Focus or Collimate Light Without Introducing Spherical Aberration
Available Unmounted or Pre-Mounted in Nonmagnetic 303 Stainless Steel Lens Cells Engraved with the Item #
Broadband AR Coating for Either 350 - 700 nm or 400 - 600 nm
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. Aspheric lenses are designed to mitigate the impacts of spherical aberration and are 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 of the molded glass lenses featured on this page are available with an antireflection coating for either the 350 - 700 nm or 400 - 600 nm range deposited on both sides. Other AR coating options are listed in the Aspheric Lens Selection Guide table at right.
These lenses can be purchased unmounted or premounted in nonmagnetic 303 stainless steel lens cells that are engraved with the Item # for easy identification. All mounted aspheres have a metric thread that make them easy to integrate into an optical setup or OEM application; they can also be readily used with our SM1-threaded (1.035"-40) lens tubes by using our aspheric lens adapters. When combined with our microscope objective adapter extension tube, mounted aspheres can be used as a drop-in replacement for multi-element microscope objectives.
A selection of the lenses sold on this page are designed for collimating laser diodes. As seen in the tables below, a compatible laser window thickness is listed for these lenses. In these instances, the numerical aperture (NA), working distance (WD), and wavefront error of these lenses are defined based on the presence of a laser window of the indicated thickness (not included).
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 Info Icon in the tables below and selecting the Glass tab.
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/PC 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 # 354260-B or A260-B). This lens also has a clear aperture that is larger than the collimated beam diameter. Therefore, this option is the best choice given the initial parameters (i.e., a P1-630A-FC-2 single mode fiber and a collimated beam diameter of 3 mm). Remember, for optimal 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 one 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.
The target values of these constants are available by clicking on the Info Icons () below or by viewing the .pdf and .dxf files available for each lens. Links to the files can be found by clicking on the part number in the price tables below.
Aspheric Lens Design Formula
Positive Radius Indicates that the Center of Curvature is to the Right of the Lens
Negative Radius Indicates that the Center of Curvature is to the Left of the Lens
Aspheric Lens Equation
Choosing a Collimation Lens for Your Laser Diode
Since the output of a laser diode is highly divergent, collimating optics are necessary. Aspheric lenses do not introduce spherical aberration and are therefore are commonly chosen when the collimated laser beam is to be between one and five millimeters. A simple example will illustrate the key specifications to consider when choosing the correct lens for a given application.
Example
Laser Diode to be Used: L780P010
Desired Collimated Beam Diameter: Ø3 mm (Major Axis)
When choosing a collimation lens, it is essential to know the divergence angle of the source being used and the desired output diameter. The specifications for the L780P010 laser diode indicate that the typical parallel and perpendicular FWHM beam divergences are 10° and 30°, respectively. Therefore, as the light diverges, an elliptical beam will result. To collect as much light as possible during the collimation process, consider the larger of these two divergence angles in any calculations (i.e., in this case, use 30°). If you wish to convert your elliptical beam into a round one, we suggest using an Anamorphic Prism Pair, which magnifies one axis of your beam.
Ø = Beam Diameter
Θ = Divergence Angle
Assuming that the width of the lens is negligible compared to the radius of curvature, the thin lens approximation can be used to determine the appropriate focal length for the asphere. Assuming a divergence angle of 30° (FWHM) and desired beam diameter of 3 mm:
f = Focal Length
Note that the focal length is generally not equal to the needed distance between the light source and the lens.
With this information known, it is now time to choose the appropriate collimating lens. Thorlabs offers a large selection of aspheric lenses. For this application, the ideal lens is a molded glass aspheric lens with focal length near 5.6 mm and our -B antireflection coating, which covers 780 nm. The C171TMD-B (mounted) or 354171-B (unmounted) aspheric lenses have a focal length of 6.20 mm, which will result in a collimated beam diameter (major axis) of 3.3 mm. Next, check to see if the numerical aperture (NA) of the diode is smaller than the NA of the lens:
0.30 = NALens > NADiode ≈ sin(15°) = 0.26
Up to this point, we have been using the full-width at half maximum (FWHM) beam diameter to characterize the beam. However, a better practice is to use the 1/e2 beam diameter. For a Gaussian beam profile, the 1/e2 diameter is almost equal to 1.7X the FWHM diameter. The 1/e2 beam diameter therefore captures more of the laser diode's output light (for greater power delivery) and minimizes far-field diffraction (by clipping less of the incident light).
