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Ø2" Adapters for Unmounted Optics

  • Mounting Solutions for Ø1" to Ø48 mm Optics
  • Adapt Optics to Mounts with Either Ø2" Bore or Internal SM2 Threading
  • Setscrew or Retaining Ring for Optic Retention


Ø1" Smooth Central Bore
Ø2" Smooth Outer Surface


Internally M42.5 x 0.5 Threaded
Central Bore, Externally SM2 Threaded


Ø1.51" Smooth Central Bore,
Externally SM2 Threaded


Internally SM1-Threaded
Central Bore, Ø2" Smooth
Outer Surface

Related Items

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Selection Guide
Optic RetentionSmooth 2" Outer DiameterExternally SM2-Threaded Outer Surface
Smooth Bore
w/ Setscrew
Adapters for Ø1", Ø30 mm, or Ø1.5" OpticsAdapter for Ø1.5" Components
Close Approach Dual
Bore w/ Setscrew
Adapter for Ø1" Optics-
Internal Threads
w/ Retaining Rings
Adapter for Ø1" OpticsAdapters for Optics between
Ø30 mm and Ø48 mm
Smooth Bore
w/ Setscrew
Adapter for Ø1.2" Components

Thorlabs offers these Ø2" adapters for unmounted optics to easily integrate various optic diameter standards into Ø2" optomechanical systems, including optic mounts and lens tubes (see the Selection Guide to the right). The unthreaded adapters presented here are double-bored to provide 2 lines of mounting contact for Ø1", Ø30 mm, or Ø1.5" optics. Our externally SM2- (2.035"-40) threaded adapters with internally threaded central bores can house optics ranging from Ø30 mm to Ø48 mm. A Ø2" adapter with internal SM1 (1.053"-40) threading for Ø1" optics and and externally SM2-threaded adapters with smooth central bores for components are also available.

Thorlabs also offers Ø1" adapters for unmounted optics.

Posted Comments:
jim.guenter  (posted 2017-02-16 15:28:56.237)
Unfortunately my optic is 28 mm diameter, too large for SM1, but 2 mm too small for your smallest SM2 adapter. Any chance you have something smaller, or a blank that we could put our own hole in for the optic? Ultimately need to mate to an SM1 tube system on both sides of the lens, but we can use adapters with an SM2 section if necessary.
tfrisch  (posted 2017-02-20 09:43:16.0)
Hello, thank you for contacting Thorlabs. I will reach out to you about our Self Centering lens mounts like SCL60C. You may be able to use that with adapters to the SM1 system.
ludoangot  (posted 2016-01-29 11:54:57.927)
Your AD2-30 has the 30mm smooth bore I am looking for but no external SM2 thread. Do you have such an adapter (1.18"/ 30mm internal smooth bore and SM2 ext. thread)? Or could you please suggest a solution to mount a 30mm outer diameter objective lens into your SM2 tubes? My exact purpose is to mount said objective lens into your XY translation mount ref. CXY2.
jlow  (posted 2016-02-01 09:33:02.0)
Response from Jeremy at Thorlabs: Once the optic is mounted in the AD2-30, you can put that into a SM2 lens tube such as SM2L05, which can then be attached for the CXY2. If your optic thickness is <7.1mm, then you could also mount your optic into the SM2AD30, which can be attached to the CXY2.
f.niewoehner  (posted 2014-05-04 07:20:31.103)
Dear sir or madame, I have a question to you. Do you offer any mounts for your 2'' lens tubes to fix your square Diffraction Gratings inside of it? Thanks in advance. Sincerely, Frauke Niewöhner Friedrich-Alexander university Erlangen-Nuremberg
cdaly  (posted 2014-05-08 03:38:11.0)
Response from Chris at Thorlabs: There's no direct adapter, but a few can be used The grating can be mounted in a KGM20, KGM40, or KGM60, depending on the size. Each would then provide a 1" outer bore diameter surface which can be converted to an SM1 thread using an SM1P1 adapter and then to an SM2 thread using an SM2A6 adapter.
cbrideau  (posted 2013-04-05 14:27:36.547)
Picture caption at top of page has SM2AB2 as part number, but in list below shows it as SM2B2.
sharrell  (posted 2013-04-05 14:44:00.0)
Response from Sean at Thorlabs: Thank you for pointing out our error. We are working on fixing the caption.

