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Mounted Dove Prisms


  • Rotate, Invert, or Retroreflect an Image
  • Six Different Sizes Available
  • Available Uncoated or AR Coated for 350 - 700 nm or 650 - 1050 nm

PS991M

10 mm Wide Prism,
SM1-Threaded Mount

PS992M-A

15 mm Wide AR-Coated Prism,
SM1-Threaded Mount

PS990M

5 mm Wide Prism,
SM05-Threaded Mount

KS1RS Kinematic Rotation Mount
Allows 360º Rotation Control of
PS992M Mounted Dove Prism

Application Idea

Related Items


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Common Specificationsa
Material N-BK7b
Clear Aperture >70% of Max Face Length
and Width
Surface Quality of Polished Surfaces 40-20 Scratch-Dig
Surface Flatness λ/5 at 632.8 nm
  • See the Specs tab for more information.
  • Click Link for Detailed Specifications on the Substrate Glass
Dove Prism Drawing
Click to Enlarge

Dove Prism Cross-Sectional View (Left) and Side View (Right)
(See Specs Tab for Details)
Dove Prism in Slotted Lens Tube
Click to Enlarge

Mounted Dove Prism Inside a Slotted Lens Tube with Spanner Wrench
(All Sold Separately)

This animation shows how the image rotates as the prism is rotated.
Optical Coatings and Substrates
Optic Cleaning Tutorial

Features

  • Rotate and Invert an Image or Retroreflect Light
  • Mounted Prisms Compatible with our Threaded Rotation Mounts
  • Offered Uncoated in Six Sizes (See Diagram to the Right)
    • A = 5 mm, SM05-Threaded Mount
    • A = 10 mm, SM1-Threaded Mount
    • A = 15 mm, SM1-Threaded Mount
    • A = 20 mm, SM2-Threaded Mount
    • A = 25 mm, SM2-Threaded Mount
    • A = 30 mm, SM2-Threaded Mount
  • 15 mm Size Also Available with One of Two AR Coatings
    • 350 - 700 nm
    • 650 - 1050 nm

A Dove prism is used to rotate, invert, or retroreflect an image, depending upon the prism's rotation angle and the surface through which the light enters the prism. Thorlabs' mounted Dove prisms are fabricated from N-BK7 glass for high transmission from the visible to the near-infrared spectral range. Prisms of different sizes are available mounted inside externally SM05-threaded (0.535"-40), SM1-threaded (1.035"-40), or SM2-threaded (2.035"-40) housings. When combined with any of our selection of SM05, SM1, or SM2 rotation mounts, these housings allow an image incident on the angled face of the prism to be continuously rotated through a full 360°. The longest face is also left exposed, allowing the mounted prism to retroreflect light. Each prism has a square cross section. Our 15 mm mounted Dove prism is available either uncoated or with one of two AR coatings deposited on the two angled faces (see the Specs tab for more information on dimensions and AR coatings). We also offer these Dove prisms unmounted. For information on our full selection of prisms, please see the Prism Guide tab.

The anodized aluminum housings contain two slots designed to accept our SPW801 Adjustable Spanner Wrench. These slots enable the prism to be threaded into one of our Ø1/2", Ø1", or Ø2" Lens Tubes. The SPW908 and SPW909 Spanner Wrenches may also be used with SM05- and SM1-threaded mounted prisms, respectively. Shown to the right is a PS992M inserted into an SM1L30C Slotted Lens Tube. The SM1RR Retaining Ring included with the lens tube secures the mounted prism.

Dove prisms can be thought of as right-angle prisms with the triangular apex removed, which reduces the weight of the prism and stray internal reflections. They introduce astigmatism when used with converging light, so we recommend using them with collimated light. Additionally, these prisms affect the polarization state of light transmitted through them. See the Lab Facts tab for further details.

Image Rotation
Light is usually propagated along the longitudinal axis of a Dove prism. In this geometry, shown in the diagrams on the bottom left and middle, light reflects once from the bottom face, inverting the image on the other side. Rotation of the prism about the longitudinal axis rotates the image at twice the rate of the prism's rotation (see video to the right). For example, a 20° rotation of the prism results in a 40° rotated image. The AR-coated Dove prisms are designed specifically for the image rotation and inversion application.

