Rear-Loaded, Clear-Quadrant Kinematic Mirror Mounts

  • Mounts Ø1/2" Optics
  • Design Allows Optic to be Reinserted with High Degree of Repeatability
  • Ideal for Application in Laser Cavity


Front View

Single Point/Stop for
Precise Mirror Positioning


Back View


Front View

Related Items

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  • Angular Adjustment Range: ±2°
  • Adjuster Provides 13 mrad/rev
  • Height of Center of Mirror: 0.58" (14.7 mm)
  • Back Surface Engraved for Realignment of Removed Optics
  • Fabricated from Black Anodized Aluminum
  • Post-Mountable via 8-32 (M4) Mounting Hole

These multi-functional clear-quadrant mirror mounts load Ø1/2" (12.7 mm) mirrors from the back side of the front plate to ensure that the optic can be reinserted with a high degree of repetition. The single point of contact at the front of the mount, which is shown in the detail image above, is a kinematic stop against which the front surface of the mirror rests while locked by a nylon-tipped setscrew. The witness line on the back side of the mount makes it possible to rotationally orient the optic with a user-inscribed mark on the back side of the mirror. These mounts feature 3/16"-100 TPI adjusters. The HKTS-5/64 hex adjuster can be used as a temporary adjuster knob, and the LN19100 bronze locking nut is available to lock the adjusters once the desired position is reached.

These mounts are also recommended for use in tight spaces; one side of the mount has been machined away to prevent potential obstruction to the beam path. The rear-loaded mounts are ideal for use in laser cavities, since the mirror can be removed without disturbing the alignment of the cavity.

For applications requiring low drift and low distortion, Thorlabs offers Polaris™ Low-Distortion Mirror Mounts. These mounts approximate a clear quadrant design due to the unobstructed mirror edge. Thorlabs also offers a variety of other two and three adjuster mirror mounts including our other high-stability Polaris™ Mirror Mounts.

Posted Comments:
sjackel  (posted 2017-11-26 03:40:47.343)
What is the minimum thickness optic that can be mounted in the KM05FL
nbayconich  (posted 2017-12-05 03:35:11.0)
Thank you for contacting Thorlabs. The minimum optic thickness for these optical mounts is 3.8mm.
gregor.kupka  (posted 2014-01-27 19:19:53.377)
Hello Madam, Hello Sir, I am looking for a Ø1/2" optic mount like the "KS05 Ø1/2" Precision Kinematic Mirror Mount" with thee adjusters, but with these notch like the KM05FL. --> so in principal a KM05FL with thee precise adjusters. Would it be possible to combine these parts? Best regards Gregor
jlow  (posted 2014-01-30 02:15:33.0)
Response from Jeremy at Thorlabs: I will contact you about quoting this. We also have the POLARIS-K05F6 which might be of interest to you as well.
kedves  (posted 2013-11-29 18:43:49.653)
Dear Thorlabs, Do you offer rear-loaded mirror mounts with high degree of repeatability for 1" optics too? As far as I remember, there used to be such a product in your selection. With Thanks, MK
cdaly  (posted 2013-12-04 03:54:17.0)
Response from Chris at Thorlabs: Thank you for your inquiry. We do have a few options for 1" mirrors which are rear loaded. The KM100CP from the rear in order to keep the front face of an optic centered over a post. The D-shaped mirror mount KM100D(L) could be used as well. Though it is not strictly read loaded, the optic is mounted via the front face as well and this would provide access to an unobstructed edge as with the KM05F(L/R). The last option would be the POLARIS-K1F6, which is rear loaded as well, and has higher precision actuator screws than the first two options, while providing a low distortion and thermal stability.
tcohen  (posted 2012-09-20 12:13:00.0)
Response from Tim at Thorlabs to Marcel: Thank you for your feedback! We can often make vacuum compatible versions of our products. It would be great to discuss your application with you in order to be able to offer these solutions and also get your feedback on whether there is anything missing in our catalog that would be useful for you working in vacuum. I will contact you directly to discuss this.
m.snels  (posted 2012-09-19 04:39:23.0)
I've always used your mirror mounts for laboratory use and I'm very satisfied with them. Now I need mirror mounts for use under vacuum. Do you sell mirror mounts and related items (xyz mounts) for use under vacuum, that is with low outgassing ? Best regards Marcel Snels
Adam  (posted 2010-04-23 15:34:20.0)
A response from Adam at Thorlabs to jmills: Thank you for the product suggestion. I will forward this information to our mechanical engineers as a customer inspired new product idea. If it gets adopted, we will let you know.
jmills  (posted 2010-04-22 15:22:51.0)
Would be nice to offer a kinematic mount where the mirror protrudes over the edge of the mount a little more. There is still a 0.160 space between two round mirros when the mounts are position in a 90 degree inclusive angle. Imagine using two mirror mounts on the leg of an inteferometer where a small beam splitter is used.
Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Imperial Price Available
KM05FL Support Documentation
KM05FLRear-Loaded Left-Handed Clear-Quadrant Mirror Mount
KM05FR Support Documentation
KM05FRRear-Loaded Right-Handed Clear-Quadrant Mirror Mount
+1 Qty Docs Part Number - Metric Price Available
KM05FL/M Support Documentation
KM05FL/MRear-Loaded Left-Handed Clear-Quadrant Mirror Mount, Metric
KM05FR/M Support Documentation
KM05FR/MRear-Loaded Right-Handed Clear-Quadrant Mirror Mount, Metric