Calcium Fluoride Plano-Concave Lenses, Uncoated


  • Uncoated Lenses
  • Choose from Ø1/2" or Ø1"
  • Ideal for use with Excimer Lasers

LC5269

(Ø1")

LC5919

(Ø1/2")

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Common Specifications
Substrate Material Vacuum-Grade Calcium Fluoridea
Wavelength Range (Uncoated)b 0.18 - 8.0 μm
Diameters Available 1/2" or 1"
Diameter Tolerance +0.00/-0.10 mm
Thickness Tolerance ±0.1 mm
Focal Length Tolerance ±1%
Surface Quality 40-20 (Scratch-Dig)
Surface Flatness (Plano Side) λ/2
Spherical Surface Power
(Concave Side)c		 3λ/2
Surface Irregularity
(Peak to Valley)		 λ/2
Centration ≤3 arcmin
Clear Aperture >90% of Diameter
Design Wavelength 588 nm
  • Click Link for Detailed Specifications on the Substrate
  • These lenses are also available with an AR coating for the 2 - 5 µm range.
  • 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

Features

  • Uncoated Vacuum-Grade Calcium Fluoride Substrate
  • Ø1/2" and Ø1" Versions Available
  • Focal Lengths from -18.0 mm to -500.0 mm

Thorlabs' Ø1/2" and Ø1" Calcium Fluoride (CaF2) Plano-Concave Lenses offer high transmission from 0.18 µm to 8.0 μm. CaF2 is commonly used for applications requiring high transmission in the infrared and ultraviolet spectral ranges. Its extremely high laser damage threshold makes it useful for use with excimer lasers. The material exhibits a low refractive index, varying from 1.35 to 1.51 within its usage range of 180 nm to 8.0 μm. Calcium fluoride is also fairly chemically inert and offers superior hardness compared to its barium fluoride, magnesium fluoride, and lithium fluoride cousins.

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.

Optical Coatings and Substrates
Lens Tutorial
Selection Guide
Calcium Fluoride Lenses
Other MIR Lenses
Other Spherical Singlets
Transmission of Uncoated CaF2
Click to Enlarge
Click Here for Raw Data

Total Transmission of Optic (CaF2 Substrate, Uncoated)

The table below gives the approximate theoretical transmission of these uncoated optics for a few select wavelengths in the 0.18 - 8.0 μm range. To see an excel file that lists all measured transmission values for this wavelength range, please click here.

Wavelength (μm)Total Transmission
0.20.910
0.40.929
0.60.935
0.80.937
1.00.938
1.20.938
1.40.938
1.60.938
1.80.939
2.00.939
Wavelength
(μm)		Total Transmission
2.20.939
2.40.939
2.60.940
2.80.940
3.00.940
3.20.941
3.40.941
3.60.941
3.80.942
4.00.942
Wavelength
(μm)		Total Transmission
4.20.943
4.40.943
4.60.943
4.80.944
5.00.945
5.20.945
5.40.945
5.60.946
5.80.946
6.00.947
Wavelength
(μm)		Total Transmission
6.20.947
6.40.947
6.60.948
6.80.949
7.00.949
7.20.948
7.40.947
7.60.946
7.80.945
8.00.944

Wavelength-Dependent Focal Length Shift

The paraxial focal length of a lens is wavelength dependent. The focal length listed below for a given lens corresponds to the value at the design wavelength (i.e., the focal length at 588 nm). Since CaF2 offers high transmission from 0.18 - 8.0 µm, users may wish to use these lenses at other popular wavelengths. Click on the icons below to view theoretically-calculated focal length shifts for wavelengths within the 0.18 - 8.0 µm range.

Ø1/2" Plano-Concave Lenses

Item #LC5919LC5749
Focal Length @ 588 nm-18.0 mm-25.0 mm
Focal Length Shift
(Click for Details)
Raw Data
(Click to Download)		DataData

Ø1" Plano-Concave Lenses

Item #LC5269LC5401LC5289LC5952LC5893
Focal Length @ 588 nm-40.0 mm-75.0 mm-100.0 mm-200.0 mm-500.0 mm
Focal Length Shift
(Click for Details)
Raw Data
(Click to Download)		DataDataDataDataData
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.


