A Right Angle Mirror, also known as a turning mirror, is a mirror prism which reflects incident light at 90°. The hypotenuse of these triangular prisms are coated with an enhanced aluminum, silver, or protected gold coating. These mirrors play a key role in compact optical waveguide devices and high-density integrated optics. They require very little alignment and can easily be mounted in an optical system, and are often used for applications where high performance and precise alignment is key. Right angle mirrors are also useful when you wish to decrease the size of your optical system.
In a typical configuration incident light will enter through a short leg of the prism, be reflected by the metallic coating on the hypotenuse side, and leave the prism through the other short leg. Since these mirrors reflect light at a right angle from the angle of entrance, they be used as external or internal reflectors with a wide angle of incidence.
Our right angle mirrors are manufactured from BK7, Schott optical borosilicate-crown glass, and have an enhanced aluminum, protected silver, or protected gold coating. Enhanced aluminum consists of aluminum with a multilayer dielectric overcoat. This coat is designed to optimize reflectance at at the desired wavelength, and enhanced aluminum typically provides a good reflection in UV, visible and mid-IR wavelength. Protected silver is recommended for use with visible light. Protected gold is the best choice for applications working with the full IR spectrum. Neither protected silver or protected gold coatings are sensitive to angle of incidence or polarization, which makes right angle mirrors with these coatings especially versatile.
The BK7 used in our right angle mirrors has a clear, almost colorless appearance. It exhibits a very high refractive index homogeneity and uniform transmission in the visible range. It performs well in all chemical tests, has an excellent optical quality, and is essentially free of bubbles and inclusions.
Our factory standard dictates a clear aperture of greater than 90% of the length of the optic, and dimension tolerance of +0.0 -0.2mm. Surface quality of our factory standard right angle mirrors is 40-20. The first of these two numbers designates the brightness of the largest allowable scratch; the second number refers to the diameter, in microns, of the largest permissible dig.
Right angle mirrors may be ordered with or without protective bevels. A typical bevel is 0.2mmx45.
Our experienced design team would be happy to work with you as you design your optical system. We can support you every step of the way, from print to prototype to production.