Calcium Fluoride Window
Calcium fluoride has extremely low bulk absorption and exceptionally small thermal lensing coefficient and high damage threshold, making these windows a good choice for using in free-space lasers. It is adorned with various useful optical properties such excellent ultraviolet (UV) transmittance; a high laser-damage threshold; low axial and radial-stress birefringence; and high refractive-index homogeneity. It provides low dispersion and low fluorescent are, as well as excellent water, chemical, and heat resistance. It can be used up to 1000 °C in dry environment; however in the presence of moisture, degradation will occur for temperatures exceeding 600 °C. It is also popularly used as UV optical material for integrated circuit lithography in beam delivery, illumination and projection systems. It is used in a variety of infrared (IR) and UV applications as it is highly trans missive in these wavelength regions and has an extremely low birefringence.
Also, it is physically alert and chemical inert, which results into making high resistant optical windows. There are calcium fluoride optical windows transparent from 180 nm to 8 µm, ideal for applications such as spectroscopy or fluorescence imaging in the UV, visible, and IR wavelengths.
Magnesium Fluoride Window
Magnesium Fluoride windows have excellent transmission from deep in the ultraviolet region to the mid-infrared. These are extremely durable and provide minimal aberrations. These windows are ideal for deep-UV applications as well as to use with exciter laser systems, and applications involving the Hydrogen Lyman-α line. Magnesium Fluoride Window is popularly used in UVA, UVB, visible and IR ranges as they have excellent transmission in the UV reaching transmission greater that 50% at 121.6nm.
Optical Windows are typically available in a variety of sizes, so one can buy it as per their exact requirements. They should be chosen on the basis of the material transmission or mechanical properties of the substrate. They don’t bring any change in the magnification of a system. It is important or to have a good understanding of your application and optical characteristics, to procure the perfect window at competitive prices.
