Concave Mirrors: UV Broadband Dielectric Coating (350 - 400 nm)

  • Focal Lengths from 25 - 100 mm
  • 1" Diameter
  • Dielectric Coating for 350 - 400 nm
  • No Chromatic Aberration Introduced


f = 50 mm

Focus Polychromatic Beams without Chromatic Aberration


f = 100 mm

Related Items

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Common Specifications
Dielectric Coating Range 350 - 400 nm; Ravg >99%
Clear Aperture >90% of Diameter
Surface Irregularity λ/4 @ 633 nm
Surface Quality 20-10 Scratch-Dig
Diameter Tolerance +0.0/-0.2 mm
Thickness Tolerance ±0.2 mm
Substrate N-BK7a
Backside Surface Fine Ground and Engraved with Part Number
(Not Polished)
  • 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.


  • Dielectric Coating: 350 - 400 nm (-E01)
  • >99% Average Reflectivity in Dielectric Coating Range
  • 1" Diameter
  • Focal Lengths Range from 25 mm - 100 mm

Thorlabs' Broadband Dielectric Concave Mirrors are designed for light collection, imaging, and focusing applications. These reflective optics focus light without introducing chromatic aberration, making them especially suitable for broadband sources.

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

Thorlabs also offers metallic concave mirrors that operate over a broader wavelength range at the expense of lower reflectivity. Please contact Tech Support for custom versions of these optics.

Optical Coatings and Substrates
Optic Cleaning Tutorial

These plots show the reflectivity of our -E01 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 -E01 Coating, 6° and 45° AOI

Posted Comments:
tcohen  (posted 2012-04-05 15:30:00.0)
Update from Tim at Thorlabs: These have fine ground backs and as such will be unusable for your application. However, we are able to offer a custom with a polished backside. I have contacted you with more information.
tcohen  (posted 2012-04-05 15:06:00.0)
Response from Tim at Thorlabs: Thank you for your feedback. I am looking into the reflection/transmission of these mirrors when incident light is on the uncoated side and I will update you with the information soon!
junge  (posted 2012-04-05 06:19:36.0)
Hello, is the backsurface of the mirror transparent so that it can be used to set up a FPI? Thanks a lot, Christian

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" (25.4 mm) -E01 Broadband Dielectric Concave Mirrors (350 - 400 nm)

Item # Focal Length Center Thickness Edge Thickness Radius of Curvature Reference Drawing
CM254-025-E01 25 mm 6.0 mm 7.6 mm 50.0 mm (1.97") Concave Mirror Drawing
CM254-050-E01 50 mm 6.8 mm 100.0 mm (3.94")
CM254-075-E01 75 mm 6.5 mm 150.0 mm (5.91")
CM254-100-E01 100 mm 6.4 mm 200.0 mm (7.87")
Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
CM254-025-E01 Support Documentation
CM254-025-E01Ø1" Dielectric-Coated Concave Mirror, 350 - 400 nm, f = 25 mm
CM254-050-E01 Support Documentation
CM254-050-E01Ø1" Dielectric-Coated Concave Mirror, 350 - 400 nm, f = 50 mm
CM254-075-E01 Support Documentation
CM254-075-E01Ø1" Dielectric-Coated Concave Mirror, 350 - 400 nm, f = 75 mm
CM254-100-E01 Support Documentation
CM254-100-E01Ø1" Dielectric-Coated Concave Mirror, 350 - 400 nm, f = 100 mm