Ø2" Adapters with Counterbore

Unthreaded Mounting Adapter
Click to Enlarge
Ø1" Optic Mounted in a Ø2" KM200 Mirror Mount Using an AD2 Adapter
ADx Drawing
Item # Counterbore ODa Optic Thickness (Min)b Tc
AD2 Ø1.00" (Ø25.4 mm) Ø2.00" 0.22" (5.6 mm) 0.25" (6.4 mm)
AD2-30 Ø30 mm (Ø1.18") Ø2.00" 0.22" (5.6 mm) 0.25" (6.4 mm)
AD2-1.5 Ø1.51" (Ø38 mm) Ø2.00" 0.27" (6.9 mm) 0.33" (8.4 mm)
  • Outer Diameter.
  • This specification is true for thin lenses. For lenses with short focal lengths, and hence large lens curvatures, please contact technical support to ensure a proper fit.
  • Thickness of the adapter. See the drawing above.

These unthreaded adapters feature a smooth Ø2" outer surface and a double-bored counterbore to provide two lines of mounting contact. The counterbores in the AD2, AD2-30, and AD2-1.5 are Ø1", Ø30 mm and Ø1.5", respectively. Optics are secured against the two contact lines using a nylon-tipped setscrew.

Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
AD2 Support Documentation
AD2Ø2" OD Adapter for Ø1" Optic, 0.25" Thick
AD2-30 Support Documentation
AD2-30Ø2" OD Adapter for Ø30 mm Optic, 0.25" Thick
AD2-1.5 Support Documentation
AD2-1.5Customer Inspired! Ø2" OD Adapter for Ø1.5" Optic, 0.33" Thick

Ø2" Close Approach Adapter for Ø1" Optics

Clear Aperture Adapter
Click to Enlarge

The AD2-CA Adapter Allows Separation of Closely Spaced Beams Using Ø1" Optics
AD2-CA Drawing

The AD2-CA is designed with a 2" outer diameter and dual Ø1" internal bores. Please note that only one internal bore is meant for mounting the optic, which is held in place with an 8-32 nylon-tipped setscrew. This adapter enables separation of closely spaced beams with Ø1" circular optical components and is ideal for applications that require a narrow-angle back reflection. If you wish to mount one of our D-shaped mirrors, we recommend using one of our D-shaped mirror mounts.

Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
AD2-CA Support Documentation
AD2-CAØ2" OD Adapter for Ø1" Optic with Clear Aperture, 0.28" Thick

Ø2" Adapter with Internal SM1 Threads

Threaded Mounting Adapter
Click to Enlarge

Ø1" Optic in Threaded SM1 Lens Tube Mounted in Ø2" KM200 Mirror Mount Using an AD2T Adapter
ADxT Drawing

The AD2T Adapter features internal SM1 threading and is designed to hold a Ø1" unmounted optic up to 0.37" (9.4 mm) thick with the included SM1RR retaining ring.b Alternatively, retaining rings can be used to hold this adapter in an SM2 lens tube. With a smooth outer diameter, the AD2T is especially well suited for mounting Ø1" wave plates into Ø2" mounts.

Item # CA OD Optic Thickness (Max) Internal Thread Retaining Ring Spanner Wrench
AD2T Ø23.0 mma Ø2" 0.37" (9.4 mm)b SM1 (1.035"-40) SM1RR SPW801 or SPW602
  • Clear Aperture of retaining ring.
  • Maximum Optical Thickness: This specification is true for thin lenses. For lenses with short focal lengths, and hence large lens curvatures, please contact technical support to ensure a proper fit.
Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
AD2T Support Documentation
AD2TØ2" OD Adapter with Internal SM1 Threads, 0.50" Thick

