Wedged substrates can separate the reflected beam by the front and back surface of the substrates by the slight wedge angle. They can be used as a reference test plate for interferometers and beam samplers.
◦It can also be used as a prism to refract at a small angle. Beam deflection angle δ can be calculated refractive index n, from the wedge angle α. δ = sin−1( n sinα) − α ≒( n − 1) α ◦In BK7, 0.52 times the angle of the wedge, and in synthetic fused silica, 0.46 times the angle of the wedge. (Visible range, normal incidence)
Wedged substrates can separate the reflected beam by the front and back surface of the substrates by the slight wedge angle. They can be used as a reference test plate for interferometers and beam samplers.