A Right-Angle Prism is a triangular block of glass with a 90-degree vertex angle and two orthogonal sides. Right-angle prisms are often used to redirect light at 90° or 180°. The deviation of the light path is done utilizing the principle of total internal reflection (TIR) at the interface of glass to air. As one selects a different entrance side to project light onto the right-angle prism, the degree to which the light path departs will also change.

If the light is incident on one perpendicular side of the right-angle prism, it undergoes a 90° redirection in the light path at the hypotenuse face and emerges at the other perpendicular side. When one needs to realize 90-degree light redirection, a right-angle prism is a much more cost-effective alternative for applications like periscopes or telescopes than a dielectric mirror with easier alignment. If the light is incident on the hypotenuse side of the right-angle prism, it experiences a 90-degree TIR when it hits the glass/air interface at the leg the first time, and then it encounters another 90° TIR when it hits the glass/air interface at the leg the second time, contributing to a 180° light redirection in total. The right-angle prism, now becoming a 180° retroflector, could be leveraged as a non-reversing mirror in binoculars, and the 180-degree deviation of the light path is not reliant on the angle at which the light enters the hypotenuse.

Right-angle prisms exhibit certain advantages when compared with other optical counterparts with similar functions. it's a great deal simpler to mount and bend from the outside than inclined mirrors in the concern of mechanical design, as well as in situations with high acoustic or inertial loads. Furthermore, the right-angle prisms can be utilized as a retroreflector, redirecting beams back in the direction that came from, as long as the acceptance angle constraints for TIR from the roof faces are not exceeded.

This page highlights Shanghai North Optics's Off-the-shelf Right-Angle Prisms. Two substrate materials are available: N-BK7 or UV Fused Silica. The Dimensions are diversified, the lengths of the legs range from 3-60mm, while the length of the hypotenuse ranges from 4.24-84.85mm. Besides, these stocked right-angle prisms feature high precision with the surface flatness bridled tight to λ/10 @632.8nm. At the current time, the standard prisms in our storage are uncoated, however, you might also request custom coating options and learn the relevant details in our Custom Right Angle Prism catalog. 

North Optics is an industrial-leading team with professional knowledge in the domain of optics and lasers, through stringent control of qualities and tolerances, and high-precision polishing techniques, North Optics's right angle prisms present minimized wavefront distortion, scattering, and other undesirable diffraction effects.

Application Notes:

1.  Figure 1 shows the light path undergoes a 90-degree deviation when it projects on the hypotenuse.