Calcium Fluoride Negative Meniscus Lenses, Uncoated


  • Uncoated for 0.18 - 8 µm Transmission
  • Choose from Ø1/2" or Ø1"
  • Ideal for use with Excimer Lasers

LF5414

(Ø1")

LF5154

(Ø1/2")

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Specifications
Material Vacuum-Grade Calcium Fluoridea
Wavelength Range 0.18 - 8.0 μm
Diameter Tolerance +0.00/-0.10
Thickness Tolerance ±0.1 mm
Focal Length Tolerance ±2%
Surface Quality 40-20 Scratch-Dig
Spherical Surface Powerb 3λ/2
Spherical Surface Irregularity
(Peak to Valley)		 λ/2
Centration <3 arcmin
Clear Aperture >90% of Diameter
Design Wavelength 4 μm
  • Click Link for Detailed Specifications on the Substrate
  • 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.

Features

  • Vacuum-Grade Calcium Fluoride Substrate
  • Ø1/2" and Ø1" Versions Available
  • Uncoated for 0.18 - 8.0 µm Transmission
  • Focal Lengths from -20.0 mm to -1000.0 mm

Thorlabs' Ø1/2" and Ø1" Calcium Fluoride (CaF2) Negative Meniscus Lenses offer high transmission from 180 nm to 8.0 μm. The lenses on this page are offered uncoated, while broadband AR-coated versions for the 2 µm - 5 μm spectral range are also available.

Optic Cleaning Tutorial

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.

Negative meniscus (convex-concave) lenses, which are thinner in the middle than at the edges and cause light rays to diverge, are designed to minimize third-order spherical aberration. When used to diverge light, the convex surface should face the beam to minimize spherical aberration. They are often used in conjunction with other lenses to increase the focal length, and therefore decrease the numerical aperture (NA), of an optical assembly.

Lens Tutorial
Optical Coatings and Substrates
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
0.2 0.910
0.4 0.929
0.6 0.935
0.8 0.937
1.0 0.938
1.2 0.938
1.4 0.938
1.6 0.938
1.8 0.939
2.0 0.939
Wavelength
(μm)		 Total Transmission
2.2 0.939
2.4 0.939
2.6 0.940
2.8 0.940
3.0 0.940
3.2 0.941
3.4 0.941
3.6 0.941
3.8 0.942
4.0 0.942
Wavelength
(μm)		 Total Transmission
4.2 0.943
4.4 0.943
4.6 0.943
4.8 0.944
5.0 0.945
5.2 0.945
5.4 0.945
5.6 0.946
5.8 0.946
6.0 0.947
Wavelength
(μm)		 Total Transmission
6.2 0.947
6.4 0.947
6.6 0.948
6.8 0.949
7.0 0.949
7.2 0.948
7.4 0.947
7.6 0.946
7.8 0.945
8.0 0.944

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 4 µm). 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" Negative Meniscus Lenses

Item # LF5067 LF5847 LF5154
Focal Length @ 4 µm -20.0 mm -50.0 mm -80.0 mm
Focal Length Shift
(Click for Details)
Raw Data
(Click to Download)		 Data Data Data

Ø1" Negative Meniscus Lenses

Item # LF5469 LF5414 LF5895 LF5515 LF5175 LF5961 LF5048 LF5807 LF5394
Focal Length @ 4 µm -40.0 mm -50.0 mm -75.0 mm -100.0 mm -150.0 mm -200.0 mm -500.0 mm -750.0 mm -1000.0 mm
Focal Length Shift
(Click for Details)
Raw Data
(Click to Download)		 Data Data Data Data Data Data Data Data Data
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
LH160CA LH160CA/M Adjustable Mount for 60 mm Cage Systems,
Ø0.50" (Ø13 mm) to Ø2.00" (Ø50.8 mm) Optics
SCL60CA 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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Ø1/2" CaF2 Negative Meniscus Lenses