Due to the high incidence angle, the light reflecting from the bottom face undergoes total internal reflection, even if the light's propagation axis and the prism's longitudinal axis are not exactly parallel. Hence, in a Dove prism, the magnitude of the internal transmission is limited only by absorption.

Retroreflection
When light is incident on the longest face, the Dove prism acts as a retroreflector or a right-angle prism. The light exits parallel to the input light (independent of the incidence angle) and is inverted by 180°. This geometry is shown below and to the right. In situations with limited space or where more convenient mounting options are needed, the Dove prism can replace a retroreflector or right-angle prism.

Custom Coatings
Upon request, our uncoated prisms can be AR coated for the 290 - 370 nm (-UV), 350 - 700 nm (-A), 650 - 1050 nm (-B), or 1050 - 1700 nm (-C) spectral ranges. Please contact Technical Support for more information.

Dove Prism Drawing
Light propagated along the longitudinal axis is inverted by 180°.
Dove Prism Drawing
Rotation of the prism over some angle results
in a rotation of the image over twice that angle.
1
Light incident on the longest face of the prism is retroreflected and inverted by 180°.
Unmounted Prism DimensionsaHousing Specificationsa
Item # Prefix A B LPb D LH Threading
PS990M 5 mm 7.1 mm 21.1 mm Ø5 mm 26.3 mm SM05 (0.535"-40)
PS991M 10 mm 14.1 mm 42.2 mm Ø10 mm 49.9 mm SM1 (1.035"-40)
PS992M 15 mm 21.2 mm 63.4 mm Ø15 mm 70.6 mm
PS994M 20 mm 28.3 mm 84.5 mm Ø20 mm 94.8 mm SM2 (2.035"-40)
PS995M 25 mm 35.4 mm 105.7 mm Ø25 mm 115.9 mm
PS993M 30 mm 42.4 mm 126.3 mm Ø30 mm 136.5 mm
  • Refer to the Diagram Below
  • Unbeveled Length
General Specifications
Material N-BK7a
Clear Aperture >70% of Max Face Length
and Widthb
Surface Quality of Polished Surfaces 40-20 Scratch-Dig
Surface Flatness λ/5 at 632.8 nm
Optically Polished Surfacesb S1, S2, and S3
Fine Ground Surfacesb All Surfaces Except
S1, S2, and S3
Dimensional Tolerance ±0.15 mm
Angular Tolerance ±3 arcmin
  • Click Link for Detailed Specifications on the Substrate Glass
  • Refer to the Diagram Below and to the Right
Mounted Dove Prism Drawing
Click to Enlarge

Cross-Sectional View (Left) and Side View (Right)
of Unmounted Dove Prism and Housing
AR Coating Specifications
Item # PS992M-A PS992M-B
Wavelength Range (Click for Plot) 350 - 700 nm 650 - 1050 nm
Reflectance Over AR Coating Range
(Avg., AOI = 45° with Respect to
the Coated Surface)
<1%
AR-Coated Surfacesa S1 and S2
  • Refer to the Diagram to the Right

The transmission curve for N-BK7, a RoHS-compliant form of BK7, is shown below. The data was obtained for a 10 mm thick, uncoated sample and includes surface reflections. For an excel file of the data, please click the link below the graph.

N-BK7 Transmission Curve
Click to Enlarge

Click Here for Raw Data

The graphs below give the measured reflectance of AR-coated Dove prisms at a 45° AOI with respect to the coated surface. The graph on the left corresponds to the PS992M-A Dove prism, while the graph on the right corresponds to the PS992M-B Dove prism. For Excel files of the reflectance data, please click the links below the graphs.

A-Coated Reflectance
Click to Enlarge

Click Here for Raw Data
Please note that this is measured reflectance data. The shaded region indicates the range over which we guarantee the average reflectance will be <1% for a 45° AOI.
B-Coated Reflectance
Click to Enlarge

Click Here for Raw Data
Please note that this is measured reflectance data. The shaded region indicates the range over which we guarantee the average reflectance will be <1% for a 45° AOI.