A good rule of thumb is to pick a lens with an NA twice that of the laser diode NA. For example, either the A390-B or the A390TM-B could be used as these lenses each have an NA of 0.53, which is more than twice the approximate NA of our laser diode (0.26). These lenses each have a focal length of 4.6 mm, resulting in an approximate major beam diameter of 2.5 mm. In general, using a collimating lens with a short focal length will result in a small collimated beam diameter and a large beam divergence, while a lens with a large focal length will result in a large collimated beam diameter and a small divergence.
Posted Comments:
Y BoH
 (posted 2020-12-11 21:40:55.72)
When you are facing many boxes full of random mounted molded aspheric in the lab, trying to find one for a fiber coupler, it would be super useful if the laser marking on the side of the lens is not just meaning less model number but also the focal length of the lens.
YLohia
 (posted 2020-12-24 11:16:13.0)
Hello, thank you for your feedback. We are always looking to improve are existing products and will consider adding more useful engravings in the future.
user
 (posted 2020-09-08 20:35:54.0)
There is a typo on note 8 of the "Auto CAD PDF" for C340TMD-A. The working distance reference points are not given. "from" is typed twice
YLohia
 (posted 2020-09-09 10:46:54.0)
Hello, thank you for your feedback. We will correct this typo.
Ibrahim Kucukkara
 (posted 2020-08-25 04:03:45.893)
I have a 9mm TO can type L450G1 450nm laser diode with beam diameter of 6mm. Will you please suggest me a collimating lens and a proper adaptor and lens tube for a good collimation?
Thank you very much for your valuable help in advance.
Regards
İbrahim
YLohia
 (posted 2020-08-25 04:12:05.0)
Hello Ibrahim, thank you for contacting Thorlabs. Please see the Collimation Tutorial tab on this page for information on picking appropriate collimation lenses. I have reached out to you directly to discuss your application and requirements further.
Dear Ladies and Gentleman,
do you have a damage threshold for your N414-A
(CW operation),
thanks and Best Regards,
Gerald
nbayconich
 (posted 2020-03-20 02:10:21.0)
Thank you for contacting Thorlabs. At the moment we have not tested these optics for pulsed or CW damage threshold limitations. I will reach out to you directly to discuss your application.
user
 (posted 2019-04-01 14:34:42.947)
The aspheric coefficients in Zemax file have the same sign:
-0.00015041
-2.451e-006
-0.00000002547
The aspheric coefficients shown in this page have different signs:
-0.00015041
-2.451e-006
-0.00000002547
YLohia
 (posted 2019-04-04 09:02:11.0)
Hello, thank you for contacting Thorlabs. The aspheric coefficients change sign based on the direction the lens is pointing. The coefficients are correct in Zemax as well as the info icon. All of these coefficients should have the same sign. That being said, we did find an issue with the signs on the product page of this lens (https://www.thorlabs.com/thorproduct.cfm?partnumber=A397-A) and are working to correct it.
yusefzadib
 (posted 2017-04-14 15:36:40.633)
Hi
I used bellow products to setup a laser source:
1.C110TMD-A, f = 6.24 mm, NA = 0.40,
2.L638P700M, 638 nm, 700 mW, Ø5.6 mm,G Pin code
3.LDH56-P2/M, 30 mm Cage Plate Collimation Mount
4.SR9HF, ESD Protection and Strain Relief Cable, Pin Codes F and G, 7.5 V
However, I couldn't get a suitable collimated beam. It was
It should be mentioned that all focal distances were checked with precise devices.
tfrisch
 (posted 2017-04-28 09:46:34.0)
Hello, thank you for contacting Thorlabs. I notice that your source is a multimode laser diode which is expected to have greater divergence at collimation than a similar single mode source. I will reach out to you directly about your application.