Item # Diameter Focal
Length		 Dioptera Radius of
Curvature 1		 Radius of
Curvature 2		 Center
Thickness		 Edge
Thicknessb		 Back Focal
Lengthc		 Reference
Drawing
LF5067d 1/2" (12.7 mm) -20.0 mm -50.0 95.6 mm 7.5 mm 2.0 mm 5.3 mm -19.9 mm Negative Meniscus Lens Drawing
LF5847e 1/2" (12.7 mm) -50.0 mm -20.0 20.4 mm 9.8 mm 3.0 mm 4.3 mm -47.9 mm
LF5154e 1/2" (12.7 mm) -80.0 mm -12.5 33.7 mm 16.2 mm 3.0 mm 3.7 mm -77.9 mm
  • Reciprocal of the Focal Length in Meters
  • Edge Thickness Given Before 0.2 mm at 45° Typical Chamfer
  • Measured at the Design Wavelength, 4 µm
  • 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
LF5067 Support Documentation
LF5067Ø1/2" CaF2 Negative Meniscus Lens, f = -20.0 mm, Uncoated
$255.41
In Stock
LF5847 Support Documentation
LF5847Ø1/2" CaF2 Negative Meniscus Lens, f = -50.0 mm, Uncoated
$255.41
In Stock
LF5154 Support Documentation
LF5154Ø1/2" CaF2 Negative Meniscus Lens, f = -80.0 mm, Uncoated
$255.41
In Stock
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Ø1" CaF2 Negative Meniscus Lenses

Item # Diameter Focal
Length		 Dioptera Radius of
Curvature 1		 Radius of
Curvature 2		 Center
Thickness		 Edge
Thicknessb		 Back Focal
Lengthc		 Reference
Drawing
LF5469d 1" (25.4 mm) -40.0 mm -25.0 308.3 mm 15.5 mm 4.0 mm 10.4 mm -39.9 mm Negative Meniscus Lens Drawing
LF5414d 1" (25.4 mm) -50.0 mm -20.0 68.5 mm 15.5 mm 4.0 mm 9.4 mm -49.2 mm
LF5895d 1" (25.4 mm) -75.0 mm -13.3 30.8 mm 14.8 mm 4.0 mm 8.5 mm -72.2 mm
LF5515e 1" (25.4 mm) -100.0 mm -10.0 42.0 mm 20.2 mm 4.0 mm 6.5 mm -97.2 mm
LF5175e 1" (25.4 mm) -150.0 mm -6.7 64.1 mm 30.8 mm 4.0 mm 5.5 mm -147.3 mm
LF5961e 1" (25.4 mm) -200.0 mm -5.0 86.2 mm 41.4 mm 4.0 mm 5.1 mm -197.3 mm
LF5048e 1" (25.4 mm) -500.0 mm -2.0 218.3 mm 105.1 mm 4.0 mm 4.4 mm -497.3 mm
LF5807e 1" (25.4 mm) -750.0 mm -1.3 328.2 mm 158.1 mm 4.0 mm 4.3 mm -747.3 mm
LF5394e 1" (25.4 mm) -1000.0 mm -1.0 438.1 mm 211.1 mm 4.0 mm 4.2 mm -997.4 mm
  • Reciprocal of the Focal Length in Meters
  • Edge Thickness Given Before 0.2 mm at 45° Typical Chamfer
  • Measured at the Design Wavelength, 4 µm
  • 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
LF5469 Support Documentation
LF5469Ø1" CaF2 Negative Meniscus Lens, f = -40.0 mm, Uncoated
$339.74
In Stock
LF5414 Support Documentation
LF5414Ø1" CaF2 Negative Meniscus Lens, f = -50.0 mm, Uncoated
$339.74
In Stock
LF5895 Support Documentation
LF5895Ø1" CaF2 Negative Meniscus Lens, f = -75.0 mm, Uncoated
$339.74
In Stock
LF5515 Support Documentation
LF5515Ø1" CaF2 Neg.tive Meniscus Lens, f = -100.0 mm, Uncoated
$339.74
In Stock
LF5175 Support Documentation
LF5175Ø1" CaF2 Negative Meniscus Lens, f = -150.0 mm, Uncoated
$339.74
Lead Time
LF5961 Support Documentation
LF5961Ø1" CaF2 Negative Meniscus Lens, f = -200.0 mm, Uncoated
$339.74
Lead Time
LF5048 Support Documentation
LF5048Ø1" CaF2 Negative Meniscus Lens, f = -500.0 mm, Uncoated
$339.74
In Stock
LF5807 Support Documentation
LF5807Ø1" CaF2 Negative Meniscus Lens, f = -750.0 mm, Uncoated
$339.74
In Stock
LF5394 Support Documentation
LF5394Ø1" CaF2 Negative Meniscus Lens, f = -1000.0 mm, Uncoated
$339.74
In Stock
Additional Negative Meniscus Lenses
  • N-BK7

  • UV Fused Silica

  • CaF2, Uncoated

  • CaF2, AR Coated

  • ZnSe

  • Spherical Singlets Lens Kits