Calcium Fluoride Plano-Convex Lenses, AR Coated: 2 - 5 µm


  • AR Coating Optimized for the 2 - 5 µm Range
  • Choose from Ø1/2" or Ø1"

LA5315-E

(Ø1/2")

LA5370-E

(Ø1")

LA5458-E

(Ø1/2")

LA5255-E

(Ø1")

Related Items


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Key Specifications
Substrate Material Vacuum-Grade Calcium Fluoridea
AR Coating Range 2 - 5 μm
Reflectance over Coating Range (Avg.) <1.25%
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 Powerb
(Convex Side)
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
  • 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

  • Vacuum-Grade Calcium Fluoride Substrate
  • Ø1/2" and Ø1" Versions Available
  • Broadband AR Coating for the 2 - 5 μm Range
  • Focal Lengths from 20.0 mm to 1000.0 mm

Thorlabs' Ø1/2" and Ø1" Calcium Fluoride (CaF2) Plano-Convex Lenses are available with a broadband AR coating optimized for the 2 µm to 5 µm spectral range deposited on both surfaces. This coating greatly reduces the surface reflectance of the substrate, yielding an average transmission in excess of 95% over the entire AR coating range. See the Graphs tab for detailed information.

Thorlabs also offers Uncoated CaF2 Plano-Convex Lenses, which can be used over the range of 0.18 µm to 8 µm, and D-Coated CaF2 Plano-Convex Lenses, which have a broadband AR coating for the 1.65 µm to 3.0 µm range.

CaF2 is commonly used for applications requiring high transmission in the infrared and ultraviolet spectral ranges. 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.

Plano-Convex lenses have a positive focal length and approach best form for infinite and finite conjugate applications. Please click here for details concerning Best Form Lenses. These lenses focus a collimated beam to the back focus and collimate light from a point source. They are designed with minimal spherical aberration and have a focal length which can be calculated using a simplified thick lens equation:

f= R/(n-1),

where n is the index of refraction and R is the radius of curvature of the lens surface.

Optical Coatings and Substrates
Lens Tutorial

Usage:
To minimize the introduction of spherical aberrations, light should be bent gradually as it propagates through the lens. Therefore, when using a plano-convex lens to focus a collimated light source, the collimated light should be incident on the curved surface. Similarly, when collimating a point source of light, the diverging light rays should be incident on the planar surface of the lens.

Selection Guide
Calcium Fluoride Lenses
Other MIR Lenses
Other Spherical Singlets

2 - 5 µm AR Coating Graphs

CaF2 -E Reflectance
Click to Enlarge

Click Here for an Excel File with Plot Data
Shown above is a graph of the measured percent reflectance of the enhanced AR coating as a function of wavelength. The average reflectance in the 2 - 5 μm range is <1.25%. The blue shading indicates the region for which the AR coating is optmized. Performance outside of the specified range is not guaranteed and varies from lot to lot. The excel file above provides the coating curve data over an extended wavelength range.
CaF2 Transmission 3 to 5 micron antireflective coating
Click to Enlarge

Click Here for an Excel File with Plot Data
Shown above is a graph of the measured percent transmission of the enhanced AR coating as a function of wavelength. The blue shading indicates the region for which the AR coating is optmized. Performance outside of the specified range is not guaranteed and varies from lot to lot. The excel file above provides the coating curve data over an extended wavelength range.

CaF2 Transmission

CaF2 Uncoated Transmission
Click to Enlarge

Click Here for an Excel File with Plot Data
Shown above is a graph of the measured transmission of an uncoated, 5 mm thick sample of CaF2.

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.

The blue shading indicates the region for which the AR coating is optimized. Please see the Graphs tab for more information.

Ø1/2" Plano-Convex Lenses

Item # LA5315-E LA5183-E LA5458-E
Focal Length @ 588 nm 20.0 mm 50.0 mm 80.0 mm
Focal Length Shift
(Click for Details)
Raw Data
(Click to Download)
Data Data Data

Ø1" Plano-Convex Lenses

Item # LA5370-E LA5763-E LA5042-E LA5817-E LA5012-E LA5714-E LA5255-E LA5464-E LA5956-E LA5835-E
Focal Length @ 588 nm 40.0 mm 50.0 mm 75.0 mm 100.0 mm 150.0 mm 200.0 mm 250.0 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 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
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:
Alexander Novikov  (posted 2024-01-17 11:05:07.877)
Hi, It is written that the focal length for a 1-inch CaF2 lens is 100 mm, and it is measured at a wavelength of 588 nm. What is the focal length for 4 µm? Thank you.
jdelia  (posted 2024-01-17 01:16:58.0)
Thank you for contacting Thorlabs. You can find our data for focal length shift of our Calcium Fluoride plan-convex lenses here: www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=6757&tabname=FocalLengthShift. Looking at the data for LA5817-E, we specify a focal length shift of about +5.9 mm at 4 um, which corresponds to a focal length of ~105.9 mm.
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Ø1/2" CaF2 Plano-Convex Lenses, AR-Coated: 2 - 5 µm