richard
 (posted 2017-02-16 13:08:52.723)
Hello,
I was wondering if you could provide the concentricity tolerance between the mounted optic and the 9.24 mm OD of your M9 threaded mounted aspheres (such as A397TM-A).
tfrisch
 (posted 2017-03-01 05:00:18.0)
Hello, thank you for contacting Thorlabs. Most units will be seated better than the absolute tolerances of the lens and bore diameters, but 0.19mm is the worst case scenario.
chiwon.lee
 (posted 2017-01-09 10:06:57.053)
Hello, is it possible to manufature aspheric lenes with deep UV (250 nm) anti-reflective coating?
tfrisch
 (posted 2017-01-09 11:59:30.0)
Hello, thank you for contacting Thorlabs. So far into the UV, absorption will be come a concern. I will reach out to you directly with information on materials that may be suitable for a UV range asphere.
mbennahmias
 (posted 2016-06-27 10:54:25.437)
Hello,
I would like to know what is the laser induced damage threshold for this optical element / AR coating.
I am using a 0.2 W 375 nm laser diode and the diverging beam size at this location is ~ 0.1 to 0.2 mm
andrew.logan
 (posted 2014-12-16 13:52:10.44)
In the drawings for the 354560-A you give the tolerance on the lens diameter at +/- 0.15 mm, whereas Lightpath's 2014 pdf catalogue shows their typical tolerance as +/- 0.015 mm. Is this a typo, or does the 354560 have a tolerance that is an order of magnitude worse than what is typical of Lightpath?
Thanks
myanakas
 (posted 2015-01-14 02:19:40.0)
Response from Mike at Thorlabs: Thank you for your feedback. This is a typo, the correct tolerance is +/- 0.015. We are currently working to have the website updated to correct this.
moritz.kick
 (posted 2014-01-07 15:25:08.0)
Hi,
we want to couple a laser beam into and out of a fiber. The wavelength is 580 nm, we use the 460-HP fiber (MFD 3.5µm) and the Collimated Beam Diameter prior to Lens is about 1.3 mm.
I calculated f as 6.16 so the best aspheric lens for coupling the light into the fiber would be the item 352170-A. Is this correct so far?
But what kind of lense do I need to collimate the beam past the fiber. Can I use the same lense for both sides?
Thanks for your support
jlow
 (posted 2014-01-08 05:10:48.0)
Response from Jeremy at Thorlabs: At 580nm, the estimated MFD of the 460HP fiber is around 3.9µm nominally. Therefore, the ideal focal length lens would have around 6.8mm focal length. Using that number, the closest focal length asphere that would give you the best theoretical coupling efficiency would be the A375-A (7.5mm focal length). However, the difference with using the 6.24mm focal length asphere is relatively small (<0.5% absolute). For the collimation on the other end, it depends on the beam diameter and beam divergence you are looking to have on the output. Longer focal length would give you larger beam diameter and smaller beam divergence. You can use the same focal length lens on the output as well.
tcohen
 (posted 2012-09-04 10:05:00.0)
Response from Tim at Thorlabs: Thank you for contacting us. For the most efficiency in our support, a member of our China support team will contact you directly.
Response from Buki at Thorlabs.com
Thank you for participating in our Feedback Forum. We can provide custom coatings on our lenses. We have contacted you to get more information from you in order to provide a quote.
c2hollow
 (posted 2011-11-14 15:14:57.0)
Is it possible to get the C330TME-A with 405nm V-coating?
AR Coating Abbreviations
Abbreviation
Description
U
Uncoated: Optics Do Not have an AR Coating
A
Broadband AR Coating for the 350 - 700 nm or 400 - 600 nm Range
B
Broadband AR Coating for the 600 - 1050 nm or 650 - 1050 nm Range
C
Broadband AR Coating for the 1050 - 1620 nm or 1050 - 1700 nm Range
V
Narrowband AR Coating Designed for the Wavelength Listed in the Table Below
The table below contains all molded visible and near-IR aspheric lenses offered by Thorlabs. For our selection of IR molded aspheres, click here. The Item # listed is that of the unmounted, uncoated lens. An "X" in any of the five AR Coating Columns indicates the lens is available with that coating (note that the V coating availability is indicated with the design wavelength). The table to the right defines each letter and lists the specified AR coating range. Clicking on the X takes you to the landing page where that lens (mounted or unmounted) can be purchased.
