Frequency-comb metrology for manufacturing II: Developing dual-comb distance metrology concepts and applications
Introduction: Frequency combs are the world’s most precise laser sources, with intrinsic noise measured at the 10-19 level, and celebrated in the 2005 Nobel prize to Jan Hall and Ted Haensch for their early work in developing this technology. This project is one of 3 offered in support of a new £1M initiative jointly supported by UK industry and the EPSRC to develop frequency combs to enable innovative ways to measure distance in industrial manufacturing contexts – from the curvature of mirror segments of large telescopes, to the position of machine-tools or the shape of turbine blades or aeroplane fuselages.
Technical context: This and the other 2 adjacent doctoral projects will investigate & develop complementary solutions to a distance measurement approach known as "dual-comb distance metrology", with the long term intention being to bridge the gap between precision and extended-range accuracy, providing industry with traceable & universal length-metrology. In a nutshell, we want to demonstrate an optical measurement approach that can measure the position of objects at considerable distance without sacrificing accuracy. Project description: Developing dual-comb distance metrology concepts and applications Dual-comb metrology uses two femtosecond lasers to measure the distance of a far away target with interferometric accuracy and without the limitations of traditional laser interferometry (lack of absolute distance measurement; vulnerability to fringe-counting errors etc). The technique can be implemented with or without phase-locked lasers, depending on the context, and this project will assess and develop practical schemes for dual-comb metrology which offer simultaneously high dynamic range (nanometres to metres) and high precision. The project will combine algorithm development and modelling with practical experimentation using laser sources developed at Heriot-Watt University under adjacent projects.