Interference Miore Contrast Enhancer by docphoton

Last crawled date: 3 years, 3 months ago

Interference pattern weak? and not near the bullseye? Fuggeddaboudit! You can still significantly enhance your measured fringes by convolving the interference pattern against this adjustable mask. Fits in a 1'' optic mount, just put it before the detector, and by adjusting the relative positions of the two screens you create Miore fringes that get close to matching the incident interferogram, at which point you will have greatly increased the measured fringe contrast.
In the graph is output of an interferometer with an actuated phase plate (see the phase plate design, also by docphoton) going rythmicaly back and forth across nearly 2\pi phase. Shown is the signal on a PD with and without the mask. Using the mask makes the signal darker (of course) but increases the fringe contrast from about 12% to close to 45%. This increased contrast leads to a more precise determination of the phase difference change.
Print at 60% for best results.