Calcium Fluoride (CaF2) Windows
Calcium fluoride (CaF₂) optical windows from MachinedQuartz offer broad infrared transmission from 0.13µm to 10µm, making them the standard choice for FTIR spectroscopy, CO₂ laser optics, and mid-IR imaging systems.
Infrared Transmission
CaF₂ transmits over 90% from 0.35µm to 7µm with no coating, and remains useful to 10µm. Its low refractive index (n=1.43 at 3µm) results in minimal Fresnel reflection losses without AR coating, simplifying optical system design.
Chemical and Mechanical Properties
Calcium fluoride is slightly water-soluble (avoid prolonged exposure to humidity) and cleaves along the (111) plane. It is resistant to most acids and organic solvents. Knoop hardness of 158 makes it moderately durable for spectroscopy cell windows and laser optics.
Available Configurations
Standard diameters φ10mm–φ76.2mm (3 inches), thickness 1–10mm. Rectangular windows available. AR coating (V-coat, BBAR, or broadband) available on request. All windows supplied double-side polished to λ/4 flatness as standard.
Applications
FTIR spectrometer sample cell windows, CO₂ laser output couplers and beam splitters, mid-IR detector windows, cryogenic IR imaging systems, liquid cell windows for IR spectroscopy of aqueous samples.