Posted Comments:
user  (posted 2020-06-01 15:56:45.51)
Dear Sir/Madam Is it possible to make CaF2 Plano-Concave Lenses with UV anti-reflective coating? How much it will cost? Best regards, Pawel
YLohia  (posted 2020-06-02 09:10:32.0)
Hello Pawel, thank you for contacting Thorlabs. Custom lenses and coatings can be requested by emailing your local Thorlabs Tech Support team (techsupport.se@thorlabs.com). We will reach out to you directly.
matsuura  (posted 2016-07-06 17:38:13.217)
Laser beam size：2.0mm－φ2.5mm Pules energy:＞100μJ Pules Wide:＞50ps Wavelength :266nm Can use this Products?
tcohen  (posted 2012-03-08 14:40:00.0)
Response from Tim at Thorlabs: Thank you for your feedback. CaF2 has very low birefringence and CaF2 lenses are typically cut in a way to minimize it. I am looking into the exact orientation and will update you with the information as soon as I have it.
cfho  (posted 2012-03-07 05:16:39.0)
Dear sir Do you have the information about the crystal orientation of caf2 lens reference to the optical axis thank you very much Best regards, ho cheng-fang

Ø1/2" CaF2 Plano-Concave Lenses, Uncoated

Item # Diameter Focal Length Dioptera Radius of Curvature Center Thickness Edge Thicknessb Back Focal Lengthc Reference
Drawing
LC5919d 1/2" (12.7 mm) -18.0 mm -55.6 -7.8 mm 2.0 mm 5.3 mm -19.4 mm Plano-Concave Lens Drawing
LC5749e 1/2" (12.7 mm) -25.0 mm -40.0 -10.9 mm 2.5 mm 4.6 mm -26.7 mm
  • Reciprocal of the Focal Length in Meters
  • Edge Thickness Given Before 0.2 mm at 45° Typical Chamfer
  • Measured at the Design Wavelength, 588 nm
  • Suggested Fixed Lens Mounts: LMR05(/M) & SM05L03
  • Suggested Fixed Lens Mount: LMR05(/M)
Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
LC5919 Support Documentation
LC5919Ø1/2" CaF2 Plano-Concave Lens, f = -18.0 mm, Uncoated
$156.06
Today
LC5749 Support Documentation
LC5749Ø1/2" CaF2 Plano-Concave Lens, f = -25.0 mm, Uncoated
$145.58
7-10 Days

Ø1" CaF2 Plano-Concave Lenses, Uncoated

Item # Diameter Focal Length Dioptera Radius of Curvature Center Thickness Edge Thicknessb Back Focal Lengthc Reference
Drawing
LC5269d 1" (25.4 mm) -40.0 mm -25.0 -17.4 mm 2.0 mm 7.3 mm -41.4 mm Plano-Concave Lens Drawing
LC5401e 1" (25.4 mm) -75.0 mm -13.3 -32.5 mm 2.5 mm 5.1 mm -76.7 mm
LC5289e 1" (25.4 mm) -100.0 mm -10.0 -43.4 mm 3.0 mm 4.8 mm -102.1 mm
LC5952e 1" (25.4 mm) -200.0 mm -5.0 -86.8 mm 3.5 mm 4.5 mm -202.4 mm
LC5893e 1" (25.4 mm) -500.0 mm -2.0 -216.9 mm 4.0 mm 4.5 mm -502.8 mm
  • Reciprocal of the Focal Length in Meters
  • Edge Thickness Given Before 0.2 mm at 45° Typical Chamfer
  • Measured at the Design Wavelength, 588 nm
  • Suggested Fixed Lens Mounts: LMR1(/M) & SM1L05
  • 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
LC5269 Support Documentation
LC5269Ø1" CaF2 Plano-Concave Lens, f = -40.0 mm, Uncoated
$214.29
7-10 Days
LC5401 Support Documentation
LC5401Ø1" CaF2 Plano-Concave Lens, f = -75.0 mm, Uncoated
$202.64
Today
LC5289 Support Documentation
LC5289Ø1" CaF2 Plano-Concave Lens, f = -100.0 mm, Uncoated
$197.99
Today
LC5952 Support Documentation
LC5952Ø1" CaF2 Plano-Concave Lens, f = -200.0 mm, Uncoated
$189.84
Today
LC5893 Support Documentation
LC5893Ø1" CaF2 Plano-Concave Lens, f = -500.0 mm, Uncoated
$185.18
Today
Additional CaF2 Plano-Concave Spherical Lenses
  • CaF2, Uncoated

  • CaF2, -E Coated