Knight Optical’s Precision right-angle prisms (BK7 or equivalent)

04 Mar 2018

Right angle prisms are simply triangular blocks of glass with two 45° & one 90° angles. The precision grade right angle prisms have high surface quality and tight tolerance angles.

The normal use for a right-angle prism is to turn light through 90° by internal reflection from the hypotenuse. These right-angle prisms are stocked with a variety of coatings to meet a variety of applications, we are also able to supply custom RAPs to your specifications.

The simplest is a totally uncoated right-angle prism; uncoated right-angle prisms will rely on total internal reflection and so is limited in the angular range it will reflect. Prisms coated with a standard reflecting coating, generally aluminum, will work over a wider range of incidence angles.

These are commonly known as protected right-angle prisms. Another option is to apply a conventional mirror coating on the hypotenuse surface, which allows the prism to be used as a mirror but mounted from behind, these types of prism are commonly known as external reflector prisms. We also supply a stock & custom range of extended broad band anti-reflective right angle prisms coated on the input and output faces to improve efficiency. Right angle prisms are generally used to bend light, reflect light and for image displacement.

Stock right angled prisms are available to purchase directly from our website . We also offer custom right angled prisms in unique sizes and designs to meet our customers individual requirements. For more information on our custom capabilities or to place an order, please contact our technical sales team.

Options listed here for right angle prisms:

Uncoated range: All faces are left uncoated.
AR coated range: Antireflective coating on entry/exit faces to achieve 99% efficiency.
Protected range: Aluminized and black painted on Hypotenuse to achieve 90% internal reflection over a greater angular range.
External reflector range: Aluminized and protected on hypotenuse for use as mirrors.
Uncoated prisms can be coated with a range of mirror coatings for UV,NIR and FIR applications.
Prisms can be ground down on width to smaller dimensions.
Prisms can be reshaped to meet your instrument needs.

Material:	N-BK7 or equivalent
Dimensions:	+0.0/-0.2mm
Angles:	±1 arcmin
Surface quality:
Flatness:	<λ/4 over 25mm (over inscribed eclipse)

Coating
AR coated range:
Antireflective coated/ extended visible (AV2)
Broadband Multilayer AR, R.avg<0.5%@450-950nm, AOI= 0°-45 °
Protected range:
Protected aluminium/ visible use (MV2) Ali/SiO₂ R.avg.>88%@450-650nm,AOI=0°-45°
Protection is matt black paint however surfaces on custom prisms can be coated with epoxy matt black paint, see drawings
External reflector range:
Protected aluminium/ visible use (MV2)
Ali/SiO₂ R.avg.>88%@450-650nm,AOI=0°-45°

All our Prisms are fully inspected on their quality in our ISO 9001:2015 certified, state-of-the-art Metrology laboratory. This allows us to work to the highest QA standards and meet the tolerance specifications on these precision components.

Contact our technical sales team to discover how Knight Optical’s high quality Right Angle Prisms and superior service can improve your instrumentation and supply chain experience.