SM2-Threaded Mounting Adapters with Internal Bore

Click to Enlarge

SM1 Lens Tube Mounted in KM200 Mount Using SM2A21
SM1 Series Adapters

These adapters feature external SM2 threads and center bores through the length of each part. The SM2B2 adapter has a 0.05" hex setscrew that secures Ø1.5" objects. The SM2A21 adapter has a 5/64" (2 mm) hex nylon-tipped setscrew, secures Ø1.2" components, and also features a 2.00" (50.8 mm) outer diameter. This allows the SM2A21 to be used with Ø2" optic mounts, such as the KM200. Both mounts feature SM2 threads, allowing them to be mounted in our SM2 Lens Tubes and SM2-compatible mounts.

Item # Bore OD Optic Thickness (Max) External Thread
SM2A21 Ø1.20" (Ø30.5 mm) Ø2.00" (Ø50.8 mm) N/Aa SM2 (2.035"-40)
SM2B2 Ø1.51" (Ø38.2 mm) Ø2.20" (Ø55.9 mm) N/Aa SM2 (2.035"-40)
  • These adapters each have a center bore through the length of the part, so the thickness of the mounted object is not limited.
Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
SM2A21 Support Documentation
SM2A21Externally SM2-Threaded Mounting Adapter with Ø1.20" (Ø30.5 mm) Bore and 2" Outer Diameter
SM2B2 Support Documentation
SM2B2Externally SM2-Threaded Mounting Adapter with Ø1.51" Bore and 2.2" Outer Diameter

SM2-Threaded Mounting Adapters with Internal Threads

SM1 Series Adapters

These externally SM2-threaded adapters are designed to mount optics between Ø30 mm and Ø48 mm in internally SM2-threaded components, such as our Ø2" Lens Tubes or Ø2" Optic Mounts. Each mount features external SM2 threads and an internally threaded central bore (see the table below for thread specifications). Two retaining rings are included for securing optics in the adapter.

