Theoretical study of Talbot-like bands observed using a laser diode below threshold


We report on a theoretical study of an interferometric system in which half of a collimated beam from a broadband optical source is intercepted by a glass slide, the whole beam subsequently being incident on a diffraction grating and the resulting spectrum being viewed using a linear CCD array. Using Fourier theory, we derive the expression of the intensity distribution across the CCD array. This expression is then examined for non-cavity and cavity sources for different cases determined by the direction from which the slide is inserted into the beam and the source bandwidth. The theoretical model shows that the narrower the source linewidth, the higher the deviation of the Talbot bands' visibility (as it is dependent on the path imbalance) from the previously known triangular shape. When the source is a laser diode below threshold, the structure of the CCD signal spectrum is very complex. The number of components present simultaneously increases with the number of grating lines and decreases with the laser cavity length. The model also predicts the appearance of bands in situations not usually associated with Talbot bands.

Uncontrolled Keywords: interferometric system, collimated beam, broadband optical source, interception, glass slide, diffraction grating, linear CCD array, Fourier theory, intensity distribution, non-cavity source, cavity source, direction, source linewidth, visibility, laser diode below threshold
Publication ISSN: 0963-9659
Last Modified: 23 Oct 2019 11:27
Date Deposited: 12 May 2011 11:31
Published Date: 1998-05
Authors: Podoleanu, Adiran G.
Taplin, S.R.
Webb, David J.
Jackson, David A.


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