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Polaris® Low Drift Kinematic Platform Mount
Polaris Platform Mount Shown with Stainless Steel Clamping Arm to Mount 1" Cube Beamsplitter
Kinematic Platform Mount
Matched Actuator and Body Pairs
8-32 (M4) Mounting Taps
Sapphire Seats on All Adjusters
Heat-Treated Stainless Steel
Mounts for OEMsThorlabs' Polaris Platform Mount was designed to meet the needs of OEM customers. To that end, we are equipped to manufacture these mounts in high volumes and with timed delivery. Additionally, we can design and manufacture modified versions of these mounts that have different tapped mounting holes, clearance holes or platform sizes. For example, we have produced similar platform mounts with a 2" x 2" platform size and a different 8-32 hole pattern. To find out more about our OEM capabilities, please contact Tech Support.
The Polaris® Kinematic Platform Mount is the ultimate solution for applications requiring stringent long-term alignment stability. The platform surface features an array of nine 8-32 (M4) tapped holes and one #8 (M4) clearance hole for mounting optomechanical components. Alignment pin holes, located on either side of the clearance hole and two of the taps, allow for precise alignment of components mounted to the surface of the platform.
Cleanroom and Vacuum Compatibility
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POLARIS-K1M4 Top Plate
Polaris® Kinematic Mounts Test Data
The Polaris Platform Mounts have undergone extensive testing to ensure high-quality performance. A POLARIS-B1G fixed mount with a mirror glued in was attached to the POLARIS-K1M4 platform mount. This assembly was then mounted to a Ø1" stainless steel post, and then secured to a stainless steel optical table in a temperature-controlled environment. A beam from an independently temperature-stabilized laser diode was reflected by the mirror onto a position sensing detector.
Positional Repeatability After Thermal Shock
Purpose: This testing was done to determine how reliably the mount returns the optic, 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 each mount tested was raised to 37.5 °C and maintained for a given soak time. Then the temperature of the mirror mount 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 mounts were returned to their initial temperature, the angular position (both pitch and yaw) of the optics returned to within 2 µrad of its initial position. The performance of the Polaris was tested further by subjecting the mount to repeated temperature change cycles. After each cycle, the mirror’s position reliably returned to within 2 µrad of its initial position.
For Comparison: To get a 1 µrad change in the mount’s position, the 100 TPI adjuster on the Ø1" Polaris mounts needs to be rotated by only 0.05° (1/7200 of a turn). A highly skilled operator might be able to make an adjustment as small as 0.3° (1/1200 of a turn), which corresponds to 6 µrad.
Conclusions: The Polaris Mirror Mounts are high-quality, ultra-stable mounts that will reliably return a mirror to its original position after cycling through a temperature change. As a result, the Polaris mounts are ideal for use in applications that require long-term alignment stability.
Several common factors typically lead to beam misalignment in an optical setup. These include temperature-induced hysteresis of the optic's position, crosstalk, drift, and backlash. Polaris mounts are designed specifically to minimize these misalignment factors and thus provide extremely stable performance. Hours of extensive research, multiple design efforts using sophisticated design tools such as finite element analysis software, and months of rigorous testing went into choosing the best components to provide an ideal solution for experiments requiring ultra-stable performance from a kinematic mount.
Drift and Backlash
Cleanroom and Vacuum Compatibility
The sapphire contacts are bonded into place using a NASA-approved low outgassing procedure. In addition, DuPont Krytox® LVP High-Vacuum Grease, an ultra-high-vacuum-compatible, low outgassing PTFE grease, is applied to the adjusters. The 8-32 and M4 cap screws included with the Polaris mounts are not rated for pressures below 10-5 Torr.
Through thermal changes and vibrations, the Polaris kinematic mirror mounts are designed to provide years of use. Below are some usage tips to ensure that the mount provides optimal performance.
Use a Wide Post
Front Plate’s Position
Mount as Close to the Table’s Surface as Possible
Lock nut installation demonstrated with the POLARIS-LN1 lock nut on one of our low-distortion Polaris mounts. To install a lock nut without cross threading, gently place the lock nut against the end of the adjuster. "Unscrew" the nut until the threads of the nut and the adjuster align; then thread the nut onto the adjuster.
Polish and Clean the Points of Contact
Adjuster Lock Nuts
To avoid cross threading the POLARIS-LN1 during installation, place it against the adjuster and "unscrew" the lock nut until you feel a slight drop, then thread the lock nut onto the adjuster (see the animation to the right). Each lock nut is pre-greased with the same ultra-high-vacuum-compatible, low-outgassing PTFE grease as the Polaris mounts and has been tested for adjuster fit.
Thorlabs offers several different general varieties of Polaris mounts, including kinematic side optic retention, SM-threaded, low optic distortion, piezo-actuated, 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.
