Zinc Selenide Plano-Concave Lenses, AR Coated: 2 - 13 µm

  • AR Coating Optimized for the 2 - 13 µm Range
  • Ideal for CO2 Laser Applications Due to Low Absorption Coefficient
  • Use to Diverge Collimated Incident Light


Ø1'' Lens,

f = -200 mm


Ø1'' Lens,

f = -25.4 mm

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Common Specifications
Substrate Material Zinc Selenidea
AR Coating Range 2.0 - 13.0 μm
Reflectanceb (Per Surface) Ravg < 3.5%
Rabs < 6%
Transmissionb Tavg > 92%
Tabs > 85%
Diameter Tolerance +0.0/-0.1 mm
Thickness Tolerance ±0.1 mm
Focal Length Tolerance ±1%
Surface Quality 60-40 Scratch-Dig
Surface Powerc (Plano Side) λ/2
Spherical Surface Powerc,d (Concave Side) 3λ/2
Surface Irregularityc (Peak to Valley) λ/2
Centration <3 arcmin
Clear Aperture >Ø20.3 mm
Design Wavelength 10.6 μm
  • Click Link for Detailed Specifications on the Substrate
  • Over AR Coating Range, 0° AOI
  • At 633 nm.
  • Much like surface flatness for flat optics, spherical surface power is a measure of the deviation between the surface of the curved optic and a calibrated reference gauge, typically for a 633 nm source, unless otherwise stated. This specification is also commonly referred to as surface fit.
Zemax Files
Click on the red Document icon next to the item numbers below to access the Zemax file download. Our entire Zemax Catalog is also available.
Optic Cleaning Tutorial


  • ZnSe Substrate
  • Broadband AR Coating for the 2 - 13 μm Range
  • Focal Lengths from -25.4 mm to -200 mm Available

Thorlabs' Ø1" Zinc Selenide (ZnSe) Plano-Concave Lenses are available with a broadband AR coating optimized for the 2 µm to 13 μm spectral range deposited on both surfaces. This coating greatly reduces the high surface reflectance of the substrate, yielding an average transmission >92% across the AR coating range. See the Graphs tab for detailed information.

Like all plano-concave lenses, these lenses have negative focal lengths and can be used to diverge collimated beams; in this case, the curved surface should face the source in order to minimize spherical aberration. In addition, they can be employed to offset the effects of spherical aberration caused by other lenses in an optical system. ZnSe lenses are particularly well suited for use with high-power CO2 lasers.

This substrate scratches easily and should be handled with care. When handling optics, always wear gloves. This is especially true when working with zinc selenide, as it is a hazardous material. For your safety, please follow all proper precautions. For the MSDS for ZnSe in English, click here, and for the MSDS in Japanese, click here. Thorlabs will accept all ZnSe windows back for proper disposal. Please contact Tech Support to make arrangements for this service.

Optical Coatings and Substrates
Lens Tutorial
Selection Guide
Zinc Selenide Lenses
Other MIR Lenses
Other Spherical Singlets
AR Coated Zinc Selenide Window Transmission
Click to Enlarge

Click for Raw Data
This graph shows the measured transmission of an AR-coated zinc selenide window (Item # WG71050-E4) at normal incidence. The shaded region denotes the AR coating range, over which Tavg > 92%. Performance outside of the specified range is not guaranteed and varies from lot to lot.
AR-Coated Zinc Selenide Reflectance
Click to Enlarge

Click for Raw Data
This plot gives the measured reflectance (per surface) at an 8° angle of incidence (AOI) of our -E4 AR-coated zinc selenide substrates. The average reflectance is <3.5% per surface within the shaded wavelength range of 2.0 - 13.0 µm.
CXY1A in 30 mm Cage System
Click to Enlarge

CXY1A Translation Mount and
SM1 Lens Tube Mounted in a
30 mm Cage System
Threaded Mounting Adapter
Click to Enlarge

