Unmounted, AR-Coated Bandpass Colored Glass Filters


  • AR Coating for 245 - 400 nm or 350 - 700 nm
  • Ø25 mm Filters
  • Broadband Alternative to Dielectric Bandpass Filters

FGUV11-UV

FGS900-A

Application Idea

FGB37-A Mounted in KB1P
Quick-Release Mount

Related Items


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UV AR Coating
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The blue shaded region indicates the specified 245 - 400 nm wavelength range for optimum performance.
A AR Coating
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The blue shaded region indicates the specified 350 - 700 nm wavelength range for optimum performance.

Features

  • Transmissive at UV or Visible Wavelengths
  • AR Coated for 245 - 400 nm or 350 - 700 nm
  • Ø25 mm Filter
  • Peak Transmission Greater than 90% in Specified Range
  • Easily Mounted in SM1-Compatible Mounts

Thorlabs is pleased to offer a selection of its bandpass colored glass filters with a broadband antireflective coating designed for either the 245 - 400 nm (-UV) or 350 - 700 nm (-A) wavelength range. The broadband AR coating is deposited on both faces of a Schott® glass substrate that has been selected for its high transmission in the ultraviolet or visible. These Ø25 mm filters can be easily mounted in our manual or motorized filter wheels. They can also be mounted in our series of SM1 (1.035"-40) lens tubes.

The high-performance, multilayer, broadband -UV or -A coating deposited on each filter is designed to minimize surface reflections within the specified range, thereby increasing the amount of light transmitted within the specified wavelength region. This helps to improve measurement sensitivity under low light conditions. These coatings provide an average reflectivity that is less than 0.5% over the specified range when light is normally incident on the filter surface. Please see below for a representative transmission curve for each filter type, or refer to the Comparison tab for plots of the performance of the coated and uncoated filters.

For applications in the ultraviolet, the FGUV5-UV and FGUV11-UV are recommended for use in the 240 - 395 nm and 275 - 375 nm spectral ranges, respectively. The FGUV5-UV provides greater than 98% peak transmission within the specified range, while the FGUV11-UV features greater than 90% peak transmission and a nearly zero transmission up into the infrared. For applications at visible wavelengths, consider the FGS900-A and FGB37-A, designed for use in the 315 - 710 nm and 335 - 610 nm spectral ranges, respectively. The FGS900-A provides greater than 90% peak transmission over the visible wavelength range and suppresses wavelengths up into the infrared, while the FGB37-A provides greater than 98% peak transmission in the visible.

Several of the colored glasses used for our filters are fluorescent at certain wavelengths; for more details on how this may affect certain applications, contact Technical Support. For narrowband sources, we recommend our dielectric bandpass filters.

If an appropriate filter is not listed here, Thorlabs also provides an extended variety of uncoated bandpass colored glass filters for wavelengths extending from the ultraviolet to the infrared.

Colored Glass Selection Guide
Bandpass Longpass Color Temperature Balancing
Mounted Unmounted AR Coated Mounted Unmounted Unmounted
Item # FGUV5-UV FGUV11-UV FGS900-A FGB37-A
Schott® Glass # UG5 UG11 KG3 BG40
AR Coating Range 245 - 400 nm 245 - 400 nm 350 - 700 nm 350 - 700 nm
Recommended Range* 240 - 395 nm 275 - 375 nm 315 - 710 nm 335 - 610 nm

*The recommended range is the range for which the wavelength-dependent transmission is >50% of the peak transmission.

General Specifications
Diameter 25 mm
Thickness 2 mm
Clear Aperture 80% of Diameter
Ravg <0.5% in Coating Range
Surface Quality 40-20 Scratch-Dig
Surface Flatness <λ @ 632.8 nm
Dimensional Tolerance +0.0/-0.4 mm
Wedge <3 arcmin
Colored Filter Dimensions
Item # Recommended Range
FGUV5-UV 240 - 395 nm
FGUV11-UV 275 - 375 nm
FGS900-A 315 - 710 nm
FGB37-A 335 - 610 nm

Effect of AR Coating on Transmission Properties

The bandpass colored glass filters shown on this page have been AR coated for either the 245 - 400 nm range (-UV) or the 350 - 700 nm range (-A). These filters are also available without AR coatings, but their transmission in the specified range is significantly diminished, as shown in the graphs below. At the peak transmission wavelength, the AR coatings provide an 8 - 10% increase in the total transmission.

