Opto Sigma

Dove prisms have the useful property that they completely invert an image by 180 degrees. If the prism is rotated about its axis the image will rotate at twice the rate of rotation of the prism. Dove prisms provide the most convenient and most precise method of rotating a beam and their long length and square profile make them easy to mount in a cylindrical sleeve.

Because of the very limited field of view dove prisms need to be used with collimated or near-collimated beams.

These prisms are offered with a broadband multilayer anti-reflective coating on the end faces. The hypotenuse face acts as a TIR surface and is therefore normally not coated. It is important, therefore, to keep this surface clean.

Equilateral prisms are normally used for the dispersion of light into its different colors. Light incident at an oblique angle to the first face is dispersed according to its wavelength and emerges as a spectrum from the opposite face. We offer these prisms made from BK7 optical glass.

Hollow Retro-reflectors consists of three flat mirrors assembled to reflect the input beam by 180 degrees. Unlike the solid corner cubes, the entire optical path is in air and as a result can be used as a broadband reflector. Additionally, because the hollow retro-reflector is configured with only front surface mirrors, the design reduces the affects of polarization and chromatic aberration. The precision assemble of the flat mirrors in the hollow retro-reflectors insure highly accurate beam deviation. Each retro-reflector is assembled in a black anodized aluminum mount. These “angle insensitive” mirrors have numerous uses in alignment and metrology. Our retroreflectors come standard with protective aluminum for use in the visible spectral region.

Penta prisms deviate an input beam by 270 degree (-90 degree) independently of the angle of incidence on the first surface. They are therefore useful as precise right angle mirrors which are insensitive to alignment.

These penta prisms find many metrological applications. These penta prisms are Anti-Reflection coated on the entrance and exit faces as well as being coated with protected aluminum and black paint on the internal reflection faces.

• Laser quality beam steering wedges
• Beam deviation from 1 to 10 degrees
• Can be used in pairs for continuous angular adjustment

  These wedge prisms are intended for steering laser beams. A beam normally incident on the perpendicular surface of the wedge will be deviated according to the anglein the table below. By selecting the appropriate wedge it is simple to create a precise beam deviation without affecting other beam parameters. If two wedges are used together with the sloping surfaces in close proximity it is possible to produce a continuous variation of beam deviation by counter-rotating the wedges. The angular adjustment obtainable in this way ranges from zero to 2 times the angle in the table. The prisms are manufactured from grade A optical glass. These wedge prisms are offered uncoated or with optional Anti-Reflection coatings.   

Retro-reflectors, or corner cubes as they are sometimes called, have the property that light incident on the face of the prism is deviated by 180 degrees independently of its angle of incidence. This means that any light incident on the surface will be reflected back along the same path that it came from.

These retro-reflectors are extremely precise providing an exact 180 degree deviation within a 2arcsec tolerances. This enables them to be used for high precision applications or with lasers over very long distances. These “angle insensitive” mirrors have numerous uses in alignment and metrology. Our retro-reflectors come standard with a broadband AR coating on the face. Optional black paint protected silver may be specified for the legs.

We offer these prisms uncoated or with five different coating options, namely:

• Broadband Multilayer Anti-Reflection coating on legs
• Protected Aluminum on hypotenuse and Broadband Multilayer Anti-Reflection on legs
• Protected Aluminum on hypotenuse
• Protected Aluminum on legs
• Broadband Multilayer Anti-Reflection coating on hypotenuse

These are some of the most versatile prisms available. They can be used as internal or external reflectors or as retro-reflectors according to the orientation of the prism with respect to the incoming light. An uncoated prism will act as a mirror for light incident on one of the short sides (legs) since incident light Is totally internally reflected at the hypotenuse. (TIR occurs when the angle of incidence is greater than the critical angle which for the glass-air interface occurs at 41.2 degrees). Even though uncoated prisms work well their useful full field of view is limited to 10 or 12 degrees in the visible. It is recommended that appropriate coatings be added to optimize the range of prism uses. The Broadband Multilayer Anti-Reflection coating will withstand high power laser use, while the Protected Aluminum coating is evaporated aluminum overcoated with a layer of MgF2 to protect it from scratches and abrasions.