120° Clear-Edge, Pitch-Adjustable Flexure Mount

  • Thin-Profile Flexure Mount for Ø1" (Ø25.4 mm) Optics
  • ±4° Pitch Adjustment for Beam Leveling
  • 120° Clear Edge


Application Idea

PFM1 Mount on Ø1/2" Post (Mirror Not Included)
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Schematic of the PFM1


  • 120° Clear-Edge Flexure Mount for Ø1" (Ø25.4 mm) Optics
  • Compact, 0.36" (9.1 mm) Thick Design 
  • 6-80 Adjuster Provides ±4° Pitch Adjustment
  • Holds Ø1" (Ø25.4 mm) Optics 0.15" to 0.28" (3.8 mm to 7.1 mm) Thick
  • Ø0.93" (Ø23.5 mm) Transmissive Clear Aperture
  • Mount to Ø1/2" Posts using Bottom-Located 8-32 (M4) Tapped Hole

The PFM1(/M) Clear-Edge Flexure Mount holds Ø1" (Ø25.4 mm) mirrors and beamsplitters and provides ±4° of pitch adjustment. A thin, 0.36" (9.1 mm) profile allows this mount to fit into tight spaces where space constraints are a concern. The one-piece flexure design minimizes drift during use, making this mount ideal for beam-leveling applications. The mount features a 120° exposed optic edge, which, like our clear-edge kinematic mirror mounts, allows a beam to pass near the exposed outer radius of the optic without clipping on the mount's front housing. This is useful for combining two beams at near-normal incidence or picking off a beam that is propagating closely to a second beam.

A top-located, nylon-tipped setscrew with a 5/64" (2 mm) hex is used to secure optics 0.15" to 0.28" (3.8 mm to 7.1 mm) thick. Light is typically incident on an optic from the engraved side of the mount. However, when used with transmissive optics or from the opposite side, the back lip used to hold the optic introduces a Ø0.93" (Ø23.5 mm) clear aperture. The PFM1(/M) can be mounted to Ø1/2" optical posts via the bottom-located 8-32 (M4) tapped hole. 

As seen in the drawing to the right, the 6-80 fine pitch adjuster with a 5/64" (2 mm) hex provides ±4° of pitch adjustment. The mount is equipped with a limit stop that prevents overextension of the flexure mount; forcing the adjuster beyond this point can damage the mount. Also, please note that the flexure-based design of this mount introduces a small amount of natural hysteresis when adjusting the pitch of the mount. 

Thorlabs also offers the TPA01, which offers pitch-adjustment for fixed optic mounts. For adjustment of pitch, tip, and tilt, Thorlabs has a full line of kinematic mounts for mirrors and optics of varying sizes. Additionally, we also offer translation and rotation mounts to control the position and orientation, respectively, of an optic within a setup.

Posted Comments:
klaus.ertel  (posted 2018-11-16 12:42:48.173)
A 2-inch version of the PFM1 would be great.
YLohia  (posted 2018-11-16 08:43:18.0)
Hello, thank you for contacting Thorlabs. Custom items can be ordered by contacting your local Tech Support (techsupport.uk@thorlabs.com). We will reach out to you directly to discuss the possibility of offering this.
Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Imperial Price Available
PFM1 Support Documentation
PFM1120° Clear-Edge Flexure Mount for Ø1" (Ø25.4 mm) Optics, 8-32 Tapped Hole
+1 Qty Docs Part Number - Metric Price Available
PFM1/M Support Documentation
PFM1/M120° Clear-Edge Flexure Mount for Ø1" (Ø25.4 mm) Optics, M4 Tapped Hole