Polaris® 5-Axis Kinematic Mount for Ø1.5" Optics


  • 3 Kinematic Adjusters for ±3.4° Tip/Tilt and 6 mm Z Travel
  • SM1.5-Threaded Bore with ±2.0 mm of X/Y Travel
  • Integrated Locking Mechanisms on X & Y Axes
  • Heat Treated to Minimize Temperature-Dependent Hysteresis

POLARIS-K15XY

SM1.5-Threaded
5-Axis Kinematic Mount

Front

Back

The front face
features an
SM1.5-threaded bore.

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Features

  • Five Axes of Adjustment
    • Pitch/Yaw: ±3.4° at ~5 mrad/rev
    • X/Y Translation with Integrated Locking Mechanism: ±2.0 mm at 195 µm/rev
    • Z Translationa: 6 mm at 254 µm/rev
  • SM1.5-Threaded (1.535"-40) Bore for Ø1.5" (38.1 mm) Optics up to 0.20" (5.0 mm) Thick
  • Matched Actuators and Body Provide Stability and Smooth Kinematic Adjustment
  • Extensive Testing Guarantees Less than 5 μrad Reflected Beam Shift after 15 °C Temperature Cycling (See Test Data Tab for Details)
  • Machined from Heat-Treated Stainless Steel with Low Coefficient of Thermal Expansion (CTE)
  • Passivated Stainless Steel Surface Ideal for Vacuum and High-Power Laser Cavity Applications

The Polaris® 5-Axis Kinematic Mount for Ø1.5" Optics is the ultimate solution for applications requiring stringent long-term alignment stability. The front plate features an SM1.5-threaded (1.535"-40) bore for mounting Ø1.5" optics or SM1.5-threaded components. The tip/tilt/Z adjusters may be locked using POLARIS-LN1 lock nuts (sold separately below) and Z-axis translation is achieved using all three of the adjusters on the back plate. The X- and Y-axis translation plates are secured using a patent-pending flexure preloading mechanism that is lockable using a setscrew with a ball tip that introduces minimal angular shifts during locking and unlocking. This design provides high holding force and pointing stability while allowing quick and easy installation of the optic. The X and Y adjusters can additionally be locked using POLARIS-LN05 lock nuts. Two mounting positions are possible for right- or left-handed orientations.

Optic Retention
This mount features an SM1.5-threaded bore that allows a variety of optical components to be secured. A stainless steel retaining ring is included with each mount; additional retaining rings can also be purchased separately by contacting Tech Support. Polaris optic bores are precision machined to achieve a fit that will provide optimum positional stability over changing environmental conditions such as temperature changes, transportation shock, and vibration. The performance will be diminished if this mount is used with optics that have an outer diameter tolerance greater than zero or smaller metric optic sizes (Ø37.5 mm). To order a mount designed for metric optics, please contact Tech Support.

Design
Machined from heat-treated stainless steel, Polaris mounts utilize precision-matched adjusters with ball contacts and sapphire seats to provide smooth kinematic adjustment. As shown on the Test Data tab, these mounts have undergone extensive testing to ensure high-quality performance. The Polaris design addresses all of the common causes of beam misalignment; please refer to the Design Features tab for detailed information.

Post Mounting
The POLARIS-K15XY mount is equipped with two sets of #8 (M4) counterbores for post mounting, as well as Ø2 mm alignment pin holes around the central mounting holes, allowing for precision alignments when paired with our posts for Polaris mirror mounts. See the Usage Tips tab for more recommendations about mounting configurations.

Cleanroom and Vacuum Compatibility
The POLARIS-K15XY mount is designed to be compatible with cleanroom and vacuum applications. See the Specs tab and the Design Features tab for details.

