Features

Sizes Ranging from 3 mm to 60 mm
Available Fabricated from N-BK7, UV Fused Silica, CaF₂, ZnSe, or Ge
10 mm and 20 mm N-BK7 Versions Available with an AR Coating on the Hypotenuse or Both Legs

Available in sizes ranging from 3 mm to 60 mm, Thorlabs' high precision Right-Angle Prisms can be used to deviate a light path by 90° or 180°, depending on which surface is used as the input for the light source. Our 10 mm and 20 mm N-BK7 prisms are also available with one of our three standard broadband antireflection coatings (-A: 350-700 nm, -B: 650-1050 nm, -C: 1050-1620 nm) on either their hypotenuse or both legs, thereby reducing surface losses.

Due to total internal reflection (TIR), the image to the upper right demonstrates how the right angle prism can be used as a 90^o reflector. When the input light is incident on one of the prism's legs, it undergoes TIR at the glass/air boundary of the hypotenuse and exits via the other prism leg. This 90^o deviation of the input light makes the right angle prism a suitable alternative for a mirror.

The image to the right shows how the right-angle prism can be used as a 180° retroreflector. When the input light is incident on the face of the hypotenuse, it undergoes total internal reflection (TIR) at the glass/air boundary at the prism legs. It undergoes TIR a second time at the next prism leg and exits the hypotenuse in a path parallel to that of the input beam. Like the retroreflector, the 180^odeviation of the light path is independent of the angle at which the light enters the prism.

Please refer to the Prism Guide tab above for assistance in selecting the appropriate prism for your application. For additional antireflecton coating requests, please contact Tech Support.

General Specifications
Material	N-BK7*	UV Fused Silica	CaF₂	ZnSe	Germanium
Clear Aperture	70%
Surface Quality	40-20 Scratch-Dig			60-40 Scratch-Dig
Surface Flatness @ 633 nm	λ/10		λ/2
Number of Polished Faces	3 (Triangular Faces are Fine Ground)

* For the PS911K, please see the specifications listed above right.

PS911K Specifications
Material	N-BK7
Clear Aperture (Legs)	Entire Face Length And Width Excluding a 1.25 mm Border Along Beveled Edges (No Bevel Between the Two Legs)
Clear Aperture (Hypotenuse)	90% of Face Length and Width
Surface Quality	20-10 Scratch-Dig
Surface Flatness @ 633 nm	λ/8
Number of Polished Faces	3 (Triangular Faces are Fine Ground)

Uncoated Prisms

Item #	Material	A = B (mm)	C (mm)	H (mm)	Angle Tolerance
PS605	UV Fused Silica*	3	4.2	3	±10 arcmin
PS609		5	7.1	5	±3 arcmin
PS610		10	14.1	10	±3 arcmin
PS608		20	28.3	20	±3 arcmin
PS611		25	35.4	25	±3 arcmin
PS612		40	56.6	40	±3 arcmin
PS613		60	84.9	60	±3 arcmin
PS905	N-BK7	3	4.2	3	±10 arcmin
PS909		5	7.1	5	±3 arcmin
PS910		10	14.1	10	±3 arcmin
PS908		20	28.3	20	±3 arcmin
PS911		25	35.4	25	±3 arcmin
PS912		40	56.6	40	±3 arcmin
PS913		60	84.9	60	±3 arcmin
PS703	CaF₂	10	14.1	10	±3 arcmin
PS704	CaF₂	25	35.4	25	±3 arcmin
PS701	ZnSe	10	14.1	10	±10 arcmin
PS702	ZnSe	25	35.4	25	±10 arcmin
PS705	Ge	25	35.4	25	±10 arcmin

