Absolute distance interferometry capable of long-term high frequency measurements of fast targets

Thesis

This thesis presents two novel absolute distance measurement techniques which expand the recently developed dynamic frequency scanning interferometry method [1][2][3]. Preliminary work to improve the frequency referencing of the techniques will also be reported.
The first method was developed to eliminate gaps in the distance measurement which were present in previous approaches and is referred to as continuous frequency scanning interferometry (continuous FSI). This technique has been successfully demonstrated on stationary targets at a range of 2.5–5 m and moving targets at speeds around 2 mm/s and 8 mm/s.
The second method is referred to as enhanced continuous FSI (enhanced CFSI). It addresses one of the main limitations of the continuous FSI technique by greatly increasing the allowable target motion speed. Proof of principle measurements of enhanced continuous FSI have been performed at speeds of up to 16 mm/s and are presented here.
The improved frequency referencing technique uses an optical nanofibre to perform saturated absorption spectroscopy of acetylene-13. The equipment, experimental procedure and preliminary results are presented.

Authors: Lancaster, AJ

• DOI: 10.5287/ora-orn9apgwq
• Type of award: DPhil
• Level of award: Doctoral
• Awarding institution: University of Oxford
• Language: English
• Keywords: absorption spectroscopy; absolute distance measurement; metrology; laser interferometry
• Subjects: Physics