  • Z-axis translation is accomplished by turning all three tip/tilt adjusters equally in the same direction.
Item # POLARIS-K15XY
Optic Sizea Ø1.5"
Optic Thickness (Max) 0.20" (5.0 mm)
Tip/Tilt/Z Adjusters 1/4"-100 Matched Actuator/Body Pairs, 5/64" (2.0 mm) Hex Drive with Removable Knobs
X/Y Adjusters 3/16"-130 Matched Actuator/Body Pairs, 5/64" (2.0 mm) Hex Drive
Tip/Tilt Angular Range ±3.4°, ~5 mrad/revb
X/Y Travel Range ±2 mm / ±2 mm, 195 µm/rev
Max Front Plate Travel
(Z Axis, 3 Adjuster Pitch)
6 mm, 254 µm/rev
Measured Point-to-Point Mechanical
Resolution per Adjuster (Tip/Tilt)
5 µrad (Typical)
2 µrad (Achievable)
Measured Point-to-Point Mechanical
Resolution per Adjuster (X/Y)
5 µm (Typical)
Measured Adjuster Lock (Tip/Tilt)c 10 µrad (Typical)
Measured Beam Shift from
Locking Screw (per Axis)d
15 µrad (Typical)
5 µrad (Achievable)
Crosstalk (X/Y) <3.4 µm/rev
Orthogonality (X/Y) 90.0° ± 0.5°
Beam Deviatione <5 μrad
Recommended Optic Mounting Torque 5 - 18 oz-in for 5 mm Thick Optics
Maximum SM-Threaded Component
Mounting Torque
40 lb-in for SM1.5-Threaded Parts
Maximum Front Plate Payload 0.5 lb-in (0.05 N·m) / 0.5 lb (2.3 N)
Mountingf Two Sets of #8 (M4) Counterbores at 90°
Alignment Pin Holesg Two at Each Central Counterbore
Vacuum Compatibilityh 10-9 Torr at 25 °C with Proper Bake Out;
10-5 Torr at 25 °C without Bake Out;
DuPont Krytox® LVP High-Vacuum Grease Vapor Pressure:
10-13 Torr at 20 °C; 10-5 Torr at 200 °C;
DuPont Krytox® XHT-BDX High-Vacuum Grease Vapor Pressure:
10-14 Torr at 20 °C; 10-6 Torr at 200 °C;
EPO-TEK® 353ND (353NDPK) Epoxy Meets
Low Outgassing Standards NASA ASTM E595, Telcordia GR-1221
Cleaningh Passivated per ASTM-967 using Carpenter AAA Method
Operating Temperature Range -30 to 200 °C
  • For best performance, use optics with a diameter tolerance of up to +0/-0.004" (+0/-0.1 mm).
  • When the front plate is parallel to the back plate.
  • When locked using POLARIS-LN1 lock nuts.
  • Measured change in the alignment of a reflected beam from tightening the integrated locking screw.
  • After a 15 °C temperature cycle, a reflected beam returns to within 5 μrad of its original position for a Polaris mounted on a Ø1" post with a 3" beam height. Please see the Test Data tab for more details.
  • This mount can be used with standard 8-32 and M4 socket head cap screws for mounting without obstructing the transmissive beam path.
  • Standard DIN 7-m6 ground dowel pins are recommended. The recommended tolerance for the location of the mating dowel pin holes and threaded mounting hole is ±0.003".
  • This mount is assembled in a clean environment, chemically cleaned using the Carpenter AAA passivation method to remove sulfur, iron, and contaminants from the surface, and double vacuum bagged. Standard 8-32 and M4 cap screws are not rated for pressures below 10-5 Torr. Prior to placing any components in a sensitive vacuum system, a thorough pre-baking in a bake-out oven should be performed to remove all moisture and surface volatiles. Contact Tech Support for details.

Polaris® 5-Axis Kinematic Mount Test Data

The POLARIS-K15XY Translation Mount has undergone extensive testing to ensure high-quality performance. The POLARIS-K15XY mount had a Ø1.5" mirror installed and torqued down to 5 oz-in with the included SM1.5-threaded retaining ring. The mount was then installed side-by-side in a temperature-controlled environment on a Ø1" stainless steel post that was secured to a stainless steel optical table. The mount had its translation axes unlocked and 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 the tested mount was raised to above 40 °C, then the temperature of the mount was returned to the starting temperature. The results of this test are shown to the right.

Results: As can be seen in the plot to the right, when the Polaris mount was returned to its initial temperature, the angular position (both pitch and yaw) of the optic returned to within 5 µrad of its initial position. The performance of the mounts was tested further by subjecting them to repeated temperature change cycles. After each cycle, the mirror position reliably returned to within 5 µrad of its initial position.

Conclusions: The POLARIS-K15XY Mount is a high-quality, ultra-stable mount that will reliably return an optic to its original position after cycling through a temperature change. As a result, this mount is ideal for use in applications that require long-term alignment stability.


Click to Enlarge

Design Features of the POLARIS-K15XY Mount

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 optic 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 lens mount.

Thermal Hysteresis
The temperature in most labs is not constant due to factors such as air conditioning, the number of people in the room, and the operating states of equipment. Thus, it is necessary that all mounts used in an alignment-sensitive optical setup be designed to minimize any thermally induced alignment effects. Thermal effects can be minimized by choosing materials with a low coefficient of thermal expansion (CTE), like stainless steel. However, even mounts made from a material with a low CTE do not typically return the optic to its initial position when the initial temperature is restored. All the critical components of the POLARIS-K15XY mount are heat treated prior to assembly since this process removes internal stresses that can cause a temperature-dependent hysteresis. As a result, the alignment of the optical system will be restored when the temperature of the mount is returned to the initial temperature.

The method by which the lens is secured in the mount is another important design factor; this Polaris mount offers excellent performance without the use of adhesives. Instead, it has an SM1.5-threaded bore and a stainless steel retaining ring that holds the optic in place. The holding force provided by the stainless steel retaining ring is sufficient to keep the lens locked into place regardless of the ambient temperature. This bore also allows other SM1.5-threaded components to be secured in the mount.

Crosstalk
Crosstalk is minimized by carefully controlling the dimensional tolerances of the plates of the mount so that the X and Y actuators are orthogonal. In addition, sapphire seats are used at both contact points. Standard metal-to-metal actuator contact points will wear down over time. The polished sapphire seats of this Polaris mount, in conjunction with the hardened stainless steel actuator tips, maintain the integrity of the contact surfaces over time.