*Corning Code 7980 Standard Grade Fused Silica

Coated Prisms

Item #	Material	A = B (mm)	C (mm)	H (mm)	Angle Tolerance	AR Coating
PS910H-A	N-BK7	10	14.1	10	±3 arcmin	350 - 700 nm, Hypotenuse
PS910H-B		10	14.1	10	±3 arcmin	650 - 1050 nm, Hypotenuse
PS910H-C		10	14.1	10	±3 arcmin	1050 - 1620 nm, Hypotenuse
PS910L-A		10	14.1	10	±3 arcmin	350 - 700 nm, Legs
PS910L-B		10	14.1	10	±3 arcmin	650 - 1050 nm, Legs
PS910L-C		10	14.1	10	±3 arcmin	1050 - 1620 nm, Legs
PS908H-A		20	28.3	20	±3 arcmin	350 - 700 nm, Hypotenuse
PS908H-B		20	28.3	20	±3 arcmin	650 - 1050 nm, Hypotenuse
PS908H-C		20	28.3	20	±3 arcmin	1050 - 1620 nm, Hypotenuse
PS908L-A		20	28.3	20	±3 arcmin	350 - 700 nm, Legs
PS908L-B		20	28.3	20	±3 arcmin	650 - 1050 nm, Legs
PS908L-C		20	28.3	20	±3 arcmin	1050 - 1620 nm, Legs

Right Angle Prism Drawing

$UV Fused Silica Index of Refraction$
Click to Enlarge

$N-BK7 Index of Refraction$
Click to Enlarge

$CaF2 Index of Refraction$
Click to Enlarge

$Germanium Index of Refraction$
Click to Enlarge

$CaF2 Index of Refraction$
Click to Enlarge

Click Here to Download Index of Refraction Data

Selection Guide for Prisms

Thorlabs offers a wide variety of prisms, which can be used to reflect, invert, rotate, disperse, steer, and collimate light. Prisms are available in N-BK7, UV Fused Silica, F2, N-SF11, α-BBO, N-KZFS8, Ge, and CaF₂. For prisms and substrates not listed below, please contact tech support.

Beam Steering Prisms

Prism	Material	Deviation	Invert	Reverse or Rotate	Applications
Right Angle Prisms	N-BK7, UV Fused Silica, Germanium, or Calcium Fluoride	90°	90°	No	90° reflector, independent of entrance beam angle. Used in optical systems such as telescopes and periscopes.
Right Angle Prisms	N-BK7, UV Fused Silica, Germanium, or Calcium Fluoride	180°	180°	No	180° reflector, independent of entrance beam angle. Acts as a non-reversing mirror and can be used in binocular configurations.
Retroreflectors and Mounted Retroreflectors	N-BK7	180°	180°	No	180° reflector, independent of entrance beam angle. Beam alignment and beam delivery. Substitute for mirror in applications where orientation is difficult to control.
Penta Prisms and Mounted Penta Prisms	N-BK7	90°	No	No	90° reflector, without inversion or reversal of the beam profile. Can be used for alignment and optical tooling.
Roof Prisms	N-BK7	90°	90°	180^o Rotation	90° reflector, inverted and rotated (deflected left to right and top to bottom). Can be used for alignment and optical tooling.
Dove Prisms and Mounted Dove Prisms	N-BK7	No	180°	2x Prism Rotation	Dove prisms may invert, reverse, or rotate an image based on which face the light is incident on. Prism in a beam rotator orientation.
Dove Prisms and Mounted Dove Prisms	N-BK7	180°	180°	No	Prism acts as a non-reversing mirror. Same properties as a retro-reflector or right angle (180° orientation) prism in an optical setup.
Wedge Prisms	N-BK7	Models Available from 2° to 10°	No	No	Beam steering applications. By rotating one wedged prism, light can be steered to trace the circle defined by 2 times the specified deviation angle.
Wedge Prisms	N-BK7	Models Available from 2° to 10°	No	No	Variable beam steering applications. When both wedges are rotated, the beam can be moved anywhere within the circle defined by 4 times the specified deviation angle.
Coupling Prisms	Rutile (TiO₂) or GGG	Variable*	No	No	High index of refraction substrate used to couple light into films. Rutile used for n_film > 1.8 GGG used for n_film < 1.8

* Depends on angle of incidence and index of refraction

Dispersive Prisms

Prism

Material

Deviation

Invert

Reverse or Rotate

Illustration

Applications

Equilateral Prisms

F2, N-SF11, Germanium, or Calcium Flouride

Variable*

Dispersion prisms are a substitute for diffraction gratings.

Use to separate white light into visible spectrum.

Pellin Broca Prisms

N-BK7, UV Fused Silica, or CaF₂

90°

Ideal for wavelength separation of a beam of light, output at 90°.

Used to separate harmonics of a laser or compensate for group velocity dispersion.

Dispersion Compensating Prism Pairs

Fused Silica, CaF₂, SF10, or N-SF14

Variable Vertical Offset

Compensate for pulse broadening effects in ultrafast laser systems.

