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Molded Glass Aspheric Lenses: 600 - 1050 nm or 650 - 1050 nm Broadband AR Coating
Aspheric lenses focus or collimate light without introducing spherical aberration into the transmitted wavefront. For monochromatic sources, spherical aberration often prevents a single spherical lens from achieving diffraction-limited performance when focusing or collimating light. Thus, an aspheric lens is often the best single element solution for many applications including collimating the output of a fiber or laser diode, coupling light into a fiber, spatial filtering, or imaging light onto a detector.
All molded glass aspheres are also available premounted in non-magnetic 303 stainless steel lens cells that are engraved with the part number for easy identification. These mounted aspheres have a metric thread that makes them easy to integrate into an optical setup or OEM application. The mounted aspheres are readily adapted to our SM1 series of lens tubes by using our Aspheric Lens Adapters. Mounted aspheres can be used as a drop-in replacement for multi-element microscope objective by combining the lens with our Microscope Objective Adapter Extension Tube.
If an unmounted aspheric lens is being used to collimate the light from a point source or laser diode, the side with the greater radius of curvature (i.e., the flatter surface) should face the point source or laser diode. To collimate light using one of our mounted aspheric lenses, orient the housing so that the externally threaded end of the mount faces the source.
Molded glass aspheres are manufactured from a variety of optical glasses to yield the indicated performance. The molding process will cause the properties of the glass (e.g., Abbe number) to deviate slightly from those given by glass manufacturers. Specific material properties for each lens can be found by clicking on the Glass link in the tables below.
Webpage Features
Click to view complete specifications, documents, and drawings.
Performance Hyperlink
Click to view item specific spot diagrams at various wavelengths and focal length shift data.
Choosing a Lens
Aspheric lenses are commonly chosen to couple incident light with a diameter of 1 - 5 mm into a single mode fiber. A simple example will illustrate the key specifications to consider when trying to choose the correct lens.
Example: Fiber: P1-630A-FC-2 Collimated Beam Diameter Prior to Lens: Ø3 mm
The specifications for the P1-630A-FC-2, 630 nm, FC single mode patch cable indicate that the mode field diameter (MFD) is 4.3 μm. This specification should be matched to the diffraction-limited spot size given by the following equation:
Here, f is the focal length of the lens, λ is the wavelength of the input light, and D is the diameter of collimated beam incident on the lens. Solving for the desired focal length of the collimating lens yields
Thorlabs offers a large selection of mounted and unmounted aspheric lenses to choose from. The aspheric lens with a focal length that is closest to 16 mm has a focal length of 15.29 mm (Item# 352260-B or A260-B). This lens also has a clear aperture that is larger than the collimated beam diameter. Therefore, this aspheric lens is the best option given the initial parameters (i.e., a P1-630A-FC-2 single mode fiber and a collimated beam diameter of 3 mm). Remember, for optimum coupling the spot size of the focused beam must be less than the MFD of the single mode fiber. As a result, if an aspheric lens is not available that provides an exact match, then choose the aspheric lens with a focal length that is shorter than the calculation above yields. Alternatively, if the clear aperture of the aspheric lens is large enough, the beam can be expanded before the aspheric lens, which has the result of reducing the spot size of the focus beam.
Lens Design Formula
Positive Radius Indicates that the Vertex is Located Left of the Center
Negative Radius Indicates that the Vertex is Located Right of the Center
Variable Definitions
z
SAG as a Function of Y
R
Radius of Curvature
k
Conic Constant
A4
4th Order Aspheric Coefficient
A6
6th Order Aspheric Coefficient
A8
8th Order Aspheric Coefficient
A10
10th Order Aspheric Coefficient
A12
12th Order Aspheric Coefficient
A14
14th Order Aspheric Coefficient
A16
16th Order Aspheric Coefficient
Aspheric Lens Coefficients
The aspheric lens coefficients are listed on the lens information pages that are loaded by clicking on the symbol in the tables below and in the .pdf and .dxf files available for each lens. Links to the files can be found under the Drawings and Documents tab or by clicking on the part number in the price table below.
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Posted Comments:
Poster:
Posted Date: 2012-10-01 15:40:57.0
Confusion! 600nm- or 650nm- starting wavelength of AR coating????
Poster: dgardner
Posted Date: 2012-10-01 15:34:00.0
A response from Dave at Thorlabs: Thank you for your feedback. The lenses sold on this page are coated for either 600 - 1050 nm or 650 - 1050 nm. We have updated the specs tables to include the correct AR coating range for each individual lens.
Poster: jlow
Posted Date: 2012-07-31 14:03:00.0
A response from Jeremy at Thorlabs: Thank you for your feedback. The reason the M12 threading is used is because of the size of the unmounted lens, which is about 9.94mm in diameter. With regard to adapters, we only have adapters to SM1 or RMS threading. The reason we do not have an M12 adapter for SM05 is because the wall of the adapter would then be too thin. I will contact you directly with regard to other alternative.
Poster: paul.lauria
Posted Date: 2012-07-30 19:32:07.0
I should say, your *half-inch* lens tubes don't have an adapter for the M12x0.5. Why...? We're kind of tight on space is why I ask.
Poster: paul.lauria
Posted Date: 2012-07-30 19:23:22.0
Your lens tubes don't have adapters for M12 x 0.5 threads, so why bother using this thread for your EFL=8mm lens'? is there some alternative? I'd like to use one of the M8 and M12 lens on this page in a tube. (specifically, C240TME-B and C390TME-B)
Poster: jlow
Posted Date: 2012-07-30 13:20:00.0
Response from Jeremy at Thorlabs. The drop in refractive index is a result of the molding process used in making these molded aspheres. The aspheres are molded above the glass transition temperature and cooled rapidly. This results in a small amount of residual stress, which translates into a small index drop. This data can be found in the Zemax catalogs.
Poster: clarafly
Posted Date: 2012-07-28 03:21:47.0
The index of H-LAK54 at 655 nm is 1.724 in the autocad pdf of A390-B, but http://refractiveindex.info/?group=CDGM&material=H-LAK54 and CDGM's database both give 1.72975 at 655 nm, why the difference? Can you provide your version of dispersion formula?
Poster: bdada
Posted Date: 2012-02-24 15:07:00.0
Response from Buki at Thorlabs to acable:
Thank you for your feedback. The variable holds the units but the coefficients are unitless. We are currently looking into how best to unify the information in one document.
Poster: bdada
Posted Date: 2012-01-23 08:50:00.0
Response from Buki at Thorlabs:
Thank you for your feedback. The housings of our mounted aspheric lenses are made from 303 stainless steel, which should be non magnetic. We can provide custom aluminum housings and have contacted you to get more information.
Poster: p.nowik
Posted Date: 2012-01-19 11:06:41.0
Is there a possibility to get the lenses mounted in non magnetic materials, for example aluminium?
Poster: acable
Posted Date: 2012-01-13 18:47:21.0
Do the aspheric coeficients have units, seem to be missing from your drawings.
It would be nice if the pdf "Spot Diagrams for Laser Quality Molded Glass Aspheric Lens 352230" had the drawing embedded in it so we don't have to open multiple documents.
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