Drift and Backlash
In order to minimize the positional drift of the lens mount and backlash, it is necessary to limit the amount of play in the adjuster as well as the amount of lubricant used. When an adjustment is made to the actuator, the lubricant will be squeezed out of some spaces and built up in others. This non-equilibrium distribution of lubricant will slowly relax back into an equilibrium state. However, in doing so, this may cause the position of one of the mount's plates to move. The Polaris mounts use adjusters matched to the body that exceed all industry standards so very little adjuster lubricant is needed. These adjusters have a smooth feel that allows the user to make small, repeatable adjustments.

Cleanroom and Vacuum Compatibility
The POLARIS-K15XY is designed to be compatible with cleanroom and vacuum applications. It is chemically cleaned using the Carpenter AAA passivation method to remove sulfur, iron, and contaminants from the surface. After passivation, it is assembled in a clean environment and then double vacuum bagged to eliminate contamination when transported into a cleanroom.

Double Vacuum Bagging for Polaris Mounts
Click to Enlarge

Polaris mounts are shipped inside two vacuum bag layers.

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 grease applied to the dovetail mechanism is DuPont Krytox® XHT-BDX High-Vacuum Grease, which is also an ultra-high-vacuum-compatible, low-outgassing PTFE grease. When operating at pressures below 10-5 Torr, we highly recommend using an appropriate bake out procedure prior to installing the mount in order to minimize contamination caused by outgassing.

Cleanroom-Compatible Packaging
Each vacuum-compatible Polaris mount is packaged within two vacuum bag layers after assembly in a clean environment, as seen in the image to the right. The vacuum-tight fit of the bags stabilizes the mount, limiting translation of the front plate due to shocks during transportation. The tight fit also minimizes rubbing against the bag, preventing the introduction of bag material shavings that would contaminate the clean mount.

In the vacuum-sealing process, moisture-containing air is drawn out of the packaging. This eliminates unwanted reactions on the surface of the mount without the need for desiccant materials. The vacuum bags protect the mount from contamination by air or dust during transport and storage, and the double-vacuum bag configuration allows for a straightforward and effective cleanroom entry procedure. The outer bag can be removed outside of the cleanroom, allowing the contaminant-free inner bag to be placed into a clean container and transferred into the cleanroom while retaining the benefits of vacuum-bag packaging. Inside the cleanroom, the mount can be removed from the inner bag when ready for use.

Spanner Bit and Torque Driver Application
Click to Enlarge

Spanner bits and the TD24 torque driver can be used to mount optics in the POLARIS-K15XY mount.

Through thermal changes and vibrations, the POLARIS-K15XY 5-axis kinematic mount is designed to provide years of use. Below are some usage tips to ensure that the mount provides optimal performance.

Mounting Considerations
Due to its relatively low coefficient of thermal expansion, stainless steel was chosen as the material from which to fabricate the front and back plates of Polaris mounts. When mounting, we recommend using components fabricated from the same material, such as our Ø1" Posts for Polaris Mirror Mounts and Polaris Clamping Arm. These posts are made of stainless steel and provide two lines of contact with the mount, which help confine the bottom of the mount during variations in the surrounding temperature, thereby minimizing potential alignment issues.

To minimize the impact of vibrations and temperature changes, it is recommended that your setup has as low of a profile as possible. Using short posts will reduce the Y-axis translation caused by temperature variations and will minimize any movements caused by vibrations. Mount the Polaris directly onto a flat surface such as a breadboard using a 8-32 to 1/4"-20 thread adapter (Item # AE8E25E) or M4 x 0.7 to M6 x 1.0 adapter (Item # AE4M6M) with a beam height of 1.40" (35.6 mm). Using this mounting method, the instability introduced by a post will be eliminated.

Optic Mounting
Since an optic is prone to movement within its mounting bore, all optics should be mounted with the Polaris out of the setup to ensure accurate mounting that will minimize misalignment effects. As shown to the right, we recommend using a TD24 torque wrench with an SPB1.5 Spanner Bit for SM1.5-threaded Polaris mounts. See the Specs tab for recommended torques. Over torquing the optic retaining rings can result in dramatic surface distortions.

Mounting SM1.5-Threaded Components
Since the front optic plate of the Polaris mount can move independently from the other plates, it is important to hold all the plates together while mounting SM-threaded components. This ensures that the front plate will not rotate with respect to the other plates and damage the flexure between them.

Mount Alignment
During alignment, minimized deflection will be achieved if the mount's front plate is kept parallel to the base plate. This ensures even thermal expansion of all the adjustment screws, causing the mounted optic to translate in the Z direction as opposed to rotating during temperature changes.

Front Plate Position
Although the mount is designed to allow tip/tilt adjustments of up to 6.8°, to achieve the best performance, it is recommended that the front plate be kept as parallel as possible to the back plate. This ensures the highest stability of the adjustments.