Thorlabs Lab Fact: Dove Prisms Alter Polarization State and Image Orientation

We present laboratory measurements of the polarization and rotation state of a beam transmitted through Thorlabs’ PS992 and PS992M Dove Prisms. We also examine the influence of stress-induced birefringence on the final polarization state. In a polarization-dependent experiment, it is important to understand how the polarization and orientation of the input beam is altered by a Dove prism. While it is known that Dove prisms introduce changes in the polarization of the transmitted light [1], we also find that localized stress-induced birefringence can significantly alter the polarization state. Finally we compare theoretical predictions of induced polarization change to the measured polarization change for both our unmounted and mounted versions of Dove prism.

For our experiment we used the HL6320G Laser Diode (635 nm) as the light source. The laser beam was initially aligned using two crossed Glan-Taylor polarizers (GT10-A). The first polarizer set the polarization axis, and the rotation angle of the second crossed polarizer was recorded. The Dove prism was then placed in between the two polarizers, and the power of the beam was recorded after the second polarizer as a function of prism angle. Additionally, measurements were taken to determine the radii and orientation angle of the polarization ellipse. The polarization shift caused by the PS992 unmounted Dove prism and PS992M mounted Dove prism were measured. The unmounted prism was tested for polarization changes due to birefringence effects as well.

Lab Facts Complete Summary

The figure to the top right summarizes the measured results for image orientation as a function of prism angle. While it is well known that Dove prisms are used to invert images, it is interesting to note that the image rotation angle is twice that of the prism rotation angle. The figure to the bottom left summarizes the results of stress-induced birefringence on polarization state, while the figure to the bottom right summarizes the effects a Dove prism has on the polarization state and compares that to the theoretical values. Data is presented for both the unmounted and mounted Dove prisms with minimal stress. While Dove prisms do rotate the image, the polarization does not rotate with the image. Rather, the polarization is transformed from linear to various degrees of elliptical. For details on the experimental setup employed and the results summarized here, please click here.

[1] Miles J. Padgett & J. Paul Lesso, "Dove prisms and polarized light," J. Mod. Opt. 46, 175-179 (1999).

Selection Guide for Prisms

Thorlabs offers a wide variety of prisms, which can be used to reflect, invert, rotate, disperse, steer, and collimate light. For prisms and substrates not listed below, please contact Tech Support.

Beam Steering Prisms

Prism Material Deviation Invert Reverse or Rotate Illustration Applications
Right Angle Prisms N-BK7, UV Fused Silica, Calcium Fluoride, or Zinc Selenide 90° 90° No  1

90° reflector used in optical systems such as telescopes and periscopes.

180° 180° No  1

180° reflector, independent of entrance beam angle.

Acts as a non-reversing mirror and can be used in binocular configurations.

Unmounted Retroreflectors
and
Mounted Retroreflectors

N-BK7 180° 180° No  Retroreflector

180° reflector, independent of entrance beam angle.

Beam alignment and beam delivery. Substitute for mirror in applications where orientation is difficult to control.

Unmounted Penta Prisms
and
Mounted Penta Prisms
N-BK7 90° No No  1

90° reflector, without inversion or reversal of the beam profile.

Can be used for alignment and optical tooling.

Roof Prisms N-BK7 90° 90° 180o Rotation  1

90° reflector, inverted and rotated (deflected left to right and top to bottom).

Can be used for alignment and optical tooling.

Unmounted Dove Prisms
and
Mounted Dove Prisms
N-BK7 No 180° 2x Prism Rotation  1

Dove prisms may invert, reverse, or rotate an image based on which face the light is incident on.

Prism in a beam rotator orientation.

180° 180° No  1

Prism acts as a non-reversing mirror.

Same properties as a retroreflector or right angle (180° orientation) prism in an optical setup.

Wedge Prisms N-BK7 Models Available from 2° to 10° No No  1

Beam steering applications.

By rotating one wedged prism, light can be steered to trace the circle defined by 2 times the specified deviation angle.

