45° Mounting Adapter for Ø1" or Ø25 mm Polaris® Mirror Mounts

  • Stably Mount Polaris Mirror Mounts at a Fixed 45°
  • Heat Treating Minimizes Temperature-Dependent Hysteresis
  • Ø2 mm Alignment Pinholes for Precision Mounting


45° Adapter

Application Idea

POLARIS-K1F with POLARIS-LN1 Lock Nuts Mounted on a POLARIS-MA45 Mounting Adapter


Related Items

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Each Polaris product undergoes extensive thermal testing to ensure high-quality performance. Please see the Test Data tab for additional test results.

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View Imperial Product List
Item #QtyDescription
Imperial Product List
POLARIS-K1F1Polaris® Low Distortion Ø1" Mirror Mount, 3 Adjusters
POLARIS-MA45145° Mounting Adapter for Ø1" and Ø25 mm Polaris Mounts, 8-32 and 1/4"-20 Taps
POLARIS-CA11Flexure Clamping Arm for Ø1" Posts, Non-Bridging, Stainless Steel, 1.30" Counterbored Slot, 1/4"-20 Clamping Screw
PLS-P11Ø1" Post for Polaris Mirror Mounts, One 8-32 Mounting Hole, L = 1.00"
SS25S05011/4"-20 Stainless Steel Setscrew, 1/2" Long, 25 Pack
POLARIS-LN131/4"-100 Lock Nut, 13 mm Hex, Stainless Steel
View Metric Product List
Item #QtyDescription
Metric Product List
POLARIS-K1F1Polaris® Low Distortion Ø1" Mirror Mount, 3 Adjusters
POLARIS-MA45/M145° Mounting Adapter for Ø1" and Ø25 mm Polaris Mounts, M4 and M6 Taps
POLARIS-CA25/M1Flexure Clamping Arm for Ø25 mm Posts, Non-Bridging, Stainless Steel, 33.0 mm Counterbored Slot, M6 Clamping Screw
PLS-P246/M1Ø25.0 mm Post for Polaris Mirror Mounts, One M4 Mounting Hole, L = 24.6 mm
SS6MS121M6 x 1.0 Stainless Steel Setscrew, 12 mm Long, 25 Pack
POLARIS-LN131/4"-100 Lock Nut, 13 mm Hex, Stainless Steel
A POLARIS-K1F Mirror Mount Held at 45° by a POLARIS-MA45 Mounted on a Ø1" Polaris Post which is Held by a POLARIS-CA1 Clamping Arm


  • Designed for Use With All Ø1" or Ø25 mm Polaris Mirror Mounts
  • Vacuum Compatible to 10-9 Torr at 25 °C with Proper Bake Out
  • Bottom-Located 1/4"-20 (M6) Tap Allows for Attachment to Ø1" Polaris Posts
  • Two Ø2 mm Alignment Pin Holes in the Base for Precision Mounting in OEM Systems
  • Heat-Treated 303 Stainless Steel

The POLARIS-MA45(/M) 45° Mounting Adapters securely mount Ø1" or Ø25 mm Polaris Mirror Mounts at a 45° angle with respect to the optical tablebreadboard, or working surface. The adapter has an 8-32 (M4) tap on the 45° face for securing the mirror mount, and a bottom-located 1/4"-20 (M6) tap for attachment to Ø1" Posts for Polaris Mounts. Two Ø2 mm alignment dowel pin holes around each tap are compatible directly with Ø1" posts for Polaris mounts, and allow for direct, precision mounting within custom or OEM systems (see diagram below for details).

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POLARIS-MA45(/M) Mechanical Drawing

When using our standard Ø1" or Ø25 mm Polaris mounts, the height to the center of the mirror will be 2" from the base of the mounting adapter when using the POLARIS-MA45, or 50 mm if using the POLARIS-MA45/M. The optic center will also be aligned over the center axis of the mount. Please note that when using other Polaris mounts, such as our low-distortion or SM-threaded versions, these values will differ and the mirror center will not be perfectly centered over the center axis of the mount.

This adapter is made from heat-treated 303 stainless steel, which has a relatively low coefficient of thermal expansion (CTE) amd matches the material used in all of our Polaris mirror mounts. Matching the CTE of materials within an optical setup is essential to achieve optimal thermal repeatability. Heat treating the materials used removes the internal stresses that can cause temperature-dependent hysteresis. Therefore, when mounting, we only recommend using components fabricated from the same material. This is shown in the image above, where a POLARIS-K1F mirror mount, POLARIS-MA45 adapter, RS1 Ø1" post, and POLARIS-CA1 clamping arm are used together to mount a mirror at 45° with respect to the mounting surface.