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.

Translation Limits
The X and Y axes of the POLARIS-K15XY mount translate ±2.0 mm from the optic's nominal center. To prevent accidental damage to the mount, translation limit stops are placed at the ends these translation ranges. Care should be taken when actuating the adjuster screws near the limits to prevent overdriving the mount and causing damage.

The Z-axis translation of the front plate is 6 mm maximum, measured from the shipped position (approximately 3 mm and parallel to the back plate). The installed knobs will prevent overdriving this limit, so care should be taken if the knobs are removed. There will be no limit stops to prevent damage if knobs are removed and Z translation is adjusted beyond the 6 mm limit.

Polish and Clean the Points of Contact
We highly recommend that the points of contact between the mount and the post, as well as the post and the table, are clean and free of scratches or defects. For best results, we recommend using a polishing stone to clean the table’s surface and a polishing pad (Item # LFG1P) for the top and bottom of the post as well as the bottom of the mount.

Not Recommended
We do not recommend taking the adjusters out of the body, as this can contaminate the threading and reduce the fine adjustment performance significantly. Also, do not pull the front plate away as it might stretch the springs beyond their operating range or crack the sapphire seats.

Adjuster Lock Nuts
The POLARIS-K15XY mount features integrated locking for X and Y axis travel. It is also compatible with the POLARIS-LN05 and POLARIS-LN1 adjuster lock nuts on the X/Y and tip/tilt/Z adjusters, respectively. For long term X/Y travel stability, we recommend using both the adjuster lock nuts and the translation locks.

To avoid cross threading a lock nut 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 left). 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.

Threading Specifications

The following is a general overview of screw threading. For more details regarding specifications and dimensions, please consult the Machinery's Handbook, available for purchase at many bookstores.

Features of a Thread
A thread consists of three repeating features: a crest, flank, and root (see drawing to the right). Except in special cases, threads have symmetrical sides inclined at equal angles when a vertical line is drawn through the center of a crest or root. The distance between corresponding points on adjacent threads is known as the pitch of the thread. The flank angle is defined as the angle the flank makes with a perpendicular ray drawn from the screw axis. Unless otherwise stated, threads have a flank angle of 30°, resulting in a total angle between flanks of 60°. Each feature is shown in the diagram to the right.

The major diameter is taken from the crests of a thread while the minor diameter is taken from the roots. For most screws, crests and roots do not terminate at a sharp point, so crest and root truncation values are included in the definitions of major and minor diameter. The pitch diameter is approximately halfway between the major and minor diameters.

Thread Form
A thread form is a set of rules that define the features' scale relative to one another. Common thread forms include the Unified Screw Thread Form, used in the United States of America and measured in imperial units, and the ISO Metric Screw Thread Form, used in many parts of the world and measured with the International System of Units. There are many thread forms in the Unified screw thread standard designated by either UN, which defines a flat root contour, or UNR, which defines a round root contour. These can be further described by appending more letters. For example, an extremely fine thread with a flat root contour is designated UNEF. Those forms which are not standardized by the Unified screw thread system are designated UNS.

Thread Series
Most screws are identified by their thread series. Thread series are denoted by the major diameter and density of threads. Unified threads specify density in threads per inch, while Metric threads specify the thread pitch. For example, in the Unified nomenclature, a 1/4"-20 cap screw has a 1/4" diameter barrel and the pitch is 20 threads per inch (TPI). In metric nomenclature, an M4 x 0.7 cap screw has a 4 mm barrel and the pitch is 1 thread per 0.7 mm. The term M4 x 0.7 is often shortened to just M4.

Unified Thread Class Tolerancing
Location Loose Optimal Strict
Internal 1B 2B 3B
External 1A 2A 3A
Metric Thread Tolerance Positions
Location Loose Optimal Strict
Internal - G H
External e or f g h
Metric Thread Tolerance Grades
Dimension Location Tolerance Gradesa
Minor Diameter Internal 4, 5, 6, 7, 8
Major Diameter External 4, 6, 8
Pitch Diameter Internal 4, 5, 6, 7, 8
External 3, 4, 5, 6, 7, 8, 9
  • The tolerance becomes looser as the grade increases. The underlined grades are used with normal lengths of thread engagement.

Thread Class
The tolerances and allowances on a thread series are given by a thread class. Unified thread classes are alphanumeric identifiers starting with a number from 1 through 3, where 1 is the loosest tolerance and 3 is the tightest, and either A for external threading or B for internal threading.

Metric threads have a slightly more complex tolerancing method that uses tolerancing grades, designated by a number 3 through 9; and tolerancing positions, which use letters e through h. Grades provide a measure of the tolerance itself: the smaller the number, the tighter the tolerance. Positions denote the distance of the tolerance from the pitch diameter. Uppercase positioning letters indicate internal threads while lowercase positioning letters indicate external threads.

