My work

(Under construction)

The Michelson beam combiner is a device that interferes two or more collimated beams of light from a common source by use of beam splitters. The output consist of two or more combined beams, whose intensity depend on the path difference from the source along each beam, as well as on any difference in perspective associated with angular structure on that source. When the differential delay is equalised along all interfered beams, we minimise any reduction in fringe contrast due to the temporal coherence of the viewed source. At the centre of the fringe envelope we can then scan a fringe through small changes in the differential delays. The scanning is performed by the fringe modulators. The modulators modulate small delay changes into the input beams, incorporating different rates for each beam, so to encode all fringe component at different fringe rates.

I work mostly on fringe modulation and visibility extraction.

Following figure shows how an ideal four-way fringe modulation should look like.

The modulation function is linear across the sweep and covers an integer number of fringes.

This ideal case extremely hard to achieve for a multi-way beam-combiner

and at the high frequency of 1kHz/sweep required to freeze out the atmospheric wave-front.

The result is the significantly less than linear modulation function and distorted fringe shape that follows:

I also work on image reconstruction and simulations investigating the importance of bispectrum coverage in

model-free optical aperture synthesis imaging.

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Model