Cleanroom and Vacuum Compatibility
The POLARIS-MA45(/M) is designed to be compatible with cleanroom and vacuum applications. They are chemically cleaned using the Carpenter AAA passivation method to remove sulfur, iron, and contaminants from the surface. After passivation, they are assembled in a clean environment and double vacuum bagged to eliminate contamination when transported into a cleanroom. Please contact Tech Support for details.

POLARIS-MA45 Positional Repeatability After Thermal Shock

Polaris® components have undergone extensive testing to ensure high-quality performance. Here, a Polaris mirror mount was secured to a POLARIS-MA45 which was then secured to a stainless steel rigid platform in a temperature-controlled environment. A beam from an independently temperature-stabilized laser diode was reflected by the mirror onto a position sensing detector.

Purpose: This testing was done to determine how reliably the mirror mount and 45° mounting adapter system returns the mirror, without hysteresis, to its initial position. These measurements show that the alignment of the optical system is unaffected by the temperature shock.

Procedure: The temperature of the Polaris mount and adapter system tested was raised to 37.5 °C. This temperature shock was maintained for approximately 60 minutes (soak time, see plots below). Then the temperature of the mirror mount system was returned to the starting temperature. The results of these tests are shown below.

Results: As can be seen in the plots below, when the Polaris mount and adapter system were returned to their initial temperature, the angular position (both pitch and yaw) of the mirrors returned to within 2 µrad of its initial position. The performance of the Polaris system was tested further by subjecting the mount to repeated temperature change cycles. After each cycle, the mirror mount system position reliably returned to within 2 µrad of its initial position.

Conclusions: The Polaris 45° mounting adapter paired with a Polaris mirror mount is a high-quality, ultra-stable system that will reliably return a mirror to its original position after cycling through a temperature change. As a result, this system is ideal for use in applications that require long-term alignment stability. This also shows that the addition of the POLARIS-MA45 to the Polaris mirror mount does not compromise the performance of the mirror mount alone.

POLARIS-19S50 Thermal Data
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The plot above shows the pitch and yaw measured by a position-sensing detector before, while, and after a thermal shock was applied to the POLARIS-MA45 mounting adapter and Polaris mirror mount.
Polaris-19S50 Thermal Shock Tests
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The plot above shows the final angular position of the system for 10 consecutive thermal shock tests. The change in temperature is the difference between the starting temperature and the temperature at the end of the test and includes factors such as the variation in room temperature.

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Polaris Mount Optic Retention Methods (Click Image to Enlarge)
Side Lock SM Threaded Low Distortion Glue In
Polaris Mount Adjuster Types (Click Image for Details)
Side Hole Hex Adjuster Knobs Adjuster
Lock Nuts
Piezo Adjusters Vertical-Drive Adjusters

Thorlabs offers several different general varieties of Polaris mounts, including kinematic side optic retention, SM-threaded, low optic distortion, piezo-actuated, vertical drive, and glue-in optic mounts, as well as a fixed monolithic mirror mount and fixed optic mounts. Click to expand the tables below and see our complete line of Polaris mounts, listed by optic bore size, and then arranged by optic retention method and adjuster type. We also offer a line of accessories that have been specifically designed for use with our Polaris mounts; these are listed in the table immediately below.

If your application requires a mirror mount design that is not available below, please contact Tech Support.
Polaris Mounts for Ø1/2" Optics

Polaris Mounts for Ø19 mm (3/4") Optics

Polaris Mounts for Ø25 mm Optics

Polaris Mounts for Ø1" Optics

Polaris Mounts for Ø1.5" Optics

Polaris Mounts for Ø50 mm Optics

Polaris Mounts for Ø2" Optics

Polaris Mounts for Ø3" Optics

Polaris Mounts for Ø4" Optics

Polaris Mounts for Ø6" Optics

Polaris Kinematic Platform Mount
Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Imperial Price Available
POLARIS-MA45 Support Documentation
POLARIS-MA45Customer Inspired! 45° Mounting Adapter for Ø1" and Ø25 mm Polaris Mounts, 8-32 and 1/4"-20 Taps
+1 Qty Docs Part Number - Metric Price Available
POLARIS-MA45/M Support Documentation
POLARIS-MA45/MCustomer Inspired! 45° Mounting Adapter for Ø1" and Ø25 mm Polaris Mounts, M4 and M6 Taps