No No  Wedge Prism Pair

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 Variablea No No  Coupling Prism

High index of refraction substrate used to couple light into films.

Rutile used for nfilm > 1.8

GGG used for nfilm < 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, Calcium Fluoride,
or Zinc Selenide
Variablea No No  

Dispersion prisms are a substitute for diffraction gratings.

Use to separate white light into visible spectrum.

Dispersion Compensating Prism Pairs Fused Silica, Calcium Fluoride, SF10, or N-SF14 Variable Vertical Offset No No  Dispersion-Compensating Prism Pair

Compensate for pulse broadening effects in ultrafast laser systems.

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

 

Pellin Broca Prisms N-BK7,
UV Fused Silica,
or Calcium Fluoride
90° 90° No  1

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.

  • 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 No No  1

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.

Axicons UV Fused Silica Variablea No No  1

Creates a conical, non-diverging beam with a Bessel intensity profile from a collimated source.

  • Depends on Prism Physical Angle

Polarization Altering Prisms

Prism Material Deviation Invert Reverse or Rotate Illustration 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°a
No No  Glan-Taylor Polarizer

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  Rutile Polarizer Diagram

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  Glan-Taylor Polarizer

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  Glan-Thompson Polarizer

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 and
Wollaston Polarizers
Quartz, Magnesium Fluoride, α-BBO, Calcite, Yttrium Orthovanadate Symmetric
p-pol. and
s-pol. deviation angle
No No  Wollaston Prism

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.

Rochon Prisms Magnesium Fluoride
or
Yttrium Orthovanadate
Ordinary Ray: 0°

Extraordinary Ray: deviation angle
No No

Double prism configuration and birefringent MgF2 or YVO4 produce a small deviation angle with a high extinction ratio.

Extraordinary ray deviates from the input beam's optical axis, while ordinary ray does not deviate.

Beam Displacing Prisms Calcite 2.7 or 4.0 mm Beam Displacement No No  Beam Displacing Prism

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 90o separation is not possible.

Fresnel Rhomb Retarders N-BK7 Linear to circular polarization

Vertical Offset
No No  Fresnel Rhomb Quarter Wave

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.

Rotates linearly polarized light 90° No No  Fresnel Rhomb Half Wave

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 Cubes N-BK7 50:50 splitting ratio, 0° and 90°

s- and p- pol. within 10% of each other
No No  Non-polarizing Beamsplitter

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

Non-polarizing beamsplitter over the specified wavelength range.

Polarizing Beamsplitter Cubes N-BK7, UV Fused Silica, or N-SF1 p-pol. - 0°

s-pol. - 90°
No No  Polarizing Beamsplitter Cube

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

For highest polarization use the transmitted beam.


Posted Comments:
voronov.alexander  (posted 2014-02-19 09:37:18.18)
Could you make a mounted Dove prism with UV fused silica and with AR coating on 355nm? I would like to have a few units of prisms. If yes, could you send me a quotation?
jlow  (posted 2014-02-27 02:23:59.0)
Response from Jeremy at Thorlabs: We will contact you directly on quoting this.

Mounted Dove Prisms, Uncoated


Click to Enlarge

Cross-Sectional View (Left) and
Side View (Right) of a Dove Prism
Item #AaLaThreadingb
PS990M 5 mm 21.1 mm SM05 (0.535"-40)
PS991M 10 mm 42.2 mm SM1 (1.035"-40)
PS992M 15 mm 63.4 mm
PS994M 20 mm 84.5 mm SM2 (2.035"-40)
PS995M 25 mm 105.7 mm
PS993M 30 mm 126.3 mm
  • As Specified in the Diagram to the Right
  • Please See the Specs Tab for Housing Details
  • Uncoated N-BK7 for the 350 nm to 2.0 µm Wavelength Range
  • Available in Six Sizes (See Table and Diagram to the Right)
  • Rotate, Invert, or Retroreflect an Image
  • Compatible with SM05-, SM1-, or SM2-Threaded Optomechanics

These mounted, uncoated Dove prisms are offered with square cross sections in six different sizes (please see the table and diagram to the right). As described in the Overview tab above, the two angled faces are typically used together to rotate an image, while the longest face can be used to retroreflect an image. The angled faces and longest face of our Dove prisms are optically polished surfaces. All other surfaces are fine ground and inaccessible due to the mount.

Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
PS990M Support Documentation
PS990MSM05-Mounted Dove Prism, 5 mm, N-BK7, Uncoated
$215.34
Today
PS991M Support Documentation
PS991MSM1-Mounted Dove Prism, 10 mm, N-BK7, Uncoated
$215.34
Today
PS992M Support Documentation
PS992MCustomer Inspired! SM1-Mounted Dove Prism, 15 mm, N-BK7, Uncoated
$215.34
Today
PS994M Support Documentation
PS994MCustomer Inspired! SM2-Mounted Dove Prism, 20 mm, N-BK7, Uncoated
$270.53
Today
PS995M Support Documentation
PS995MCustomer Inspired! SM2-Mounted Dove Prism, 25 mm, N-BK7, Uncoated
$270.53
Today
PS993M Support Documentation
PS993MCustomer Inspired! SM2-Mounted Dove Prism, 30 mm, N-BK7, Uncoated
$325.72
Today

Mounted Dove Prism, AR Coated: 350 - 700 nm

Dove Prism Drawing
Click to Enlarge

Cross-Sectional View (Left) and Side View (Right) of a Dove Prism
  • AR Coated for the 350 nm to 700 nm Wavelength Range
  • Available in One Size: A = 15 mm, L = 63.4 mm (See Diagram to the Right)
  • Rotate or Invert an Image
  • Compatible with SM1-Threaded Optomechanics

This SM1-mounted Dove prism has a 15 mm square cross section and an AR coating for 350 to 700 nm deposited on the two angled faces (shown in the diagram to the right, please see the Specs tab for details). This coating provides an average reflectance of <1% (AOI = 45°) over the specified wavelength range. For a plot of the reflectance versus wavelength, please see the Graphs tab.

As described in the Overview tab above, the two angled faces of a Dove prism are typically used together to rotate an image. With an AR coating on both angled faces, this prism is specifically designed for image inversion and rotation. Please note that the AR coating makes these prisms unsuitable for use as retroreflectors. For retroreflecting applications, please use our uncoated Dove prisms. The angled faces and longest face of this Dove prism are optically polished surfaces. All other surfaces are fine ground and inaccessible due to the mount.

Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
PS992M-A Support Documentation
PS992M-ACustomer Inspired! SM1-Mounted Dove Prism, 15 mm, N-BK7, ARC: 350 - 700 nm
$242.39
Today

Mounted Dove Prism, AR Coated: 650 - 1050 nm

Dove Prism Drawing
Click to Enlarge

Cross-Sectional View (Left) and Side View (Right) of a Dove Prism
  • AR Coated for the 650 nm to 1050 nm Wavelength Range
  • Available in One Size: A = 15 mm, L = 63.4 mm (See Diagram to the Right)
  • Rotate or Invert an Image
  • Compatible with SM1-Threaded Optomechanics

This SM1-mounted Dove prism has a 15 mm square cross section and an AR coating for 650 to 1050 nm deposited on the two angled faces (shown in the diagram to the right, please see the Specs tab for details). This coating provides an average reflectance of <1% (AOI = 45°) over the specified wavelength range. For a plot of the reflectance versus wavelength, please see the Graphs tab. 

As described in the Overview tab above, the two angled faces of a Dove prism are typically used together to rotate an image. With an AR coating on both angled faces, this prism is specifically designed for image inversion and rotation. Please note that the AR coating makes these prisms unsuitable for use as retroreflectors. For retroreflecting applications, please use our uncoated Dove prisms. The angled faces and longest face of this Dove prism are optically polished surfaces. All other surfaces are fine ground and inaccessible due to the mount. 

Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
PS992M-B Support Documentation
PS992M-BCustomer Inspired! SM1-Mounted Dove Prism, 15 mm, N-BK7, ARC: 650 - 1050 nm
$242.39
Today
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