Magnesium Fluoride Windows

Overview
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Window Guide

Flat Window Selection Guide
Wavelength Range	Substrate Material
150 nm - 5.0 μm	Sapphire
180 nm - 8.0 μm	Calcium Fluoride (CaF₂)
185 nm - 2.1 μm	UV Fused Silica
200 nm - 6.0 μm	Magnesium Fluoride (MgF₂)
250 nm - 1.6 µm	UV Fused Silica, for 45° AOI
300 nm - 3 µm	Infrasil^®
350 nm - 2.0 μm	N-BK7
600 nm - 16 µm	Zinc Selenide (ZnSe)
1.2 - 8.0 μm	Silicon (Si)
2.0 - 16 μm	Germanium (Ge)
3 - 5 μm	Barium Fluoride (BaF₂)
V-Coated Laser Windows

Features

T ≥ 94% for λ = 200 nm to 6 μm
>50% Transmission at 120 nm
Ø1/2" and Ø1" Versions Available

Thorlabs' Magnesium Fluoride windows are available in Ø1/2" and Ø1" sizes. They offer excellent transmission from deep in the ultraviolet region to the mid-infrared. MgF₂ windows are extremely durable and introduce minimal aberrations. Thorlabs' MgF₂ windows are cut with the optical axis parallel to the c-axis of the crystal to minimize birefringence.

MgF₂ windows are well suited for deep-UV applications, even extending into the vacuum-UV region. They offer >50% transmission at 120 nm, making them suitable for use with excimer laser systems, as well as applications involving the Hydrogen Lyman-α line at 121 nm. Thorlabs' MgF₂ windows are also usable in the UVA, UVB, visible and IR ranges, with approximately 94% transmission from 200 - 1000 nm, and approximately 95% transmission from 1 - 6 µm.

Posted Comments:

Enrique Vasco (posted 2020-10-03 15:11:52.777)

Please, could you provide me with data on MgF2 window damage thresholds for 10 ns-pulsed UV laser, as the product description specifies that it is suitable for excimer laser and deep UV applications? Thankx

YLohia (posted 2020-10-07 02:30:18.0)

Thank you for contacting Thorlabs. Unfortunately, we don't test or specify LIDT for bulk optics. Based on your beam parameters (266 nm, 100 mJ, 8 ns, 10 Hz, 3mm) and the literature available online, we expect the WG60530 to not sustain damage, but we cannot provide any guarantees for this at the moment.

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
Sapphire: Flat or Wedged	150 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
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
Magnesium Fluoride (MgF₂): Flat or Wedged	200 nm - 6.0 μm	Uncoated	-	Raw Data	-
Barium Fluoride (BaF₂): Wedged (Flat BaF₂ Windows Available Below)	200 nm - 11 µm	Uncoated	-	Raw Data	-
	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	2.0 - 16 μm	Uncoated	-	Raw Data	-
		-C9 Coating, 1.9 - 6 µm (Only Flat)	R_avg < 2% at 0° AOI	Raw Data	Raw Data
		-G Coating, 7 - 12 µm (Only Flat)	R_avg < 1% 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
Barium Fluoride (BaF₂): Flat (Wedged BaF₂ Windows Available Above)	3 - 5 μm	-E Coating, 3 - 5 µm	R_avg < 2% at 0° AOI	Raw Data	Raw Data