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Methods of Adjusting the Polaris Platform Mount:
A: 5/64" or 2.0 mm Hex Key in the End of the Adjuster
B: 1/16" or 1.5 mm Balldriver Through Adjuster Side Holes
C: HKTS-5/64 Hex Knobs in the Adjuster
D: Hex Knobs with Side Hole Fine Adjustment
The Polaris Kinematic Platform Mount provides a flat mounting surface with high-resolution angular adjustment. The mounting surface features an array of nine 8-32 (M4) tapped holes and one #8 (M4) clearance hole for mounting threaded components. The clearance hole and two of the tapped holes each include two alignment pin holes, which allow the user to precisely align components mounted on these holes using dowel pins. Standard Ø2 mm DIN 7-m6 ground dowel pins are recommended.
The POLARIS-K1M4(/M) includes two removable Ø0.60" adjuster knobs. The adjusters can be driven by a 5/64" (2 mm) hex key or the HKTS-5/64 hex key thumbscrew (sold below), and can be locked using our POLARIS-LN1 Lock Nuts (also sold below). See the image to the right for examples of adjustment methods.
The platform mount can be mounted horizontally on a post using the #8 (M4) counterbore on the back plate of the mount. A clearance hole is provided on the top of the mount for a #8 (M4) cap screw. The platform mount can also be oriented vertically on a post using either of the two #8 (M4) counterbores on the sides of the back plate. Each of these holes for post-mounting includes two alignment pin holes for precise alignment in the larger optical assembly. Standard Ø2 mm DIN 7-m6 ground dowel pins are recommended. We recommend using this mount with a stainless steel post, such as our Ø1" Posts for Polaris Mirror Mounts.
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Click for Details
PM5 Mechanical Drawing
The PM5(/M) Clamping Arm is designed to hold optics on the Polaris kinematic platform mount and Thorlabs' other platform mounts. The arm has an adjustable height and uses a flexure design to secure the optic. The locking screws for both adjusting the height and securing the optic can be tightened or loosened with a 5/64" (2.0 mm) hex key. The post features an 8-32 (M4) threaded stud on the bottom and an 8-32 (M4) internal thread on the top.
The all-stainless-steel design minimizes temperature-dependent hysteresis in environments with large thermal fluctuations, ensuring stable, long-term performance. The clamping arm is chemically cleaned using the Carpenter AAA passivation method to remove sulfur, iron, and contaminants from the surface. Unlike the POLARIS-K1M4(/M) sold above, the clamping arm is not assembled in a clean environment or double vacuum bagged; the user must clean the clamping arm to remove any dust or grease from the surface if it will be used in a clean environment.
These 5/64" Hex Key Adjuster Thumbscrews allow for quick adjustment of many 5/64" and 2 mm hex-driven actuators (or standard actuators with the knobs removed). These temporary knobs can be left in the screw's hex socket between adjustments for convenience (see photo to the right). An 8-32 setscrew (5/64" hex) secures the replaceable hex bit, which can be reversed if the tip is stripped. Contact Tech Support to order replacement hex key bits.
We offer hex key thumbscrews in sizes from 0.050" to 3/16" and 2 mm to 5 mm.
To install a lock nut without cross threading, gently place the lock nut against the end of the adjuster. "Unscrew" the nut until the threads of the nut and the adjuster align before threading the nut onto the adjuster. This animation shows the installation of a POLARIS-LN1 lock nut on a POLARIS-K1F1 low distortion mount.
These lock nuts are designed for use with our Polaris mounts with 1/4"-100 adjusters. Designed for long-term adjuster stability or applications that are exposed to shock and vibration, these lock nuts are pre-greased with the same ultra-high-vacuum-compatible, low-outgassing PTFE grease as the Polaris mounts and have been tested for adjuster fit.
To secure the lock nut on an adjuster, lightly tighten to a torque of approximately 4 to 8 oz-in (0.03 to 0.06 N·m). The beam can be held on target with the adjuster thumbscrew or hex key while lightly tightening the lock nut by hand or with a thin-head wrench or cone wrench; POLARIS-LN1 lock nuts have a 13 mm hex. To avoid cross threading the lock nut, place it against the adjuster and "unscrew" the lock nut until you feel a slight drop; then thread the lock nut onto the adjuster.
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The F25USK2 Knob is Compatible with our Polaris Mounts
This removable adjustment knob is compatible with many of our 1/4"-100 adjusters, including those used in the Ø1" and Ø2" Polaris Kinematic Mounts and our Polaris Kinematic Platform Mount. The larger Ø0.925" size provides additional angular resolution over the standard Polaris knobs.
Please note that this knob is not compatible with the POLARIS-K1C4, POLARIS-K1G4, POLARIS-K1S5, and POLARIS-K1S4 mounts with side hole adjusters.