Can be used as an optical filter, for wavelength tuning, or dispersion compensation.

* Depends on angle of incidence and index of refraction

Beam Manipulating Prisms

Prism

Material

Deviation

Invert

Reverse or Rotate

Illustration

Applications

Anamorphic Prism Pairs

N-KZFS8 or N-SF11

Variable Vertical Offset

Variable magnification along one axis.

Collimating elliptical beams (e.g., laser diodes)

Converts an elliptical beam into a circular beam by magnifying or contracting the input beam in one axis.

Polarization Altering Prisms

Prism	Material	Deviation	Invert	Reverse or Rotate	Applications
Glan-Taylor, Glan-Laser, and α-BBO Glan-Laser Polarizers	Glan-Taylor: Calcite Glan-Laser: α-BBO or Calcite	p-pol. - 0° s-pol. - 112°*	No	No	Double prism configuration and birefringent calcite produce extremely pure linearly polarized light. Total Internal Reflection of s-pol. at the gap between the prism while p-pol. is transmitted.
Rutile Polarizers	Rutile (TiO₂)	s-pol. - 0° p-pol. absorbed by housing	No	No	Double prism configuration and birefringent rutile (TiO₂) produce extremely pure linearly polarized light. Total Internal Reflection of p-pol. at the gap between the prisms while s-pol. is transmitted.
Double Glan-Taylor Polarizers	Calcite	p-pol. - 0° s-pol. absorbed by housing	No	No	Triple prism configuration and birefringent calcite produce maximum polarized field over a large half angle. Total Internal Reflection of s-pol. at the gap between the prism while p-pol. is transmitted.
Glan Thompson Polarizers	Calcite	p-pol. - 0° s-pol. absorbed by housing	No	No	Double prism configuration and birefringent calcite produce a polarizer with the widest field of view while maintaining a high extinction ratio. Total Internal Reflection of s-pol. at the gap between the prism while p-pol. is transmitted.
Wollaston Prisms Wollaston Polarizers	Calcite	Symmetric p-pol. and s-pol. deviation angle	No	No	Double prism configuration and birefringent calcite produce the widest deviation angle of beam displacing polarizers. s-pol. and p-pol. deviate symmetrically from the prism. Wollaston prisms are used in spectrometers and polarization analyzers.
Beam Displacing Prisms	Calcite	2.7 or 4.0 mm Beam Displacement	No	No	Single prism configuration and birefringent calcite separate an input beam into two orthogonally polarized output beams. s-pol. and p-pol. are displaced by 2.7 or 4.0 mm. Beam displacing prisms can be used as polarizing beamsplitters where 90^o separation is not possible.
Fresnel Rhomb Retarders	N-BK7	Linear to circularly polarization Vertical Offset	No	No	λ/4 Fresnel Rhomb Retarder turns a linear input into circularly polarized output. Uniform λ/4 retardance over a wider wavelength range compared to birefringent wave plates.
Fresnel Rhomb Retarders	N-BK7	Rotates linearly polarized light 90°	No	No	λ/2 Fresnel Rhomb Retarder rotates linearly polarized light 90°. Uniform λ/2 retardance over a wider wavelength range compared to birefringent wave plates.

* s-polarized light is not pure and contains some p-polarized reflections.

Beamsplitter Prisms

Prism

Material

Deviation

Invert

Reverse or Rotate

Illustration

Applications

Beamsplitter Cube
and
Mounted Beamsplitter Cube

N-BK7 - Grade A
400-700 nm
700-1100 nm
1100-1600 nm

50:50 splitting ratio, 0° and 90°

s- and p- pol. within 10% of each other

Double prism configuration and dielectric coating provide 50:50 beamsplitting nearly independent of polarization.

Non-polarizing beamsplitter over the specified wavelength range.

Polarizing Beamsplitter Cube
and
Mounted Polarizing Beamsplitter Cube

SF2
420-680 nm
620-1000 nm
900-1300 nm
1200-1600 nm

p-pol. - 0°

s-pol. - 90°

Double prism configuration and dielectric coating transmit p-pol. light and reflect s-pol. light.

For highest polarization use the transmitted beam.

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Posted Comments:

Poster: jlow

Posted Date: 2012-11-13 16:34:00.0

Response from Jeremy at Thorlabs: If an appropriate prism with the right AR coating is used, then the loss should be <2% (estimated) when used as a 90° reflector.

