Features

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

Thorlabs' Ø1/2" and Ø1" Calcium Fluoride (CaF₂) Plano-Convex Lenses, which offer high transmission from 0.18 - 8.0 μm, are available uncoated. See the Graphs tab for detailed information about the transmission of CaF₂.

Coated CaF₂ Plano-Convex Lenses are also available, which are coated for either the 1.8 - 2.4 µm or 3 - 5 µm wavelength range.

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.

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.

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.

Wavelength-Dependent Focal Length Shift
The paraxial focal length of a lens is wavelength dependent. The focal length listed under the Specs tab 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. Below is a table that gives the focal length (in millimeters) for each lens at fifteen popular wavelengths within the 0.18 - 8.0 μm range.

The first column lists the fifteen wavelengths for which the focal length was calculated. The first row lists the item numbers. Trace across the row of choice to the column of choice to find the focal length corresponding to that lens and that wavelength. For example, the focal length of an LA5458 plano-convex lens at 488 nm is 79.44 mm. Note that the row denoting the focal lengths at the design wavelength is highlighted in orange.

Ø1/2" Plano-Convex Lenses

	LA5315	LA5183	LA5458
248 nm	18.52 mm	46.34 mm	74.16 mm
405 nm	19.64 mm	49.13 mm	78.62 mm
488 nm	19.84 mm	49.64 mm	79.44 mm
532 nm	19.91 mm	49.82 mm	79.73 mm
588 nm	19.98 mm	49.99 mm	80.00 mm
633 nm	20.03 mm	50.11 mm	80.18 mm
780 nm	20.13 mm	50.35 mm	80.58 mm
850 nm	20.16 mm	50.44 mm	80.71 mm
1064 nm	20.23 mm	50.62 mm	81.01 mm
1310 nm	20.30 mm	50.78 mm	81.26 mm
1550 nm	20.35 mm	50.91 mm	81.47 mm
3000 nm	20.75 mm	51.91 mm	83.07 mm
4000 nm	21.16 mm	52.95 mm	84.73 mm
5000 nm	21.73 mm	54.37 mm	87.00 mm
8000 nm	24.78 mm	62.00 mm	99.22 mm

Ø1" Plano-Convex Lenses

	LA5370	LA5763	LA5042	LA5817	LA5012
248 nm	37.07 mm	46.34 mm	69.53 mm	92.69 mm	139.05 mm
405 nm	39.30 mm	49.13 mm	73.71 mm	98.26 mm	147.41 mm
488 nm	39.71 mm	49.64 mm	74.47 mm	99.28 mm	148.94 mm
532 nm	39.85 mm	49.82 mm	74.74 mm	99.64 mm	149.48 mm
588 nm	39.99 mm	49.99 mm	75.00 mm	99.99 mm	150.01 mm
633 nm	40.08 mm	50.11 mm	75.17 mm	100.21 mm	150.34 mm
780 nm	40.28 mm	50.35 mm	75.54 mm	100.71 mm	151.09 mm
850 nm	40.34 mm	50.44 mm	75.67 mm	100.87 mm	151.33 mm
1064 nm	40.49 mm	50.62 mm	75.94 mm	101.24 mm	151.89 mm
1310 nm	40.62 mm	50.78 mm	76.18 mm	101.55 mm	152.35 mm
1550 nm	40.73 mm	50.91 mm	76.38 mm	101.83 mm	152.76 mm
3000 nm	41.52 mm	51.91 mm	77.87 mm	103.82 mm	155.75 mm
4000 nm	42.35 mm	52.95 mm	79.44 mm	105.90 mm	158.87 mm
5000 nm	43.49 mm	54.37 mm	81.56 mm	108.73 mm	163.12 mm
8000 nm	49.59 mm	62.00 mm	93.01 mm	124.00 mm	186.03 mm

	LA5714	LA5255	LA5464	LA5956	LA5835
248 nm	185.39 mm	231.76 mm	463.51 mm	695.27 mm	927.03 mm
405 nm	196.54 mm	245.69 mm	491.39 mm	737.08 mm	982.78 mm
488 nm	198.58 mm	248.24 mm	496.49 mm	744.73 mm	992.98 mm
532 nm	199.30 mm	249.15 mm	498.29 mm	747.44 mm	996.58 mm
588 nm	200.00 mm	250.02 mm	500.04 mm	750.05 mm	1000.07 mm
633 nm	200.45 mm	250.58 mm	501.15 mm	751.73 mm	1002.30 mm
780 nm	201.44 mm	251.82 mm	503.64 mm	755.46 mm	1007.28 mm
850 nm	201.77 mm	252.23 mm	504.46 mm	756.69 mm	1008.93 mm
1064 nm	202.51 mm	253.15 mm	506.30 mm	759.46 mm	1012.61 mm
1310 nm	203.13 mm	253.93 mm	507.86 mm	761.80 mm	1015.73 mm
1550 nm	203.67 mm	254.61 mm	509.22 mm	763.83 mm	1018.44 mm
3000 nm	207.66 mm	259.59 mm	519.18 mm	778.77 mm	1038.36 mm
4000 nm	211.82 mm	264.79 mm	529.59 mm	794.38 mm	1059.17 mm
5000 nm	217.49 mm	271.88 mm	543.77 mm	815.65 mm	1087.53 mm
8000 nm	248.03 mm	310.06 mm	620.11 mm	930.17 mm	1240.22 mm