Concave Mirrors: Visible Dielectric Coating (400 - 750 nm), Back Side Polished


  • Focal Lengths from 12 - 100 mm
  • Ø1/2" or Ø1" Sizes
  • Dielectric Coating for 400 - 750 nm
  • Back Sides Polished to λ/4 Flatness

CM127P-012-E02

Ø1/2''

CM254P-025-E02

Ø1''

CM254P-100-E02

Ø1''

Related Items


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Common Specifications
Dielectric Coating Wavelength Range 400 - 750 nm
Dielectric Coating Reflectance
(0° to 45° AOI)
Rs, avg, and Rp, avg, > 99%
Available Diameters 1/2" and 1"
Clear Aperture >90% of Diameter
Diameter Tolerance +0.0 / -0.2 mm
Thickness Tolerance ±0.2 mm
Substrate N-BK7a
Front Surface Quality (Concave Side) 20-10 Scratch-Dig
Front Surface Accuracy (Concave Side) λ/4 at 633.0 nm
Back Surface (Plano Side) Polished
Back Surface Quality (Plano Side) 40-20 Scratch-Dig
Back Surface Flatness (Plano Side) λ/4 at 633.0 nm
  • Click Link for Detailed Specifications on the Substrate
Dielectric Concave Mirrors Selection Guide
UV 350 - 400 nm
Visible 400 - 750 nm 400 - 750 nm, Back Side Polished
NIR 750 - 1100 nm 750 - 1100 nm, Back Side Polished
Telecom 1280 - 1600 nm

See the Concave Mirror Guide tab, above, for our complete selection of concave mirrors.

Features

  • High-Reflectance Dielectric Coating for 400 - 750 nm (-E02)
  • >99% Average Reflectance Over Dielectric Coating Range
  • Two Diameter Options: 1/2" and 1"
  • Focal Lengths Range from 12 mm to 100 mm
  • Polished Back Surface
    • Surface Flatness: λ/4 at 633 nm
    • Surface Quality: 40-20 Scratch-Dig

Thorlabs' Broadband Dielectric Concave Mirrors are designed for a wide variety of light collection, imaging, and focusing applications. These reflective optics focus light without chromatic aberration, making them especially suitable for broadband sources. With a surface accuracy of λ/4 at 633 nm, these mirrors provide excellent image quality.

Since the back sides are also polished to a λ/4 flatness at 633 nm with a surface quality of 40-20 scratch-dig, these mirrors will transmit a very small portion (<<1%) of the incident light within the coating band, thereby enabling sampling of the incident light without the need for additional optical elements.

Although the transmission properties of back side polished mirrors are desirable in certain applications, there are tradeoffs to consider. By polishing the back side of a mirror, more light will be reflected by the back surface, thereby increasing the number of stray beams present in the lab. When using back side polished mirrors, ensure that all stray beams are blocked appropriately. Thorlabs offers an extensive line of laboratory safety equipment (e.g., blackout materials, beam dumps, goggles) to facilitate safety precautions. In addition to safety concerns when using back side polished mirrors, unwanted interference effects can arise between the light reflected from the front surface and that reflected from the optically flat back surface. Finally, broadband dielectric mirrors are fabricated using a complex multilayer dielectric coating technique, which affects the transmitted light. Both the wavefront and the polarization of the transmitted beam will be altered, and these effects are temperature dependent.

All of the mirrors on this page can be mounted by our Precision Kinematic Mirror Mounts.

Thorlabs also offers Plano Back Side Polished Mirrors.

Optical Coatings and Substrates
Optic Cleaning Tutorial

These plots show the reflectance of our -E02 dielectric coating for a typical coating run. The shaded region in each graph denotes the spectral range over which the coating is highly reflective. Due to variations in each run, this recommended spectral range is narrower than the actual range over which the optic will be highly reflective. If you have any concerns about the interpretation of this data, please contact Tech Support. For applications that require a mirror that bridges the spectral range between two dielectric coatings, please consider a metallic concave mirror.

Excel Spreadsheet with Raw Data for -E02 Coating, 8° and 45° AOI


Posted Comments:
Lauren Weiss  (posted 2022-02-14 13:52:52.4)
Hello, I purchased the CM127P-050_E02 to use in a cavity. It is more transmissive than the graphs on this site suggest. I found that for 852 nm light, when I send 49 mW in at 0 incidence, I get 2.85 mW out, a transmission rate of 5.81%.
jgreschler  (posted 2022-02-17 04:02:42.0)
Thank you for reaching out to Thorlabs. Due to variations in each run, this recommended spectral range is narrower than the actual range over which the optic will be highly reflective. For 852nm I would recommend using the NIR dielectric coated mirrors, suffix -E03.