Quoting from the Machinery's Handbook, 29th Edition, p. 1885: "To designate the tolerance class, the grade and position of the pitch diameter is shown first followed by that for the major diameter in the case of the external thread or that for the minor diameter in the case of the internal thread, thus 4g6g for an external thread and 5H6H for an internal thread. If the two grades and positions are identical, it is not necessary to repeat the symbols, thus 4g, alone, stands for 4g4g and 5H, alone, stands for 5H5H."

Thorlabs' SM Series Threads
Threading specifications for our SM threads, utilized in our lens tube and cage system components, are given below so that you can machine mating components to suit your application. Most SM series threads utilize a non-standard Unified thread form, indicated by the letters UNS, with a 30° flank angle and a thread class of 2A and 2B. The exception is our SM30 series thread, which is a Metric thread form with a 30° flank angle and a tolerance of 6H/6g. We also offer products with C-Mount and RMS threads, and the specifications for these threads are given below for reference. Please note that other manufacturers may have different tolerances for C-Mount and RMS threads. For other thread specifications that are not listed here, please contact Tech Support.

SM05 Threading: Ø1/2" Lens Tubes, 16 mm Cage Systems
External Thread, 0.535"-40.0 UNS-2A Internal Thread, 0.535"-40.0 UNS-2B
Max Major Diameter 0.5340" Min Major Diameter 0.5350"
Min Major Diameter 0.5289" Min Pitch Diameter 0.5188"
Max Pitch Diameter 0.5178" Max Pitch Diameter 0.5230"
Min Pitch Diameter 0.5146" Min Minor Diameter (and 83.3% of Thread) 0.508"
Max Minor Diameter 0.5069" Max Minor Diameter (and 64.9% of Thread) 0.514"
RMS Threading: Objective, Scan, and Tube Lenses
External Thread, 0.800"-36.0 UNS-2A Internal Thread, 0.800"-36.0 UNS-2B
Max Major Diameter 0.7989" Min Major Diameter 0.8000"
Min Major Diameter 0.7934" Min Pitch Diameter 0.7820"
Max Pitch Diameter 0.7809" Max Pitch Diameter 0.7866"
Min Pitch Diameter 0.7774" Min Minor Diameter (and 83.3% of Thread) 0.770"
Max Minor Diameter 0.7688" Max Minor Diameter (and 64.9% of Thread) 0.777"
C-Mount Threading: Machine Vision Lenses, CCD/CMOS Cameras
External Thread, 1.000"-32.0 UN-2A Internal Thread, 1.000"-32.0 UN-2B
Max Major Diameter 0.9989" Min Major Diameter 1.0000"
Min Major Diameter 0.9929" Min Pitch Diameter 0.9797"
Max Pitch Diameter 0.9786" Max Pitch Diameter 0.9846"
Min Pitch Diameter 0.9748" Min Minor Diameter (and 83.3% of Thread) 0.966"
Max Minor Diameter 0.9651" Max Minor Diameter (and 64.9% of Thread) 0.974"
SM1 Threading: Ø1" Lens Tubes, 30 mm Cage Systems
External Thread, 1.035"-40.0 UNS-2A Internal Thread, 1.035"-40.0 UNS-2B
Max Major Diameter 1.0339" Min Major Diameter 1.0350"
Min Major Diameter 1.0288" Min Pitch Diameter 1.0188"
Max Pitch Diameter 1.0177" Max Pitch Diameter 1.0234"
Min Pitch Diameter 1.0142" Min Minor Diameter (and 83.3% of Thread) 1.008"
Max Minor Diameter 1.0068" Max Minor Diameter (and 64.9% of Thread) 1.014"
SM30 Threading: Ø30 mm Lens Tubes
External Thread, M30.5 x 0.5 – 6H/6g Internal Thread, M30.5 x 0.5 – 6H/6g
Max Major Diameter 30.480 mm Min Major Diameter 30.500 mm
Min Major Diameter 30.371 mm Min Pitch Diameter 30.175 mm
Max Pitch Diameter 30.155 mm Max Pitch Diameter 30.302 mm
Min Pitch Diameter 30.059 mm Min Minor Diameter (and 83.3% of Thread) 29.959 mm
Max Minor Diameter 29.938 mm Max Minor Diameter (and 64.9% of Thread) 30.094 mm
SM1.5 Threading: Ø1.5" Lens Tubes
External Thread, 1.535"-40 UNS-2A Internal Thread, 1.535"-40 UNS-2B
Max Major Diameter 1.5339" Min Major Diameter 1.535"
Min Major Diameter 1.5288" Min Pitch Diameter 1.5188"
Max Pitch Diameter 1.5177" Max Pitch Diameter 1.5236"
Min Pitch Diameter 1.5140" Min Minor Diameter (and 83.3% of Thread) 1.508"
Max Minor Diameter 1.5068" Max Minor Diameter (and 64.9% of Thread) 1.514"
SM2 Threading: Ø2" Lens Tubes, 60 mm Cage Systems
External Thread, 2.035"-40.0 UNS-2A Internal Thread, 2.035"-40.0 UNS-2B
Max Major Diameter 2.0338" Min Major Diameter 2.0350"
Min Major Diameter 2.0287" Min Pitch Diameter 2.0188"
Max Pitch Diameter 2.0176" Max Pitch Diameter 2.0239"
Min Pitch Diameter 2.0137" Min Minor Diameter (and 83.3% of Thread) 2.008"
Max Minor Diameter 2.0067" Max Minor Diameter (and 64.9% of Thread) 2.014"
SM3 Threading: Ø3" Lens Tubes
External Thread, 3.035"-40.0 UNS-2A Internal Thread, 3.035"-40.0 UNS-2B
Max Major Diameter 3.0337" Min Major Diameter 3.0350"
Min Major Diameter 3.0286" Min Pitch Diameter 3.0188"
Max Pitch Diameter 3.0175" Max Pitch Diameter 3.0242"
Min Pitch Diameter 3.0133" Min Minor Diameter (and 83.3% of Thread) 3.008"
Max Minor Diameter 3.0066" Max Minor Diameter (and 64.9% of Thread) 3.014"
SM4 Threading: Ø4" Lens Tubes
External Thread, 4.035"-40 UNS-2A Internal Thread, 4.035"-40.0 UNS-2B
Max Major Diameter 4.0337" Min Major Diameter 4.0350"
Min Major Diameter 4.0286" Min Pitch Diameter 4.0188"
Max Pitch Diameter 4.0175" Max Pitch Diameter 4.0245"
Min Pitch Diameter 4.0131" Min Minor Diameter (and 83.3% of Thread) 4.008"
Max Minor Diameter 4.0066" Max Minor Diameter (and 64.9% of Thread) 4.014"

