Products Home / Optical Elements / Optical Lenses / Spherical Singlet Lenses / Plano-Concave Spherical Lenses / CaF2 Plano-Concave Spherical Lenses / Calcium Fluoride Plano-Concave Lenses, AR-Coated: 2 - 5 µmCalcium Fluoride Plano-Concave Lenses, AR-Coated: 2 - 5 µm
- Broadband AR Coating Optimized for the 2 - 5 µm Range
- Choose from Ø1/2" or Ø1"
LC5269-E1
(Ø1")
LC5919-E1
(Ø1/2")
Please Wait
| Common Specifications | |
|---|---|
| Substrate Material | Vacuum-Grade Calcium Fluoridea |
| AR Coating Range | 2 - 5 µm |
| Reflectance over Coating Rangeb | Avg <1.25%, Abs <3.0% |
| Transmission over Coating Rangeb | Avg >94%, Abs >90% |
| Diameters Available | 1/2" or 1" |
| Diameter Tolerance | +0.0/-0.1 mm |
| Thickness Tolerance | ±0.1 mm |
| Focal Length Tolerance | ±1% |
| Surface Quality | 40-20 Scratch-Dig |
| Surface Flatness (Plano Side)c |
λ/2 |
| Spherical Surface Power (Concave Side)c,d |
3λ/2 |
| Surface Irregularity (Peak to Valley)c |
λ/2 |
| Centration | <3 arcmin |
| Clear Aperture | >90% of Diameter |
| Design Wavelength | 588 nm |
 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
- Broadband AR Coating for the 2 - 5 μm Range
- Focal Lengths from -18.0 mm to -500.0 mm
Thorlabs' Ø1/2" and Ø1" Calcium Fluoride (CaF2) Plano-Concave Lenses have a broadband AR coating optimized for the 2 µm to 5 μm spectral range deposited on both surfaces. This coating greatly reduces the surface reflectivity of the substrate, yielding an average transmission in excess of 94% over the entire AR coating range. See the Graphs tab for detailed information.
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.
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.
Lens Coloration May VaryDue to variations in the coating process, lenses on this page may vary in color. All lenses meet or exceed the listed specifications.
See the tables below for individual lens specifications. These lenses are also available uncoated.
| Selection Guide |
|---|
| Calcium Fluoride Lenses |
| Other MIR Lenses |
| Other Spherical Singlets |
2 - 5 µm AR Coating Graphs
Click to Enlarge
Click Here for Raw Data
Shown above is a graph of the measured percent reflectance of an -E1 AR coated CaF2 substrate as a function of wavelength at 0° AOI. 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.
Click to Enlarge
Click Here for Raw Data
Shown above is a graph of the measured percent transmission of an -E1 AR coated, 5 mm thick CaF2 substrate as a function of wavelength at 0° AOI. 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 Graph
Click to Enlarge
Click Here for Raw Data
Shown above is a graph of the measured transmission of an uncoated, 5 mm thick sample of CaF2 at 0° AOI.
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.
| 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 |
| 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.
| Posted Comments: | |
hai wang
(posted 2023-05-28 12:49:13.653) Excuse me, may i know the damage threshold of these concave lenses (-E)?
Thank you! cdolbashian
(posted 2023-06-12 10:02:22.0) Thank you for reaching out to us with this inquiry, at the time of posting this, we have not done official LIDT testing for this coating on these optics, so we do not have an official value to share. I have contacted you directly in order to determine if your specific laser would be compatible with our lens. mchen
(posted 2016-08-05 10:45:26.937) Hi,
We need LC5919 and LC5749 with D AR coating. Can you provide that?
Thanks,
Mike kucirek
(posted 2013-08-15 17:07:34.86) Do you offer or plan to offer concave spherical lenses AR-coated for 1.8-2.4µm as you do for plano-convex lenses ? tcohen
(posted 2013-08-22 14:56:00.0) Response from Tim at Thorlabs: Thank you for your feedback. We hadn’t had a formal plan for this but we are looking at it based on your inquiry. We can often do customs and in the meantime, we should be able to offer it for you this way. I will contact you to discuss this further. |
| Item # | Diameter | Focal Lengtha | Diopterb | Radius of Curvature | Center Thickness | Edge Thicknessc | Back Focal Lengtha | Reference Drawing |
|---|---|---|---|---|---|---|---|---|
| LC5919-E1d | 1/2" (12.7 mm) | -18.0 mm | -55.6 | -7.8 mm | 2.0 mm | 5.3 mm | -19.4 mm |  |
| LC5749-E1e | 1/2" (12.7 mm) | -25.0 mm | -40.0 | -10.8 mm | 2.5 mm | 4.6 mm | -26.7 mm |
| Item # | Diameter | Focal Lengtha | Diopterb | Radius of Curvature | Center Thickness | Edge Thicknessc | Back Focal Lengtha | Reference Drawing |
|---|---|---|---|---|---|---|---|---|
| LC5269-E1d | 1" (25.4 mm) | -40.0 mm | -25.0 | -17.4 mm | 2.0 mm | 7.5 mm | -41.4 mm | |
| LC5401-E1e | 1" (25.4 mm) | -75.0 mm | -13.3 | -32.5 mm | 2.5 mm | 5.1 mm | -76.8 mm | |
| LC5289-E1e | 1" (25.4 mm) | -100.0 mm | -10.0 | -43.4 mm | 3.0 mm | 4.9 mm | -102.1 mm | |
| LC5952-E1e | 1" (25.4 mm) | -200.0 mm | -5.0 | -86.8 mm | 3.5 mm | 4.4 mm | -202.4 mm | |
| LC5893-E1e | 1" (25.4 mm) | -500.0 mm | -2.0 | -216.9 mm | 4.0 mm | 4.4 mm | -502.8 mm |
 CaF2, -E1 Coated |