.uk/study/apply/uk/postgraduate.htm.

Start date

The project will start on 1 October 2026.

Funding Notes

Full funding, covering fees and stipend (in line with UKRI values), is only available for applicants who are UK nationals; have settled status; have pre-settled status (meeting residency requirements); have indefinite leave to remain or enter, or are otherwise eligible for Home fee status.

This project is funded by Heriot-Watt's Strategic EPSRC Doctoral Landscape Account (DLA). The student will receive an enhanced stipend of £2,500 per annum above the standard EPSRC rate.

References

US Patent Application US20240012143A1, "Apparatus and method for distance metrology"
Two-photon dual-comb LiDAR
Hollie Wright, Jinghua Sun, David McKendrick, Nick Weston and Derryck T. Reid,
OPTICS EXPRESS 29, 37037-37047 (2021).
Multi-target two-photon dual-comb LiDAR
Hollie Wright, Alexander J. M. Nelmes, Nick J. Weston, and Derryck T. Reid
OPTICS EXPRESS 31, 22497-22506 (2023).
Two-photon dual-comb LiDAR for precision ranging to non-optical targets
Hollie Wright, Alexander J M Nelmes and Derryck T Reid
J. PHYS. B: AT. MOL. OPT. PHYS. 58, 105402 (2025).