OD = Outer Diameter M = Magnification LWT = Laser Window Thickness
WD = Working Distance DW = Design Wavelength TC = Center Thickness
EFL = Effective Focal Length NA = Numerical Aperture CA = Clear Aperture
EFL is specified at the design wavelength for the unmounted lens.
WD is specified at the design wavelength.
The AR coating is designed for 350 - 700 nm, but the substrate material has poor transmittance in the UV (click on the Info Icon for details).
Lenses with an LWT specification are designed for laser diode collimation; in these cases, the NA, WD, and wavefront are defined based on the presence of a laser window (not included) of the indicated thickness.
OD = Outer Diameter M = Magnification LWT = Laser Window Thickness
WD = Working Distance DW = Design Wavelength TC = Center Thickness
EFL = Effective Focal Length NA = Numerical Aperture CA = Clear Aperture
EFL is specified at the design wavelength for the unmounted lens.
WD is specified at the design wavelength.
Lenses with an LWT specification are designed for laser diode collimation; in these cases, the NA, WD, and wavefront are defined based on the presence of a laser window (not included) of the indicated thickness.
This working distance is measured from the lens to the window of the laser diode being collimated (not the emission point).
The AR coating is designed for 350 - 700 nm, but the substrate material has poor transmittance in the UV (click on the Info Icon for details).
OD = Outer Diameter M = Magnification LWT = Laser Window Thickness
WD = Working Distance DW = Design Wavelength TC = Center Thickness
EFL = Effective Focal Length NA = Numerical Aperture CA = Clear Aperture
EFL is specified at the design wavelength for the unmounted lens.
WD is specified at the design wavelength.
The AR coating is designed for 350 - 700 nm, but the substrate material has poor transmittance in the UV (click on the Info Icon for details).
Lenses with an LWT specification are designed for laser diode collimation; in these cases, the NA, WD, and wavefront are defined based on the presence of a laser window (not included) of the indicated thickness.
OD = Outer Diameter M = Magnification LWT = Laser Window Thickness
WD = Working Distance DW = Design Wavelength TC = Center Thickness
EFL = Effective Focal Length NA = Numerical Aperture CA = Clear Aperture
EFL is specified at the design wavelength for the unmounted lens.
WD is specified at the design wavelength.
The AR coating is designed for 350 - 700 nm, but the substrate material has poor transmittance in the UV (click on the Info Icon for details).
Lenses with an LWT specification are designed for laser diode collimation; in these cases, the NA, WD, and wavefront are defined based on the presence of a laser window (not included) of the indicated thickness.
This working distance is measured from the lens to the window of the laser diode being collimated (not the emission point).
OD = Outer Diameter M = Magnification LWT = Laser Window Thickness
WD = Working Distance DW = Design Wavelength TC = Center Thickness
EFL = Effective Focal Length NA = Numerical Aperture CA = Clear Aperture
EFL is specified at the design wavelength for the unmounted lens.
WD is specified at the design wavelength.
The AR coating is designed for 350 - 700 nm, but the substrate material has poor transmittance in the UV (click on the Info Icon for details).
Lenses with an LWT specification are designed for laser diode collimation; in these cases, the NA, WD, and wavefront are defined based on the presence of a laser window (not included) of the indicated thickness.
This working distance is measured from the lens to the window of the laser diode being collimated (not the emission point).
OD = Outer Diameter M = Magnification LWT = Laser Window Thickness
WD = Working Distance DW = Design Wavelength TC = Center Thickness
EFL = Effective Focal Length NA = Numerical Aperture CA = Clear Aperture
EFL is specified at the design wavelength for the unmounted lens.
WD is specified at the design wavelength.
The AR coating is designed for 350 - 700 nm, but the substrate material has poor transmittance in the UV (click on the Info Icon for details).
Lenses with an LWT specification are designed for laser diode collimation; in these cases, the NA, WD, and wavefront are defined based on the presence of a laser window (not included) of the indicated thickness.