Item # Diameter Focal Length Dioptera Radius of Curvature Center Thickness Edge Thicknessb Back Focal Lengthc Reference
Drawing
LA5315-E 1/2" (12.7 mm) 20.0 mm +50.0 8.7 mm 4.3 mm 1.5 mm 17.0 mm Plano-Convex Lens Drawing
LA5183-E 1/2" (12.7 mm) 50.0 mm +20.0 21.7 mm 2.5 mm 1.5 mm 48.3 mm
LA5458-E 1/2" (12.7 mm) 80.0 mm +12.5 34.7 mm 2.1 mm 1.5 mm 78.5 mm

Suggested Fixed Lens Mount: LMR05(/M)

  • 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.
Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
LA5315-E Support Documentation
LA5315-E Ø1/2" CaF2 Plano-Convex Lens, f = 20 mm, AR-Coated: 2 - 5 µm
$155.62
Today
LA5183-E Support Documentation
LA5183-E Ø1/2" CaF2 Plano-Convex Lens, f = 50 mm, AR-Coated: 2 - 5 µm
$158.00
Today
LA5458-E Support Documentation
LA5458-E Ø1/2" CaF2 Plano-Convex Lens, f = 80 mm, AR-Coated: 2 - 5 µm
$146.12
Today
Back to Top

Ø1" CaF2 Plano-Convex Lenses, AR-Coated: 2 - 5 µm

Item # Diameter Focal Length Dioptera Radius of Curvature Center Thickness Edge Thicknessb Back Focal Lengthc Reference
Drawing
LA5370-E 1" (25.4 mm) 40.0 mm +25.0 17.4 mm 7.5 mm 2.0 mm 34.7 mm Plano-Convex Lens Drawing
LA5763-E 1" (25.4 mm) 50.0 mm +20.0 21.7 mm 6.1 mm 2.0 mm 45.7 mm
LA5042-E 1" (25.4 mm) 75.0 mm +13.3 32.5 mm 4.6 mm 2.0 mm 71.8 mm
LA5817-E 1" (25.4 mm) 100.0 mm +10.0 43.4 mm 3.9 mm 2.0 mm 97.3 mm
LA5012-E 1" (25.4 mm) 150.0 mm +6.7 65.1 mm 3.3 mm 2.0 mm 147.7 mm
LA5714-E 1" (25.4 mm) 200.0 mm +5.0 86.8 mm 2.9 mm 2.0 mm 198.0 mm
LA5255-E 1" (25.4 mm) 250.0 mm +4.0 108.5 mm 2.7 mm 2.0 mm 248.1 mm
LA5464-E 1" (25.4 mm) 500.0 mm +2.0 216.9 mm 2.4 mm 2.0 mm 498.3 mm
LA5956-E 1" (25.4 mm) 750.1 mm +1.3 325.4 mm 2.2 mm 2.0 mm 748.5 mm
LA5835-E 1" (25.4 mm) 1000.0 mm +1.0 433.9 mm 2.2 mm 2.0 mm 998.6 mm

Suggested Fixed Lens Mount: LMR1(/M)

  • 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.
Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
LA5370-E Support Documentation
LA5370-E Ø1" CaF2 Plano-Convex Lens, f = 40 mm, AR-Coated: 2 - 5 µm
$212.64
Today
LA5763-E Support Documentation
LA5763-E Ø1" CaF2 Plano-Convex Lens, f = 50 mm, AR-Coated: 2 - 5 µm
$224.51
Today
LA5042-E Support Documentation
LA5042-E Ø1" CaF2 Plano-Convex Lens, f = 75 mm, AR-Coated: 2 - 5 µm
$261.33
Today
LA5817-E Support Documentation
LA5817-E Ø1" CaF2 Plano-Convex Lens, f = 100 mm, AR-Coated: 2 - 5 µm
$148.49
Today
LA5012-E Support Documentation
LA5012-E Ø1" CaF2 Plano-Convex Lens, f = 150 mm, AR-Coated: 2 - 5 µm
$160.36
Today
LA5714-E Support Documentation
LA5714-E Ø1" CaF2 Plano-Convex Lens, f = 200 mm, AR-Coated: 2 - 5 µm
$161.56
Today
LA5255-E Support Documentation
LA5255-E Ø1" CaF2 Plano-Convex Lens, f = 250 mm, AR-Coated: 2 - 5 µm
$186.51
Today
LA5464-E Support Documentation
LA5464-E Ø1" CaF2 Plano-Convex Lens, f = 500 mm, AR-Coated: 2 - 5 µm
$154.44
Today
LA5956-E Support Documentation
LA5956-E Ø1" CaF2 Plano-Convex Lens, f = 750 mm, AR-Coated: 2 - 5 µm
$160.36
Today
LA5835-E Support Documentation
LA5835-E Ø1" CaF2 Plano-Convex Lens, f = 1000 mm, AR-Coated: 2 - 5 µm
$158.00
Today