Ø1" Optic Mounted in a
ST1XY-S XY Translator

Click to Enlarge

LMR1 Fixed Mount with Ø1" Lens

Click to Enlarge

LM2XY Translating Mount with Ø2" Lens
Recommended Mounting Options for Thorlabs Lenses
Item # Mounts for Ø2 mm to Ø10 mm Optics
Imperial Metric
(Various) Fixed Lens Mounts and Mini-Series Fixed Lens Mounts for Small Optics, Ø5 mm to Ø10 mm
(Various) Small Optic Adapters for Use with Standard Fixed Lens Mounts, Ø2 mm to Ø10 mm
Item # Mounts for Ø1/2" (Ø12.7 mm) Optics
Imperial Metric
LMR05 LMR05/M Fixed Lens Mount for Ø1/2" Optics
MLH05 MLH05/M Mini-Series Fixed Lens Mount for Ø1/2" Optics
LM05XY LM05XY/M Translating Lens Mount for Ø1/2" Optics
SCP05 16 mm Cage System, XY Translation Mount for Ø1/2" Optics
(Various) Ø1/2" Lens Tubes,
Optional SM05RRC Retaining Ring for High-Curvature Lenses (See Below)
Item # Mounts for Ø1" (Ø25.4 mm) Optics
Imperial Metric
LMR1 LMR1/M Fixed Lens Mount for Ø1" Optics
LM1XY LM1XY/M Translating Lens Mount for Ø1" Optics
ST1XY-S ST1XY-S/M Translating Lens Mount with Micrometer Drives (Other Drives Available)
CXY1A 30 mm Cage System, XY Translation Mount for Ø1" Optics
(Various) Ø1" Lens Tubes,
Optional SM1RRC Retaining Ring for High-Curvature Lenses (See Below)
Item # Mount for Ø1.5" Optics
Imperial Metric
LMR1.5 LMR1.5/M Fixed Lens Mount for Ø1.5" Optics
(Various) Ø1.5" Lens Tubes,
Optional SM1.5RR Retaining Ring for Ø1.5" Lens Tubes and Mounts
Item # Mounts for Ø2" (Ø50.8 mm) Optics
Imperial Metric
LMR2 LMR2/M Fixed Lens Mount for Ø2" Optics
LM2XY LM2XY/M Translating Lens Mount for Ø2" Optics
CXY2 60 mm Cage System, XY Translation Mount for Ø2" Optics
(Various) Ø2" Lens Tubes,
Optional SM2RRC Retaining Ring for High-Curvature Lenses (See Below)
Item # Adjustable Optic Mounts
Imperial Metric
LH1 LH1/M Adjustable Mount for Ø0.28" (Ø7.1 mm) to Ø1.80" (Ø45.7 mm) Optics
LH2 LH2/M Adjustable Mount for Ø0.77" (Ø19.6 mm) to Ø2.28" (Ø57.9 mm) Optics
VG100 VG100/M Adjustable Clamp for Ø0.5" (Ø13 mm) to Ø3.5" (Ø89 mm) Optics
SCL03 SCL03/M Self-Centering Mount for Ø0.15" (Ø3.8 mm) to Ø1.77" (Ø45.0 mm) Optics
SCL04 SCL04/M Self-Centering Mount for Ø0.15" (Ø3.8 mm) to Ø3.00" (Ø76.2 mm) Optics
LH160C LH160C/M Adjustable Mount for 60 mm Cage Systems,
Ø0.50" (Ø13 mm) to Ø2.00" (Ø50.8 mm) Optics
SCL60C SCL60C/M Self-Centering Mount for 60 mm Cage Systems,
Ø0.15" (Ø3.8 mm) to Ø1.77" (Ø45.0 mm) Optics

Mounting High-Curvature Optics

Thorlabs' retaining rings are used to secure unmounted optics within lens tubes or optic mounts. These rings are secured in position using a compatible spanner wrench. For flat or low-curvature optics, standard retaining rings manufactured from anodized aluminum are available from Ø5 mm to Ø4". For high-curvature optics, extra-thick retaining rings are available in Ø1/2", Ø1", and Ø2" sizes.

Extra-thick retaining rings offer several features that aid in mounting high-curvature optics such as aspheric lenses, short-focal-length plano-convex lenses, and condenser lenses. As shown in the animation to the right, the guide flange of the spanner wrench will collide with the surface of high-curvature lenses when using a standard retaining ring, potentially scratching the optic. This contact also creates a gap between the spanner wrench and retaining ring, preventing the ring from tightening correctly. Extra-thick retaining rings provide the necessary clearance for the spanner wrench to secure the lens without coming into contact with the optic surface.

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Ø1" ZnSe Plano-Concave Lenses

Item # Diameter Focal Length Dioptera Radius of Curvature Center Thickness Edge Thicknessb Back Focal Length Reference
LC7759-E4 25.4 mm -25.4 mm -39.4 -35.6 mm 2.0 mm 4.3 mm -26.2 mm Plano-Concave Lens Drawing
LC7235-E4 25.4 mm -50.0 mm -20.0 -70.1 mm 2.0 mm 3.2 mm -50.8 mm
LC7421-E4 25.4 mm -75.0 mm -13.3 -105.2 mm 2.0 mm 2.8 mm -75.8 mm
LC7414-E4 25.4 mm -100.0 mm -10.0 -140.3 mm 2.0 mm 2.6 mm -100.8 mm
LC7142-E4 25.4 mm -200.0 mm -5.0 -280.5 mm 2.0 mm 2.3 mm -200.8 mm
  • Reciprocal of the Focal Length in Meters
  • Edge Thickness Value is Given Before the 0.2 mm Losses Due to Each 45° Typical Chamfer

Suggested Fixed Lens Mount: LMR1(/M)

Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
LC7759-E4 Support Documentation
LC7759-E4Ø1" ZnSe Plano-Concave Lens, f = -25.4 mm, AR-Coated: 2-13 µm
LC7235-E4 Support Documentation
LC7235-E4Ø1" ZnSe Plano-Concave Lens, f = -50 mm, AR-Coated: 2-13 µm
LC7421-E4 Support Documentation
LC7421-E4Ø1" ZnSe Plano-Concave Lens, f = -75 mm, AR-Coated: 2-13 µm
LC7414-E4 Support Documentation
LC7414-E4Ø1" ZnSe Plano-Concave Lens, f = -100 mm, AR-Coated: 2-13 µm
LC7142-E4 Support Documentation
LC7142-E4Ø1" ZnSe Plano-Concave Lens, f = -200 mm, AR-Coated: 2-13 µm