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If your application requires an optic mount design that is not available below, please contact Tech Support.

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, a fixed monolithic mirror mount and fixed optic mounts, an XY translation mount, 5-axis kinematic mount, and a kinematic platform mount. Refer to the tables below for our complete line of Polaris mounts, grouped by mount type, optic bore size, and then arranged by optic retention method and adjuster type (or intended application in the case of fixed mounts). We also offer a line of accessories that have been specifically designed for use with our Polaris mounts; these are listed in the table to the lower right. Note that the tables below list Item # suffixes that omit the "POLARIS" prefix for brevity. Click the photos below for details.

Polaris Mount Optic Retention Methods
Side Lock SM Threaded Low Distortion Glue-In
Polaris Mount Adjuster Types
Side Hole Hex Adjuster Knobs Adjuster
Lock Nuts
Piezo Adjusters Vertical-Drive Adjusters
Polaris Kinematic Mounts for Round Optics
Optic Retention Method Side Lock SM Threaded Low Distortion Glue-In
Ø1/2" Optics
2 Side Hole Adjusters - - - -K05C4
-K05G4
2 Hex Adjusters -K05S1 -K05T1 -K05F1 -
2 Adjusters with Lock Nuts -K05S2 -K05T2 -K05F2 -
2 Piezoelectric Adjusters -K05P2 - - -
3 Hex Adjusters -K05 - - -
3 Adjusters with Lock Nuts - -K05T6 -K05F6 -
Ø19 mm (3/4") Optics
2 Side Hole Adjusters -K19S4 - -K19F4/M -K19G4
Ø25 mm Optics
2 Side Hole Adjusters -K25S4/M - -K25F4/M -
Ø1" Optics
2 Side Hole Adjusters -K1S4 - - -K1C4
-K1G4
2 Hex Adjusters -K1E2
-K1-2AH
-K1T2 -K1F2 -
2 Adjuster Knobs - -K1T1 -K1F1 -
2 Piezoelectric Adjusters -K1S2P - - -
2 Vertical Adjusters -K1VS2
-K1VS2L
- - -
3 Side Hole Adjuster -K1S5 - - -
3 Hex Adjusters -K1E3
-K1-H
-K1T3 - -
3 Adjuster Knobs -K1E
-K1
-K1T -K1F -
3 Piezoelectric Adjusters -K1S3P - - -
Optic Retention Method Side Lock SM Threaded Low Distortion Glue-In
Ø1.5" Optics
2 Side Hole Adjusters -K15S4 - -K15F4 -
2 Vertical Adjusters -K15VS2
-K15VS2L
- - -
3 Adjuster Knobs (Tip/Tilt/Z) &
2 Hex Adjusters (X/Y)
- -K15XY - -
Ø50 mm Optics
2 Side Hole Adjusters -K50S4/M - -K50F4/M -
Ø2" Optics
2 Hex Adjusters -K2S2 -K2T2 -K2F2 -
2 Adjuster Knobs -K2S1 -K2T1 -K2F1 -
2 Piezoelectric Adjusters -K2S2P - - -
2 Vertical Adjusters -K2VS2
-K2VS2L
- - -
3 Hex Adjusters -K2S3 -K2T3 -K2F3 -
3 Adjuster Knobs -K2 -K2T -K2F -
Ø3" Optics
2 Side Hole Adjusters -K3S4 - - -
3 Side Hole Adjusters -K3S5 - - -
Ø4" Optics
2 Side Hole Adjusters - - -K4F4 -
Ø6" Optics
2 Side Hole Adjusters - - -K6F4 -
Polaris XY Translation Mounts for Round Optics
Optic Retention Method SM Threaded Representative Photos
Ø1" Optics
2 Hex Adjusters (X/Y) -1XY
Ø1.5" Optics
2 Hex Adjusters (X/Y) &
3 Adjuster Knobs (Tip/Tilt/Z)
-K15XY
Polaris Fixed Mounts for Round Optics
Optic Retention Method Side Lock Glue-In Representative Photos
Ø1/2" Optics



