No-Fourier-Transform Optical Coherence Tomography

This seminar will be followed by tea, coffee and biscuits in the DB crush area.

Abstract

In order to process the signal in spectral domain optical coherence tomography (OCT), processing of the photodetected signal to infer depth resolved information proceeds via a Fourier transform (FT). I will present a method of spectral domain OCT, that we termed as Master Slave (MS) OCT, that operates with no structural FT block. The MSOCT: (i) allows direct access to the information from selected depths in the sample placed in the OCT interferometer; (ii) eliminate the process of resampling, required by the FT based conventional technology, with immediate consequences in improving the decay of sensitivity with depth, achieving the expected axial resolution limit, reducing the time to display an en-face OCT image, lowering the cost of OCT assembly and (iii) presents tolerance to the dispersion left unbalanced in the OCT interferometer.

I will then illustrate the value of the new method in assembling OCT systems as well as some of its applications, including downconversion OCT. This method allows real time production of en-face OCT images using ultrafast tunable lasers at over tens of MHz tuning rates, so fast that no digitiser can allow real time production of cross section OCT images.