AR-Coated, N-BK7 Ground Glass Diffusers

  • AR-Coated for 350 - 700 nm or 650 - 1050 nm
  • Unmounted Diffusers Offered in 120, 220, 600, and 1500 Grit Polishes
  • Polished for Greater Uniformity than Sand Blasting



AR-Coated Transfusers Provide Enhanced Transmission Compared to Their Uncoated Counterparts

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Diffuser Selection Guide
Ground Glass Diffusers
Standard Diffusers N-BK7 Substrate Unmounted, Uncoated 350 nm to 2.0 µm
Unmounted, AR-Coated 350 nm - 700 nm
650 nm - 1050 nm
Mounted, Uncoated 350 nm - 2.0 µm
UVFS Substrate Unmounted, Uncoated 185 nm - 2.0 µm
Diffuse Reflectors N-BK7 Substrate Unmounted, UV-Enhanced Aluminum Coated 250 nm - 450 nm
Unmounted, Protected Silver Coated 450 nm - 20 µm
Unmounted, Protected Gold Coated 800 nm - 20 µm
Alignment Disks
Engineered Diffusers
Diffuser Kits


  • Ø1", Unmounted Circular Diffusers
  • One of Two AR Coatings on Both Surfaces:
    • 350 - 700 nm (A Coating)
    • 650 - 1050 nm (B Coating)
  • Substrate Material: N-BK7

Thorlabs' AR-Coated N-BK7 Ground Glass Diffusers can be used in a variety of applications requiring a diffuse Gaussian-like distribution. They are offered in 120, 220, 600, and 1500 grit polishes with an AR coating deposited on both sides for either 350 - 700 nm or 650 - 1050 nm. These diffusers offer improved transmission over their uncoated counterparts (see the Graphs Tab for more details).

Polished diffusers are advantageous over sand blasted diffusers, as their surface have greater uniformity. The various grits provide a range from fine to coarse scattering. A finer grit (e.g. 1500) has a small diffusion pattern, while a coarser grit (e.g. 120) will have a larger diffuser pattern. When mounting the diffusers, the grit polished side should face away from the source.

For applications requiring specific divergence angles, spatial distribution of the illumination, and intensity profiles, our engineered diffusers are more suitable. Thorlabs also offers UV Fused Silica Diffusers for applications that extend into the ultraviolet portion of the spectrum.

Common Specifications
Diameter 1.00" (25.4 mm)
Thickness 2.0 mm
Clear Aperture >90% of Diameter
Surface Flatness of Smooth Side (@ 633 nm) <4λ
Surface Quality of Smooth Side 80-50 Scratch-Dig
Parallelism <3 arcmin
Item # Grit AR Coating Range
DG10-120-A 120 350 - 700 nm
Ravg<0.5%, 0° AOI (Polished Side)a
DG10-220-A 220
DG10-600-A 600
DG10-1500-A 1500
DG10-120-B 120 650 - 1050 nm
Ravg<0.5%, 0° AOI (Polished Side)a
DG10-220-B 220
DG10-600-B 600
DG10-1500-B 1500
  • The ground side is coated but does not meet this reflectivity specification.

The coated diffusers offer increased transmission over their uncoated counterparts, which are represented by the blue curves in the graphs below. The blue-shaded region represents the wavelength range over which the AR coating is specified. The -A coating is specified for 350 - 700 nm and the -B coating for 650 - 1050 nm. Please note that the transmission values are affected by the manner in which the data is collected. An integrating sphere is used along with a spectrometer, and as the grit values get smaller the light is more dispersed, making it difficult to collect all of the light into the spectrometer. Therefore, lower grit values will appear to have a lower transmission.

Bidirectional Scattering Distribution Function Graphs

These graphs describe the diffusers' behavior before the AR coating has been applied. This data was taken by directing a HeNe laser at a diffuser and collecting the light with a receiver that was rotated around the diffuser to measure the angle-resolved scatter (ARS). The bidirectional scattering distribution function (BSDF), which is found by dividing the ARS by the cosine of the angle between the input beam and the receiver, measures the amount of scattering that occurs after light permeates the diffuser. The X axis of these graphs is the angle at which the scatter is occurring. This is why at 0° there can be a spike; this spike is representative of the specular beam going through the diffuser.  

Posted Comments:
Hideyuki Omura  (posted 2021-11-10 20:57:29.337)
Which country's standard does the "Grit" conform to, ANSI (American National Standards Institute) or Federation of European Producers of Abrasives (FEPA)? I would like to know grit number of DG 10 series in JIS (Japanese Industrial Standard). Could you provide the information?
jgreschler  (posted 2021-11-12 04:04:30.0)
Thank you for reaching out to Thorlabs. The grit size referenced in our ground glass diffusers refers to the abrasive particle size used in fabrication. 120 grit corresponds to ~142um, 220 is ~66um, 600 is ~15um, and 1500 is ~5um. All particle sizes are average. Please note that the size of the abrasive particles is not necessarily the size of the features on the glass surface, however we don't actively characterize the latter parameter. We are unable to provide the requested characterization in the JIS standard as a result of this.
wychang  (posted 2018-09-10 22:51:36.2)
Do you have the BSDF(Bidirectional scattering distribution function) data of DG10-120-B? It's better to have LightTools format. Thank you.
nbayconich  (posted 2018-10-04 01:02:22.0)
Thank you for contacting Thorlabs. We do not carry any BSDF data files for Zemax or Lighttools for our ground glass diffusers to simulate scattering at the moment.
siseveri  (posted 2017-02-28 10:51:44.847)
Do you have any data consering the scattering angle on the grit polished side for the wavelength 532nm? Thank you!
tfrisch  (posted 2017-03-13 01:45:44.0)
Hello, thank you for contacting Thorlabs. I will reach out to you directly about scattering angle.

N-BK7 Ground Glass Diffusers (AR Coating: 350 - 700 nm)

Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
DG10-120-A Support Documentation
DG10-120-AØ1" N-BK7 Ground Glass Diffuser, 120 Grit, ARC: 350-700 nm
DG10-220-A Support Documentation
DG10-220-AØ1" N-BK7 Ground Glass Diffuser, 220 Grit, ARC: 350-700 nm
DG10-600-A Support Documentation
DG10-600-A Ø1" N-BK7 Ground Glass Diffuser, 600 Grit, ARC: 350-700 nm
DG10-1500-A Support Documentation
DG10-1500-AØ1" N-BK7 Ground Glass Diffuser, 1500 Grit, ARC: 350-700 nm

N-BK7 Ground Glass Diffusers (AR Coating: 650 - 1050 nm)

Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
DG10-120-B Support Documentation
DG10-120-BØ1" N-BK7 Ground Glass Diffuser, 120 Grit, ARC: 650-1050 nm
DG10-220-B Support Documentation
DG10-220-BØ1" N-BK7 Ground Glass Diffuser, 220 Grit, ARC: 650-1050 nm
DG10-600-B Support Documentation
DG10-600-BØ1" N-BK7 Ground Glass Diffuser, 600 Grit, ARC: 650-1050 nm
DG10-1500-B Support Documentation
DG10-1500-BØ1" N-BK7 Ground Glass Diffuser, 1500 Grit, ARC: 650-1050 nm