Thorlabs' high-precision, AR-coated, right-angle prism can be used to deviate a light path by 90° or 180°, depending on which surface is used as the input for the light source.

Due to total internal reflection (TIR), the right angle prism can be used as a 90° reflector. When the input light is incident on one of the prism's legs, it undergoes TIR at the glass/air boundary of the hypotenuse and exits via the other prism leg. This 90° deviation of the input light makes the right angle prism a suitable alternative for a mirror. The right angle prism can be used as a 180° retroreflector. When the input light is incident on the face of the hypotenuse, it undergoes total internal reflection (TIR) at the glass/air boundary at the prism legs. It undergoes TIR a second time at the next prism leg and exits the hypotenuse in a path parallel to that of the input beam. Like the retroreflector, the 180° deviation of the light path is independent of the angle at which the light enters the prism.

• Clear Aperture: 70%
• Surface Quality (Scratch-Dig): 40-20
• Surface Flatness @ 633 nm: ?/10
• Number of Polished Faces: 3 (triangular faces are fine ground)
• Material: N-BK7
• A = B: 20 mm
• C: 28.3 mm
• H: 20 mm
• Angle Tolerance: ±3 arcmin
• AR Coating: 350 - 700 nm, Legs