Concave Mirrors Options
Mirror Type High-Reflectance Coating Wavelength
UV Enhanced Aluminum 250 - 450 nm
Aluminum 450 nm - 20 µm
Silver 450 nm - 20 µm
Gold 800 nm - 20 µm
E01 Dielectric 350 - 400 nm
E02 Dielectric 400 - 750 nm
E02 Dielectric, Back Side Polished
E03 Dielectric 750 - 1100 nm
E03 Dielectric, Back Side Polished
E04 Dielectric 1280 - 1600 nm
Crystalline 1064 nm, 1156 nm, 1397 nm, or 1550 nm

Concave Mirror Selection Guide

Thorlabs offers concave mirrors with both metallic and dielectric stack reflective coatings. Metallic-coated mirrors offer relatively high reflectance (90-95%) over a wide wavelength range, while dielectric-coated mirrors provide even higher reflectance (>99%) but over a smaller wavelength range. See the table to the right for an overview of the various coatings we offer for our concave mirrors. All coating options are available on optics with diameters ranging from Ø1/2" to Ø75 mm. Metallic mirrors are available with focal lengths from 9.5 - 1000 mm, while dielectric mirrors are available with focal lengths from 12 - 1000 mm.

Below are reflectance plots for our metallic-, dielectric-, and crystalline-coated concave mirrors. To view our selection of mirrors available with a particular coating, either click on the graphed line of interest or the corresponding coating name in the legend. Graphs for the matallic- and dielectrc-coated mirrors are shown for an angle of incidence (AOI) of 8 or 6 degrees. Graphs for the crystalline-coated mirrors are shown for an AOI of 0 degrees.

Metallic Concave Mirror 8 AOI Reflectivity
Click on a particular graphed line or the corresponding name in the legend to view concave mirrors with that coating option.
Metallic-Coated Concave Mirrors are available in UV Enhanced Aluminum, Aluminum, Silver, and Gold.

UV Aluminum (F01) Aluminum (G01) Silver (P01) Gold (M01) UV Aluminum (F01) Aluminum (G01) Silver (P01) Gold (M01)


Concave Dielectric Coated Mirrors

-E02 Coating Range, 8° AOI
Click to Enlarge
Raw Data
Reflectance of -E02 Dielectric-Coated Concave Mirrors at 8° AOI.
These mirrors are also available with a Back Side Polish.
-E04 Coating Range, 6° AOI
Click to Enlarge
Raw Data
Reflectance of -E03 Dielectric-Coated Concave Mirrors at 6° AOI.
These mirrors are also available with a Back Side Polish.

Concave Crystalline Coating Mirrors 

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Ø1/2" Broadband Dielectric Concave Mirrors (400 - 750 nm), Back Side Polished

Item # Focal Length Center Thickness Edge Thickness Radius of Curvature Reference Drawing
CM127P-012-E02 12.0 mm 3.0 mm 3.8 mm 24.0 mm (0.94") Concave Mirror Drawing
CM127P-025-E02 25.0 mm 3.4 mm 50.0 mm (1.97")
CM127P-050-E02 50.0 mm 3.2 mm 100.0 mm (3.94")
Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
CM127P-012-E02 Support Documentation
CM127P-012-E02Ø1/2" Dielectric-Coated Concave Mirror, 400 - 750 nm, f = 12 mm, Back Side Polished
$98.56
Today
CM127P-025-E02 Support Documentation
CM127P-025-E02Ø1/2" Dielectric-Coated Concave Mirror, 400 - 750 nm, f = 25 mm, Back Side Polished
$98.56
Today
CM127P-050-E02 Support Documentation
CM127P-050-E02Ø1/2" Dielectric-Coated Concave Mirror, 400 - 750 nm, f = 50 mm, Back Side Polished
$98.56
Today
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Ø1" Broadband Dielectric Concave Mirrors (400 - 750 nm), Back Side Polished

Item # Focal Length Center Thickness Edge Thickness Radius of Curvature Reference Drawing
CM254P-025-E02 25.0 mm 6.0 mm 7.6 mm 50.0 mm (1.97") Concave Mirror Drawing
CM254P-050-E02 50.0 mm 6.8 mm 100.0 mm (3.94")
CM254P-075-E02 75.0 mm 6.5 mm 150.0 mm (5.91'')
CM254P-100-E02 100.0 mm 6.4 mm 200.0 mm (7.97'')
Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
CM254P-025-E02 Support Documentation
CM254P-025-E02Ø1" Dielectric-Coated Concave Mirror, 400 - 750 nm, f = 25 mm, Back Side Polished
$126.49
Today
CM254P-050-E02 Support Documentation
CM254P-050-E02Ø1" Dielectric-Coated Concave Mirror, 400 - 750 nm, f = 50 mm, Back Side Polished
$126.49
Today
CM254P-075-E02 Support Documentation
CM254P-075-E02Ø1" Dielectric-Coated Concave Mirror, 400 - 750 nm, f = 75 mm, Back Side Polished
$126.49
Today
CM254P-100-E02 Support Documentation
CM254P-100-E02Ø1" Dielectric-Coated Concave Mirror, 400 - 750 nm, f = 100 mm, Back Side Polished
$126.49
Today