Poster: cbrideau

Posted Date: 2012-11-13 13:02:08.243

Like scottie, I'd like to know what the estimated losses would be using the prism as a 90-degree reflector for the near UV and violet-blue? (350-450nm)

Poster: scottie730318

Posted Date: 2012-10-28 22:26:55.98

I would like to know if the PS908L-C is used to internally reflect 1060nm laser beams. What is the energy loss? Thank you.

Poster: tcohen

Posted Date: 2012-06-21 13:54:00.0

Response from Tim at Thorlabs: Thank you for your feedback. I have contacted you to discuss your application further. An important point to note for our mirror coatings is that they are not intended for internal reflection.

Poster: shaun.johnstone

Posted Date: 2012-06-21 09:01:44.0

Larger N-BK7 prisms (e.g. the 20-40mm range) with their hypotenuse AR coated, and their legs gold or silver coated, would be useful for making 2D MOTs with retroreflected beams (see e.g. http://dx.doi.org/10.1051/epjap:2006037)

Poster:

Posted Date: 2011-11-23 18:13:06.0

A Response from Tyler at Thorlabs: The PS610 can be used with 213 nm light. Between surface reflections and internal absorption, the transmitted beam will losses will be approximately 12 percent for your laser. We will contact you with the transmission data, including surface reflections, for UV fused silica.

Poster: laser4u

Posted Date: 2011-11-14 04:02:27.0

I would like to know if the PS610 can be used to internally reflect 213nm laser beams. If yes, what is the energy loss? Our laser emits 213nm@2mJ/pulse@50Hz, beam diameter around 5mm. Thank you. Yiannis Theodoulou Laser Physicist Managing Director Laserlabs Ltd Limassol, Cyprus

Poster: Javier

Posted Date: 2010-06-14 13:20:49.0

Response from Javier at Thorlabs to djchen: at this time, we cannot offer custom right cangle prisms that meet your requirements. The angular tolerance for these prisms is specified as +/- 3 arcmin.

Poster: djchen

Posted Date: 2010-06-14 10:45:56.0

Is it possible to customize right angle prisms? My specifications are: 90 degree deviation < 2arcsec. Pyramidal error between the hypotenuse face and the corresponding edge < 2arcsec. Thank you.

Poster: apalmentieri

Posted Date: 2010-02-18 11:24:25.0

A response from Adam at Thorlabs to jcmgebh: The 90 degree edge has a chamfered edge: 0.2 mm X 0.2 mm. Therefore, this edge is not sharp and should not hurt people.

Poster: jcmgebh

Posted Date: 2010-02-18 10:41:12.0

I wanted to know how sharp the 90 degree edge is. Or is it blunt in order not to hurt people? Sincerely, Christof Gebhardt

Poster: apalmentieri

Posted Date: 2010-01-06 14:55:47.0

A response from Adam at Thorlabs to Yuri: It is possible to get a V coating for 308nm on the PS611. The specifications of our V-coatings are %R< .25% for AOI of 0 degrees. I will email you directly to get more information about the coating you are looking for.

Poster: yuri.kudryavtsev

Posted Date: 2010-01-06 11:59:42.0

Is it possible to have UV (308nm)AR coating on PS611?

Poster: apalmentieri

Posted Date: 2009-07-15 17:39:25.0

A response from Adam at Thorlabs: We currently do not offer the prism you reference as a standard stock item, but we may be able to cut our stock items down to size. I will check with our optics division and let you know via email.

Poster: funrunner13

Posted Date: 2009-07-14 19:22:51.0

Hi, Im looking for a right angled prism where the lengths of the legs (A and B) are not equal to the length of side h. I would like A=B=10 mm and h = 20 mm. Do you offer this? Thank you for your consideration, Leo Montilla

Poster: Laurie

Posted Date: 2009-05-06 14:07:00.0

Response from Laurie at Thorlabs to rene.schneider: We can provide our 5 mm prisms with AR-coated legs. Someone from our technical support staff will get in contact with you shortly to find out which AR coating you need (-A, -B, or -C) and the quantity that you require. Thanks for your interest in our right-angle prisms.

Poster: rene.schneider

Posted Date: 2009-05-06 11:49:54.0

Hello, im looking for a right angeled prism (UV fused silica) with AR-coated legs and a size of 5mm. Do you offer prisms with these specifications? Kind regards, Rene Schneider

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