Potassium Bromide Windows

Uncoated KBr Substrate
250 nm - 26 µm Wavelength Range
Ø12.5 mm or Ø25.0 mm Size

WG10123

(Ø12.5 mm)

WG10255

(Ø25 mm)

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Overview
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Window Guide

Flat Window Selection Guide
Wavelength Range	Substrate Material
180 nm - 8.0 μm	Calcium Fluoride (CaF₂)
185 nm - 2.1 μm	UV Fused Silica
200 nm - 5.0 μm	Sapphire
200 nm - 6.0 μm	Magnesium Fluoride (MgF₂)
220 nm to >50 µm	CVD Diamond Windows
230 nm - 1.1 µm	UV Fused Silica, Textured Antireflective Surface
250 nm - 1.6 µm	UV Fused Silica, for 45° AOI
250 nm - 26 µm	Potassium Bromide (KBr)
300 nm - 3 µm	Infrasil^®
350 nm - 2.0 μm	N-BK7
600 nm - 16 µm	Zinc Selenide (ZnSe)
1 - 1.7 µm	Infrasil^®, Textured Antireflective Surface
1.2 - 8.0 μm	Silicon (Si)
1.9 - 16 μm	Germanium (Ge)
2 - 5 μm	Barium Fluoride (BaF₂)
V-Coated Laser Windows

Features

Ø12.5 mm and Ø25.0 mm Versions Available
Uncoated Potassium Bromide
250 nm - 26 µm Wavelength Range

Thorlabs' Potassium Bromide (KBr) Precision Windows are available in Ø12.5 mm and Ø25 mm sizes. Potassium bromide features high transmission across an extremely broad wavelength range as well as high resistance to mechanical shock and temperatures up to 300 °C. However, KBr is water-soluble, so the window should be safeguarded from moisture including high humidity environments. The broad transmission range makes KBr windows excellent for use in FTIR spectroscopy.

When handling optics, one should always wear gloves. This is especially true when working with potassium bromide as any excess moisture can damage the surface.

Thorlabs also offers precision windows fabricated from other substrates for use in a large variety of laser and industrial applications. For our complete selection, see the Flat Window Selection Guide table to the right. We also offer laser windows, which have AR coatings centered around commonly used laser wavelengths, and Brewster windows, which are designed to eliminate P-polarized reflected light.

Item #	WG10123	WG10255
Diameter	12.5 mm	25.0 mm
Diameter Tolerance	+0.0 / -0.1 mm
Thickness	3.0 mm	5.0 mm
Thickness Tolerance	±0.5 mm
Clear Aperture	>Ø11.25 mm	>Ø22.50 mm
Parallelism	<30 arcsec
Surface Flatness	<4λ at 633 nm over Clear Aperture
Surface Quality	60-40 Scratch-Dig
Substrate	Potassium Bromide^a
Transmission Data

Click Link for Detailed Specifications on the Substrate

Posted Comments:
银龙秦 (posted 2024-10-21 06:29:13.583) No ROSH date EGies (posted 2024-10-31 05:09:28.0) Thank you for contacting Thorlabs. I have reached out to you directly regarding the RoHS/REACH documentation for WG10255.