Optimized for Mirrors - -C05G
Optimized for Beamsplitters -B05S -B05G
Optimized for Lenses - -L05G
Ø19 mm (3/4") Optics
Optimized for Mirrors -19S50/M -
Ø1" Optics
Optimized for Mirrors - -C1G
Optimized for Beamsplitters -B1S -B1G
Optimized for Lenses - -L1G
Ø2" Optics
Optimized for Mirrors - -C2G
Optimized for Beamsplitters -B2S -
Polaris Kinematic 1.8" x 1.8" Platform Mount
Optomech Retention Method Tapped Holes &
Counterbores
2 Adjuster Knobs -K1M4(/M)
Accessories for Polaris Mounts
Description Representative Photos
Ø1" Posts for Polaris Mounts
Polaris Non-Bridging Clamping Arms
Polaris 45° Mounting Adapter

Polaris® 5-Axis Kinematic Mount for Ø1.5" Optics

Dowel Pin Holes
Click to Enlarge

Polaris mounts have two holes for Ø2 mm alignment pins by the central #8 (M4) mounting bore for alignment.
Translation Features
Click to Enlarge

Kinematic and Y-axis translation features are shown above. The X-axis adjuster and lock are also visible but not labelled.
  • ±3.4° Tip/Tilt Range
  • ±2.0 mm X/Y Translation Range and 6 mm Z Translation
  • SM1.5 (1.535"-40) Threading for Mounting Ø1.5" Optics up to 0.20" (5 mm) Thick
  • Matched Actuator/Body Pairs
  • <5 µrad Deviation after Temperature Cycling (See the Test Data Tab for Details)

The POLARIS-K15XY 5-Axis Kinematic Mount for Ø1.5" Optics offers ±3.4° of tip/tilt adjustment, ±2.0 mm of X/Y travel, and 6 mm of Z translation and is designed to provide easy high-resolution adjustment and long-term alignment stability. The mount features a patent pending flexure preloading mechanism that keeps the translation smooth and repeatable. It is also designed to be compatible with cleanroom and vacuum applications.

The POLARIS-K15XY mount features three 1/4"-100 adjusters for tip/tilt/Z translation and two 3/16"-130 adjusters for X/Y translation. The tip/tilt/Z actuators feature removable knobs with a 5/64" (2.0 mm) hex and the X/Y actuators have 5/64" (2.0 mm) hex drives. With the knobs removed, all actuators may be adjusted with our HKTS-5/64 Hex Key Thumbscrews (sold separately below), the hex on the end of the SA1 tool, or any other 5/64" (2.0 mm) hex wrench.

The tip/tilt/Z adjusters can be locked using POLARIS-LN1 lock nuts (sold separately below) and the X/Y travel adjusters on this mount can be locked using the integrated translation locks with a 5/64" (2.0 mm) hex or with POLARIS-LN05 lock nuts (also sold separately below). Note that the integrated locks for the X and Y axes are adjacent to the adjuster for the other axis, as illustrated for the Y-axis in the left photo above. For long term X/Y locking stability, we recommend using both the adjuster lock nuts and the translation locks.

A stainless-steel retaining ring (included) is used to hold optics up to 0.20" (5 mm) thick. Additional retaining rings can also be purchased separately by contacting Tech Support. This mount is also equipped with two engraved X- and Y-axis scales that provide a translation reference with 0.5 mm tick spacing.

Post mounting is provided by four #8 (M4) bores. For custom mounting configurations, two holes for Ø2 mm alignment pins are located on each mounting face (as shown in the photo above) for setting a precise location and mounting angle. Standard 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.

Please note that these mounts are designed for Ø1.5" optics and are not intended for use with Ø37.5 mm metric optics.

Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
POLARIS-K15XY Support Documentation
POLARIS-K15XYNEW!Customer Inspired! Polaris 5-Axis Kinematic Mount for Ø1.5" Optics, #8 (M4) Mounting Bores
$1,650.00
Lead Time

5/64" Hex Key Adjusters

POLARIS-K12AH with HKTS-5/64 Adjuster
Click for Details

POLARIS-K1-2AH with HKTS-5/64 Adjuster
  • For Convenient Adjustment of 5/64" and 2 mm Hex-Driven Actuators
  • Red Anodized Adjustment Knob with Engraved Hex Size
  • Replaceable Hex Tip
  • Sold in Packages of 4

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.

Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
HKTS-5/64 Support Documentation
HKTS-5/64Customer Inspired! 5/64" (2 mm) Hex Key Thumbscrew, 4 Pack
$27.86
Today

Adjuster Lock Nuts for 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 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.


Click for Details

POLARIS-LN05 Lock Nuts on a POLARIS-K19S4 Mount
  • Provide Long Term Adjuster Stability
  • Compatible with Select Polaris Mounts
  • POLARIS-LN05 Lock Nut has 3/16"-130 Internal Threading
  • POLARIS-LN1 Lock Nut has 1/4"-100 Internal Threading

These lock nuts are designed for use with Polaris kinematic mounts that do not use low-profile adjusters. The POLARIS-LN05 lock nut can be used with 3/16"-130 adjusters, while the POLARIS-LN1 lock nut is for 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.

For applications that require frequent tuning of the adjusters, the lock nuts only need to be lightly tightened by hand to a torque of approximately 4 to 8 oz-in (0.03 to 0.06 N·m). If long term stability is required, the torque wrenches below can be used to apply the appropriate amount of torque to each lock nut (see the table below for torque values). POLARIS-LN05 lock nuts require a 6 mm hex tool for tightening, while POLARIS-LN1 lock nuts require a 13 mm hex tool. 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.

Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Imperial Price Available
POLARIS-LN05 Support Documentation
POLARIS-LN053/16"-130 Lock Nut, 6 mm Hex, Stainless Steel
$14.05
Today
POLARIS-LN1 Support Documentation
POLARIS-LN11/4"-100 Lock Nut, 13 mm Hex, Stainless Steel
$9.14
Today

1/4"-100 Adjuster Locking Collar for Polaris® Mounts

  • Provides Long Term Adjuster Stability
  • Compatible with Select Polaris Mounts
  • Low Profile: Ø0.33" (Ø8.4 mm) x 0.08" (1.9 mm) Thick
  • Tighten Along Rotational Axis Using the POLARIS-T2 Spanner Wrench
  • TW13 Torque Wrench
    • Has a Preset Torque Value of 32 oz-in (0.23 N•m)
    • Break-Over Design Ensures Proper Torque is Applied

This locking collar is compatible with Polaris mounts that have 1/4"-100 adjusters, excluding the piezo-driven mounts and mounts with low-profile adjusters (Item #s POLARIS-K1-H and POLARIS-K1-2AH). Designed for long-term adjuster stability or applications that are exposed to shock and vibration, these locking collars 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.

The POLARIS-T2 spanner wrench has been specifically designed for use in securing the POLARIS-LNS1 locking collar. The double spanner head enables complete engagement while the design allows locking collar adjustments to be along the same line as the adjuster itself. A center through hole allows a 2 mm ball driver to pass through the spanner wrench, so that the adjuster can be held in position while the locking collar is engaged.

For applications that require frequent tuning of the adjusters, the locking collar only needs to be lightly tightened to a torque of approximately 4 to 8 oz-in (0.03 to 0.06 N·m). For long term stability, we recommend tightening to a torque of 32 oz-in, which can be achieved by using our TW13 preset torque wrench (sold below) in combination with the POLARIS-T2 spanner wrench. To avoid cross threading the locking collar, place it against the adjuster and "unscrew" the collar until you feel a slight drop; then thread the collar onto the adjuster.

The TW13 13 mm Hex Torque Wrench has a preset torque value of 32 oz-in and is compatible with the POLARIS-T2 spanner wrench, POLARIS-LN1 lock nut, and POLARIS-LN4 lock nut. When the preset torque value has been achieved, the break-over design will cause the pivoting joint to "break." The wrench's hex head will move back into place once the force is removed. This design prevents excess force from being applied to the lock nut.

Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Imperial Price Available
POLARIS-LNS1 Support Documentation
POLARIS-LNS11/4"-100 Locking Collar, Stainless Steel
$10.76
Today
+1 Qty Docs Part Number - Universal Price Available
POLARIS-T2 Support Documentation
POLARIS-T2Spanner Wrench for POLARIS-LNS1 Locking Collar
$53.81
Today
TW13 Support Documentation
TW13Customer Inspired! 13 mm Preset Torque Wrench for Polaris Lock Nuts, 32 oz-in
$126.69
Lead Time

1/4"-100 Large Adjustment Knob

Large Polaris Knob
Click to Enlarge

F25USK2 Knob Shown Attached to a POLARIS-K1 Mirror Mount
  • Ø0.925" Knob for Additional Angular Resolution
  • Clearance Hole Allows Access to Hex Socket of the Adjuster

This removable adjustment knob is compatible with many of our 1/4"-100 adjusters, including those used in the Ø1", Ø1.5", 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 the F25USK2 knob is not compatible with Polaris mounts that use side-hole adjusters. The recessed bore of knob is not deep enough to allow the knob to engage the threads on the side-hole adjuster.

Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Imperial Price Available
F25USK2 Support Documentation
F25USK2Ø0.925" 1/4"-100 Removable Adjuster Knob
$9.79
Today