optical wedge वाक्य

Optical wedges and reflections from uncoated optical glass surfaces are used to attenuate high power laser beams.
After wringing begins, as air is slowly forced out from between the surfaces, an optical wedge forms between the surfaces.
If the surfaces are flat, but a tiny optical wedge of air exists between them, then straight, parallel interference fringes will form, indicating the angle of the wedge ( i . e . : more, thinner fringes indicate a steeper wedge while fewer but wider fringes indicate less of a wedge ).