This working distance is measured from the lens to the window of the laser diode being collimated (not the emission point).
OD = Outer Diameter M = Magnification LWT = Laser Window Thickness
WD = Working Distance DW = Design Wavelength TC = Center Thickness
EFL = Effective Focal Length NA = Numerical Aperture CA = Clear Aperture
EFL is specified at the design wavelength for the unmounted lens.
WD is specified at the design wavelength.
The AR coating is designed for 350 - 700 nm, but the substrate material has poor transmittance in the UV (click on the Info Icon for details).
Lenses with an LWT specification are designed for laser diode collimation; in these cases, the NA, WD, and wavefront are defined based on the presence of a laser window (not included) of the indicated thickness.
OD = Outer Diameter M = Magnification LWT = Laser Window Thickness
WD = Working Distance DW = Design Wavelength TC = Center Thickness
EFL = Effective Focal Length NA = Numerical Aperture CA = Clear Aperture
EFL is specified at the design wavelength for the unmounted lens.
WD is specified at the design wavelength.
The AR coating is designed for 350 - 700 nm, but the substrate material has poor transmittance in the UV (click on the Info Icon for details).
Lenses with an LWT specification are designed for laser diode collimation; in these cases, the NA, WD, and wavefront are defined based on the presence of a laser window (not included) of the indicated thickness.
OD = Outer Diameter M = Magnification LWT = Laser Window Thickness
WD = Working Distance DW = Design Wavelength TC = Center Thickness
EFL = Effective Focal Length NA = Numerical Aperture CA = Clear Aperture
EFL is specified at the design wavelength for the unmounted lens.
WD is specified at the design wavelength.
The AR coating is designed for 350 - 700 nm, but the substrate material has poor transmittance in the UV (click on the Info Icon for details).
Lenses with an LWT specification are designed for laser diode collimation; in these cases, the NA, WD, and wavefront are defined based on the presence of a laser window (not included) of the indicated thickness.
This working distance is measured from the lens to the window of the laser diode being collimated (not the emission point).
OD = Outer Diameter M = Magnification LWT = Laser Window Thickness
WD = Working Distance DW = Design Wavelength TC = Center Thickness
EFL = Effective Focal Length NA = Numerical Aperture CA = Clear Aperture
EFL is specified at the design wavelength for the unmounted lens.
WD is specified at the design wavelength.
The AR coating is designed for 350 - 700 nm, but the substrate material has poor transmittance in the UV (click on the Info Icon for details).
Lenses with an LWT specification are designed for laser diode collimation; in these cases, the NA, WD, and wavefront are defined based on the presence of a laser window (not included) of the indicated thickness.
This working distance is measured from the lens to the window of the laser diode being collimated (not the emission point).
OD = Outer Diameter M = Magnification LWT = Laser Window Thickness
WD = Working Distance DW = Design Wavelength TC = Center Thickness
EFL = Effective Focal Length NA = Numerical Aperture CA = Clear Aperture
EFL is specified at the design wavelength for the unmounted lens.
WD is specified at the design wavelength.
The AR coating is designed for 350 - 700 nm, but the substrate material has poor transmittance in the UV (click on the Info Icon for details).
Lenses with an LWT specification are designed for laser diode collimation; in these cases, the NA, WD, and wavefront are defined based on the presence of a laser window (not included) of the indicated thickness.
This working distance is measured from the lens to the window of the laser diode being collimated (not the emission point).
OD = Outer Diameter M = Magnification LWT = Laser Window Thickness
WD = Working Distance DW = Design Wavelength TC = Center Thickness
EFL = Effective Focal Length NA = Numerical Aperture CA = Clear Aperture
EFL is specified at the design wavelength for the unmounted lens.
WD is specified at the design wavelength.
The AR coating is designed for 350 - 700 nm, but the substrate material has poor transmittance in the UV (click on the Info Icon for details).
Lenses with an LWT specification are designed for laser diode collimation; in these cases, the NA, WD, and wavefront are defined based on the presence of a laser window (not included) of the indicated thickness.
This working distance is measured from the lens to the window of the laser diode being collimated (not the emission point).