Window Selection Guide (Table Sorted by Wavelength)
Substrate and Window Type	Wavelength Range	Available AR Coatings	Reflectance over AR Coating Range^a	Transmission Data	Reflectance Data
Calcium Fluoride (CaF₂): Flat or Wedged	180 nm - 8.0 μm	Uncoated	-	Raw Data	-
Calcium Fluoride (CaF₂): Flat or Wedged	180 nm - 8.0 μm	-D Coating, 1.65 - 3.0 µm	R_avg < 1.0%; R_abs < 2.0% at 0° AOI	Raw Data	Raw Data
UV Fused Silica: Flat, Wedged, V-Coated Flat, or V-Coated Wedged	185 nm - 2.1 μm	Uncoated (Flat or Wedged)	-	Raw Data	-
		-UV Coating, 245 - 400 nm (Flat or Wedged)	R_avg < 0.5% at 0° AOI	-	Raw Data
		-C3 Coating, 261 - 266 nm (V-Coated)	R_avg < 0.5% at 0° AOI	-	Raw Data
		-C6 Coating, 350 - 450 nm (V-Coated)	R_avg < 0.5% at 0° AOI	-	Raw Data
		-A Coating, 350 - 700 nm (Flat or Wedged)	R_avg < 0.5% at 0° AOI	-	Raw Data
		-B Coating, 650 - 1050 nm (Flat or Wedged)	R_avg < 0.5% at 0° AOI	-	Raw Data
		-C Coating, 1050 - 1700 nm (Flat or Wedged)	R_avg < 0.5% at 0° AOI	-	Raw Data
Sapphire: Flat or Wedged	200 nm - 5.0 μm	Uncoated	-	Raw Data	-
		-D Coating, 1.65 - 3.0 µm	R_avg < 1.0% at 0° AOI	Raw Data	Raw Data
		-E1 Coating, 2.0 - 5.0 µm	R_avg< 1.50%, R_abs< 3.0% (per Surface, 2.0 - 5.0 µm); R_avg < 1.75% (per Surface, 2.0 - 4.0 µm) at 0° AOI	Raw Data	Raw Data
Magnesium Fluoride (MgF₂): Flat or Wedged	200 nm - 6.0 μm	Uncoated	-	Raw Data	-
Barium Fluoride (BaF₂): Flat or Wedged	200 nm - 11 µm	Uncoated (Wedged Only)	-	Raw Data	-
Barium Fluoride (BaF₂): Flat or Wedged	200 nm - 11 µm	-E1 Coating, 2 - 5 µm	R_avg < 1.25%; R_abs < 2.5% at 0° AOI	Raw Data	Raw Data
UV Fused Silica, for 45° AOI: Flat or Wedged	250 nm - 1.6 µm	Coating for 250 nm - 450 nm	R_avg < 1.0% at 45° AOI	Raw Data
		Coating for 350 nm - 1100 nm	R_avg < 2.0% at 45° AOI	Raw Data
		Coating for 400 nm - 700 nm	R_avg < 1.0% at 45° AOI	Raw Data
		Coating for 600 nm - 1700 nm	R_avg < 1.5% at 45° AOI	Raw Data
		Coating for 700 nm - 1100 nm	R_avg < 1.0% at 45° AOI	Raw Data
		Coating for 1200 nm - 1600 nm	R_avg < 1.0% at 45° AOI	Raw Data
Potassium Bromide (KBr): Flat	250 nm - 26 µm	Uncoated	-		-
Infrasil^®: Flat	300 nm - 3 µm	Uncoated	-	Raw Data	-
N-BK7: Flat, Wedged, V-Coated Flat, or V-Coated Wedged	350 nm - 2.0 μm	Uncoated (Flat or Wedged)	-	Raw Data	-
		-A Coating, 350 - 700 nm (Flat or Wedged)	R_avg < 0.5% at 0° AOI	-	Raw Data
		-C7 Coating, 400 - 700 nm (V-Coated)	R_avg < 0.5% at 0° AOI	-	Raw Data
		-C10 Coating, 523 - 532 nm (V-Coated)	R_avg < 0.5% at 0° AOI	-	Raw Data
		-C11 Coating, 610 - 860 nm (V-Coated)	R_avg < 0.5% at 0° AOI	-	Raw Data
		-B Coating, 650 - 1050 nm (Flat or Wedged)	R_avg < 0.5% at 0° AOI	-	Raw Data
		-C13 Coating, 700 - 1100 nm (V-Coated)	R_avg < 0.5% at 0° AOI	-	Raw Data
		C14 Coating, 1047 - 1064 nm (V-Coated)	R_avg < 0.5% at 0° AOI	-	Raw Data
		-C15 Coating, 523 - 532 nm & 1047 - 1064 nm (V-Coated)	R_avg < 0.5% at 0° AOI	-	Raw Data
		-C Coating, 1050 - 1700 nm (Flat or Wedged)	R_avg < 0.5% at 0° AOI	-	Raw Data
Zinc Selenide (ZnSe): Flat or Wedged	600 nm - 16 µm	Uncoated	-	Raw Data	-
		-D Coating, 1.65 - 3.0 µm	R_avg < 1.0%; R_abs < 2.0% at 0° AOI	Raw Data	Raw Data
		-E4 Coating, 2 - 13 µm (Only Flat)	R_avg < 3.5%; R_abs < 6% at 0° AOI	Raw Data	Raw Data
		-E2 Coating, 4.5 - 7.5 µm (Only Flat)	R_avg < 1.0%; R_abs < 2.0% at 0° AOI	Raw Data	Raw Data
		-E3 Coating, 7 - 12 µm (Only Wedged)	R_avg < 1.0%; R_abs < 2.0% at 0° AOI	Raw Data	Raw Data
		-G Coating, 7 - 12 µm (Only Flat)	R_avg < 1% at 0° AOI	Raw Data	Raw Data
Silicon (Si): Flat or Wedged	1.2 - 8.0 μm	Uncoated	-	Raw Data	-
		-E1 Coating, 2 - 5 µm (Only Wedged)	R_avg < 1.25%; R_abs < 2.5% at 0° AOI	Raw Data	Raw Data
		-E Coating, 3 - 5 µm (Only Flat)	R_avg < 2% at 0° AOI	Raw Data	Raw Data
Germanium (Ge): Flat or Wedged	1.9 - 16 μm	Uncoated, 2.0 - 16 μm	-	Raw Data	-
		-C9 Coating, 1.9 - 6 µm (Only Flat)	R_avg < 2% at 0° AOI	Raw Data	Raw Data
		-E3 Coating, 7 - 12 µm	R_avg < 1.0%; R_abs < 2.0% at 0° AOI	Raw Data	Raw Data

Reflectance is given per surface and each window is coated on both sides.