Limiting fringe pointing precision in a scanning two-beam interferometer.
The limiting fringe pointing precision obtainable from a scanning two-beam interferometer is calculated. A photoelectric fringe visibility is derived. If this is high, significantly higher precision is obtainable by pointing on a dark fringe rather than a bright fringe. Optimum relative width of the slit used for viewing straight fringes and optimum scan amplitude are calculated for the fixed fringe spacing and fixed slit width cases. Different results are obtained for dark and bright fringes. Results are given in a form enabling rapid experimental optimization of a scanning two-beam interferometer. Experimental measurements show satisfactory agreement with the theory.
Raymond
O J
OJ