Right-angle prisms (BK7) These Right Angle Prisms are typically used for turning a beam by 90º. Uncoated Right-angle Prisms give total internal reflection of up to 100%, up to a critical angle, corresponding to 5.7º externally for BK7 (@587nm) Right-angle Prisms can also be used as an internal or front surface mirror when the hypotenuse is mirror coated, however it is important that it is kept clean. These Right-angle Prisms are available in two grades, either as Precision or Standard grade. The precision grade has flatter faces with more accurate angles. The AR Coated range achieving 99% overall efficiency with multilayer coatings for 450-900nm on entry and exit faces. The Protected range have the hypotenuse aluminised and black painted for protection (R=85% typically). The External range have the hypotenuse coated with protected aluminised for use as mirrors.

Knight Optical > Prisms > Right-angle prisms (BK7) - Precision Grade Uncoated This is the section containing Uncoated. BBAR coated/ entry + exit faces This is the section containing BBAR coated/ entry + exit faces. Aluminium coated+protected/ Hypotenuse This is the section containing Aluminium coated+protected/ Hypotenuse. External reflector/ Aluminium coated on hypotenuse This is the section containing External reflector/ Aluminium coated on hypotenuse. Only UK and EU customers are charged VAT at 17.5%, customers outside the EU and EU customers based outside the UK who have a valid EU VAT number will not be charged VAT Bulk Discounts! Where (B) appears next to a price below, bulk prices are available, click the (B) button to view! Knight Optical > Prisms > Right-angle prisms (BK7) - Precision Grade

Specification for precision grade Material: BK7 Material data: (see materials section) Dimensions: ±0.1mm Angles: ±1 arcmin Surface quality: <40:20 Flatness: <λ/4 over 25mm (over inscribed eclipse) Coating:   Protected type: Protected aluminium / Visible use (see MV02 coating spec) External type: Protected aluminium / Visible use (see MV02 coating spec) AR coated type: Extended broadband multilayer AR / visible & IR use (see AR06 coating spec)

Note Squares & Rectangles have clean cut and chamfered edges. Diameters have fine ground and chamfered edges Specific requirements We can manufacture Right angle prisms to any size at short notice so if your requirements are not listed please contact us by telephone / fax or email: stockrequirement@knightoptical.co.uk Options available   · Thickness dimension can be machined to a smaller size at sort notice. See also Porro prisms (inverting prisms section)