The shaded region in each graph denotes the range over which the wavelength-dependent transmission is >50% of the peak transmission. This range is also listed in the table above.


Posted Comments:
Brenda Chng  (posted 2023-12-05 14:02:24.463)
FGB37-A - Ø25 mm BG40 Colored Glass Filter, AR Coated: 350 - 700 nm Hi, Is it possible to quote for FGB37 in a 5x5mm square piece? Qty: 1,2,10,50,100 pc
cdolbashian  (posted 2023-12-11 09:41:54.0)
Thank you for reaching out to us with this inquiry. This is likely something we can do for you! Unfortunately, via this feedback form, we cannot quote you for items (custom or otherwise) nor can we evaluate the price and leadtime for such a custom though I have put you in touch with the correct team. For future customer requests, in terms of evaluating viability, please contact techsupport@thorlabs.com.
Paul Dumont  (posted 2022-12-20 14:59:18.41)
Dear all, From my experience, in the long term, UG11 polished surfaces are altered when in contact with the ambiant humidity. Can the coating prevent that effect ? Best regards,
cdolbashian  (posted 2022-12-28 10:12:32.0)
Thank you for reaching out to us Paul! While we have not tested these for long term-high humidity performance, I can say that these are non-porous coatings, and we would expect them to perform better than bare, uncoated, UG11.
aklossek  (posted 2014-07-01 08:55:03.06)
Dear ladies and gentlemen, I am very interested in your filter FGB37-A. Unfortunately I need a slightly different size: 30 mm diameter and about 1,8 mm thickness. Is it possible to get this size. Or maybe you have a mount to compensate the diameter. Best regards André Klossek
jlow  (posted 2014-07-14 10:24:34.0)
Response from Jeremy at Thorlabs: We can do this as a custom. We will contact you directly for a quote.
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Unmounted Bandpass Colored Glass Filters, AR Coated: 245 - 400 nm

Item # Diameter Thickness Clear Aperture Schott® Glass # AR Coating Recommended Range*
FGUV5-UV 25 mm 2 mm 80% of Diameter UG5 245 - 400 nm 240 - 395 nm
FGUV11-UV 25 mm 2 mm 80% of Diameter UG11 245 - 400 nm 275 - 375 nm

*The recommended range is the range for which the wavelength-dependent transmission is >50% of the peak transmission. This region is shaded in the graphs shown above.

Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
FGUV5-UV Support Documentation
FGUV5-UVCustomer Inspired! Ø25 mm UG5 Colored Glass Filter, AR Coated: 245 - 400 nm
$117.81
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FGUV11-UV Support Documentation
FGUV11-UVCustomer Inspired! Ø25 mm UG11 Colored Glass Filter, AR Coated: 245 - 400 nm
$117.81
Today
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Unmounted Bandpass Colored Glass Filters, AR Coated: 350 - 700 nm

Item # Diameter Thickness Clear Aperture Schott® Glass # AR Coating Recommended Rangea
FGS900-A 25 mm 2 mm 80% of Diameter KG3 350 - 700 nm 315 - 710 nm
FGB37-A 25 mm 2 mm 80% of Diameter BG40 350 - 700 nm 335 - 610 nmb

a The recommended range is the range for which the wavelength-dependent transmission is >50% of the peak transmission. This region is shaded in the graphs shown above.
b The transmission of the FGB37-A is between 0% and 50% in the 610 - 700 nm spectral range.

Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
FGS900-A Support Documentation
FGS900-ACustomer Inspired! Ø25 mm KG3 Colored Glass Filter, AR Coated: 350 - 700 nm
$71.76
Today
FGB37-A Support Documentation
FGB37-ACustomer Inspired! Ø25 mm BG40 Colored Glass Filter, AR Coated: 350 - 700 nm
$88.89
Today