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Fresnel Lenses


  • Reduced Thickness and Weight Compared to Standard Lenses
  • Ideal for Illumination and Light Collection Applications
  • Four Focal Lengths Available

FRP0510

Ø1/2"

FRP125

Ø1"

FRP232

Ø2"

Fresnel Lenses (Right) Consist of Sections with
Similar Curvature to Standard Lenses (Left)

Related Items


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Transmission Graph of Fresnel Lens
Click to Enlarge

Excel Spreadsheet with Raw Data
The shaded region in this plot denotes the spectral range over which we recommend using these lenses. All our Fresnel lenses have a nominal thickness of 1.5 mm, and only minor differences are observed for different focal lengths.
Fresnel Lens in Cage System
Click to Enlarge

Ø2" Fresnel Lens in 60 mm Cage System with LCPA1 Alignment Plate to Check Beam Diameter and Centration
Limited Zemax Files
Click on the Limited Zemax Files Tab above to access the limited Zemax file download. Our entire Zemax Catalog is also available.

Features

  • Focal Length of 10 mm, 25 mm, 32 mm, or 51 mm
  • Optical-Grade Acrylic is Transmissive from 400 - 1100 nm (See Graph at Right)
  • Compact, 1.5 mm Thick Substrate Minimizes Absorption
  • Used in Light Gathering, Illumination, and Homogenization Applications

Thorlabs' Fresnel Lenses offer light focusing and collimation without the bulk associated with traditional lenses. Our Fresnel lenses are effectively 1.5 mm thick across their entire diameter, and this uniform thickness, combined with the optical-grade acrylic substrate, reduces their weight by over 90% versus glass lenses of comparable focal length and diameter.a These properties make them ideal for building compact optical systems.

Our lenses are offered in 1/2", 1", and 2" diameters, and they provide high transmission in the 400 - 1100 nm spectral range (see graph at right). As shown in the schematic at the top of the page, they consist of a grooved side and a plano side. In order to minimize the substrate thickness, stepwise discontinuities are introduced at regular radial spacings, creating grooves. Hence, Fresnel lenses can be thought of as a series of concentric rings.

Fresnel lenses are often used to homogenize the output of LEDs, focus light onto a point detector, or concentrate sunlight into solar cells. For the lenses sold on this page, each step has a 10° pitch (illustrated by the diagram in the Specs tab). This pitch angle causes distortions that make the lenses unsuitable for imaging applications.

Optic Cleaning Tutorial

To mount our Fresnel lenses, we recommend using our LMR05(/M), LMR1(/M), or LMR2(/M) Fixed Lens Mounts, which use a retaining ring to secure the optic. Do not overtighten the retaining ring since this may cause the grooves to wear. Our rubber Stress-Free Retaining Rings can be used in place of the standard aluminum rings to reduce the stress on the optic surface. The grooved side of the lens should be oriented to face the collimated beam, and the plano side should face the divergent source. The JEL10 Eye Loupe can help determine which side of the lens is grooved. Since the lenses are only 1.5 mm thick, they are too thin for mounts that hold optics with setscrews.

Thorlabs also offers aspheric condensers with diffusive surfaces that provide uniform illumination in the far field, as well as a complete selection of lenses.

a. Weight reduction calculated by comparison to our Aspheric Condensers with Diffusers.

Item #FRP0510FRP125FRP232FRP251
Focal Length 10 mm 25 mm 32 mm 51 mm
Focal Length Tolerance ±5%
Diameter 1/2" (12.7 mm) 1" (25.4 mm) 2" (50.8 mm) 2" (50.8 mm)
Diameter Tolerance ±0.125 mm
Thickness 1.5 mm (Nominal)a
Thickness Tolerance ±0.25 mm
Clear Aperture >90% of Diameter
Groove Spacingb,c 0.10 mm 0.25 mm 0.2 mm 0.33 mm
Pitchb 10°
Design Wavelength 588 nm
Refractive Index 1.49
Abbe Number (VD) 55.3
Parallelism <3 arcmin
Surface Quality 80-50 Scratch-Dig
Substrate Material Optical-Grade Acrylic
  • The thickness varies with radius because of the grooved side of the substrate.
  • Defined in the schematic below.
  • Although these lenses are not recommended for imaging applications, smaller groove spacings will improve image quality.

 

Schematic of Fresnel Lens Surfaces
Click to Enlarge

This schematic defines the groove spacing and pitch angle in our Fresnel lenses. Note that the lengths are not to scale.
Transmission Graph of Fresnel Lens
Click to Enlarge

Excel Spreadsheet with Raw Data
The shaded region in this plot denotes the spectral range over which we recommend using these lenses. All our Fresnel lenses have a nominal thickness of 1.5 mm, and only minor differences are observed for different focal lengths.

The linked Zemax files are a theoretical approximation of the performance of each lens. In place of a grooved structure, each file models a sloped surface with infinitesimal thickness at each radial position. This creates limitations, including the inability to view scattering information due to the pitch and groove spacing of the lens. In addition, the optical coefficients in each file are not from the data used at manufacturing; the coefficients are calculated using the necessary optical prescription to focus collimated light at the proper axial distance from the back surface of the lens. These limitations reduce the realistic modeling of the Fresnel lenses sold below.


Posted Comments:
alst  (posted 2018-08-16 09:03:29.103)
Hi, The zemax files don't seem to work, there is an error saying 'invalid edge thickness on surface 1'. What's the reason for this? Regards, Alfred
YLohia  (posted 2018-08-29 02:23:43.0)
Hello Alfred, thank you for contacting Thorlabs. We have tried all of the Zemax files on this page and found all of them to be working perfectly fine. What product are you referring to specifically? Could you please send a screenshot of the issue to techsupport@thorlabs.com? What version of Zemax are you using and with what operating system? Is there another machine you can try this on? I have reached out to you directly to troubleshoot further.
anne.cournol  (posted 2016-12-08 09:14:26.8)
Is the Fresnel Lenses material compatible with ultra vacuum ?
tfrisch  (posted 2016-12-14 01:14:53.0)
Hello, thank you for contacting Thorlabs. Unfortunately, acrylic is not a material suitable for vacuum use. I apologize for the inconvenience.
user  (posted 2014-09-10 00:26:49.39)
What is the maximum operating temperature of your fresnel lenses?
besembeson  (posted 2014-09-12 03:41:25.0)
Response from Bweh: The maximum operating temperature of our Fresnel lenses is 80°C.
ralph  (posted 2014-06-10 12:08:01.367)
Do you have the lens design parameters for FRP232? Specifically spherical base curvature, depth of annular zones. A Zemax or similar file would be great.
myanakas  (posted 2014-07-03 05:17:19.0)
Response from Mike at Thorlabs: Thank you for your feedback. Limited .ZAR and .ZMX Zemax files have now been added to the web in the "Limited Zemax Files" tab and in the supporting documents found by clicking the red "Docs" icon. The linked Zemax files are a theoretical approximation of the performance of each lens. We could not show the full structure as this information is proprietary to the manufacturer if the Fresnel lenses. We apologize for any inconvenience this may have caused.
Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
FRP0510 Support Documentation
FRP0510Ø1/2" Fresnel Lens, f = 10 mm
$18.28
Today
FRP125 Support Documentation
FRP125Ø1" Fresnel Lens, f = 25 mm
$22.59
Today
FRP232 Support Documentation
FRP232Ø2" Fresnel Lens, f = 32 mm
$32.31
Today
FRP251 Support Documentation
FRP251Ø2" Fresnel Lens, f = 51 mm
$23.64
Today
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Last Edited: Sep 17, 2013 Author: Dan Daranciang