Item # Optic CAa Optic Thickness (Max)b Internal Thread External Thread Retaining Ring Spanner Wrench
SM2AD30 Ø30 mm Ø1.10" (Ø27.9 mm) 0.28" (7.1 mm) M30.5 x 0.5 SM2 (2.035"-40) SM30RR SPW801
SM2AD31 Ø31 mm Ø1.14" (Ø29.0 mm) 0.28" (7.1 mm) M31.5 x 0.5 SM2 (2.035"-40) SM31RR
SM2AD32 Ø32 mm Ø1.18" (Ø30.0 mm) 0.28" (7.1 mm) M32.5 x 0.5 SM2 (2.035"-40) SM32RR
SM2AD33 Ø33 mm Ø1.22" (Ø31.0 mm) 0.28" (7.1 mm) M33.5 x 0.5 SM2 (2.035"-40) SM33RR
SM2AD34 Ø34 mm Ø1.26" (Ø32.0 mm) 0.28" (7.1 mm) M34.5 x 0.5 SM2 (2.035"-40) SM34RR
SM2AD35 Ø35 mm Ø1.30" (Ø33.0 mm) 0.28" (7.1 mm) M35.5 x 0.5 SM2 (2.035"-40) SM35RR
SM2AD36 Ø36 mm Ø1.34" (Ø34.0 mm) 0.28" (7.1 mm) M36.5 x 0.5 SM2 (2.035"-40) SM36RR
SM2AD37 Ø37 mm Ø1.38" (Ø35.0 mm) 0.28" (7.1 mm) M37.5 x 0.5 SM2 (2.035"-40) SM37RR
SM2AD1.5 Ø1.5" Ø1.37" (Ø34.8 mm) 0.36" (9.1 mm) 1.535"-40 SM2 (2.035"-40) SM1.5RR SPW608 or SPW801
SM2AD39 Ø39 mm Ø1.44" (Ø36.5 mm) 0.36" (9.1 mm) M39.5 x 0.5 SM2 (2.035"-40) SM39RR SPW801
SM2AD40 Ø40 mm Ø1.47" (Ø37.5 mm) 0.36" (9.1 mm) M40.5 x 0.5 SM2 (2.035"-40) SM40RR
SM2AD41 Ø41 mm Ø1.51" (Ø38.5 mm) 0.36" (9.1 mm) M41.5 x 0.5 SM2 (2.035"-40) SM41RR
SM2AD42 Ø42 mm Ø1.55" (Ø39.5 mm) 0.36" (9.1 mm) M42.5 x 0.5 SM2 (2.035"-40) SM42RR
SM2AD43 Ø43 mm Ø1.59" (Ø40.5 mm) 0.36" (9.1 mm) M43.5 x 0.5 SM2 (2.035"-40) SM43RR
SM2AD44 Ø44 mm Ø1.63" (Ø41.5 mm) 0.36" (9.1 mm) M44.5 x 0.5 SM2 (2.035"-40) SM44RR
SM2AD45 Ø45 mm Ø1.67" (Ø42.4 mm) 0.36" (9.1 mm) M45.5 x 0.5 SM2 (2.035"-40) SM45RR
SM2AD46 Ø46 mm Ø1.71" (Ø43.5 mm) 0.36" (9.1 mm) M46.5 x 0.5 SM2 (2.035"-40) SM46RR
SM2AD47 Ø47 mm Ø1.75" (Ø44.5 mm) 0.36" (9.1 mm) M47.5 x 0.5 SM2 (2.035"-40) SM47RR
SM2AD48 Ø48 mm Ø1.79" (Ø45.5 mm) 0.36" (9.1 mm) M48.5 x 0.5 SM2 (2.035"-40) SM48RR
  • Clear Aperture of Retaining Ring.
  • Maximum Optical Thickness: This specification is true for thin lenses. For lenses with short focal lengths, and hence large lens curvatures, please contact technical support to ensure a proper fit.
Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
SM2AD30 Support Documentation
SM2AD30SM2-Threaded Mounting Adapter for Ø30 mm Optics
SM2AD31 Support Documentation
SM2AD31SM2-Threaded Mounting Adapter for Ø31 mm Optics
SM2AD32 Support Documentation
SM2AD32SM2-Threaded Mounting Adapter for Ø32 mm Optics
SM2AD33 Support Documentation
SM2AD33SM2-Threaded Mounting Adapter for Ø33 mm Optics
SM2AD34 Support Documentation
SM2AD34SM2-Threaded Mounting Adapter for Ø34 mm Optics
SM2AD35 Support Documentation
SM2AD35SM2-Threaded Mounting Adapter for Ø35 mm Optics
SM2AD36 Support Documentation
SM2AD36SM2-Threaded Mounting Adapter for Ø36 mm Optics
SM2AD37 Support Documentation
SM2AD37SM2-Threaded Mounting Adapter for Ø37 mm Optics
SM2AD1.5 Support Documentation
SM2AD1.5SM2-Threaded Mounting Adapter for Ø1.5" (Ø38 mm) Optics
SM2AD39 Support Documentation
SM2AD39SM2-Threaded Mounting Adapter for Ø39 mm Optics
SM2AD40 Support Documentation
SM2AD40SM2-Threaded Mounting Adapter for Ø40 mm Optics
SM2AD41 Support Documentation
SM2AD41SM2-Threaded Mounting Adapter for Ø41 mm Optics
SM2AD42 Support Documentation
SM2AD42SM2-Threaded Mounting Adapter for Ø42 mm Optics
SM2AD43 Support Documentation
SM2AD43SM2-Threaded Mounting Adapter for Ø43 mm Optics
SM2AD44 Support Documentation
SM2AD44SM2-Threaded Mounting Adapter for Ø44 mm Optics
SM2AD45 Support Documentation
SM2AD45SM2-Threaded Mounting Adapter for Ø45 mm Optics
SM2AD46 Support Documentation
SM2AD46SM2-Threaded Mounting Adapter for Ø46 mm Optics
SM2AD47 Support Documentation
SM2AD47SM2-Threaded Mounting Adapter for Ø47 mm Optics
SM2AD48 Support Documentation
SM2AD48SM2-Threaded Mounting Adapter for Ø48 mm Optics
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