Laser Crystals and Components
UV Optics are optics optimized for applications in the electromagnetic spectrum from 10nm to 400nm, the ultraviolet wavelength range is located above the visible region, and the X-radiation wavelengths. Common UV optics include ultraviolet lenses, windows, optical filters, beam splitters, prisms, and polarizing optical components like waveplates.
To obtain high transmission in the ultraviolet wavelength range, the optical material chosen to manufacture UV optics must have a large bandgap. This is because UV light has photons with higher energy than visible light; these photons can excite electrons in the material from the valence band to the conduction band, which leads to absorption of the photon instead of transmission of UV light. Therefore, dielectric materials with large band gaps, such as CaF2 (calcium fluoride), which prevents the UV photons from exciting electrons and being absorbed, are examples of optical crystals that are transparent in the UV range.
UV optics also require higher surface quality and superior optical homogeneity within the optical media. Even minor defects within the optical material and scratches on the surface of the UV optical components will cause significant scattering of the UV light because of the short wavelengths.
For the ultraviolet spectrum, many optical materials exhibit much greater chromatic dispersion than in the visible or IR range. Therefore, for UV optics, especially those for the use of broadband ultraviolet light source, achromatic design should be taken into consideration.
Damage threshold and degradation are other issues for UV optics, especially in the application context of intense UV lasers. The ultraviolet optics should possess sufficient damage threshold and resistance to long-term exposure to UV radiation. Impurities within the optical material and the surface precision should be strictly controlled as the two are the major determinants of damage and degradation of UV optics.
Deep Ultraviolet (DUV) refers to the short wave UV spectrum, approximately located between 193-248nm, and Vacuum Ultraviolet (VUV) roughly occupies the even shorter UV region between 150-200nm. As the Rayleigh equation suggests, extension into the shorter portion of the UV spectral region helps to exceed the limit on the ultimate resolution that can be obtained, therefore, deep UV and vacuum UV optics and crystal materials serve indispensable roles in various demanding applications that prioritize precision. DUV, VUV optics, and crystals are used in an extensive range of professional domains, including ultraviolet photolithography, excimer lasers (e.g., ArF lasers at 193nm), space and astronomy, and medical treatment (e.g., LASIK surgeries) etc., with enhanced accuracies they offer.
Hangzhou Shalom EO offers a comprehensive range of Custom Deep UV Optics, Vacuum UV Optics, and DUV, VUV Transparent Optical Crystals to cater to the demands of high-performance optical systems. We specialize in manufacturing crystals that transmit the ultraviolet wavelength range, The crystals are excellent as substrate (or coating) materials for UV, deep UV, and vacuum UV optics. Finished UV optical components with optional coatings are also available.
Our main crystal types include: UV grade calcium fluoride (CaF2) optics and crystals, magnesium fluoride (MgF2) optics and crystals, and lithium fluoride (LiF2) optics and crystals, CLBO crystals, accommodating to applications in the deep ultraviolet, vacuum ultraviolet, and ultraviolet wavelengths, while we can also provide different grades as being flexible for applications in the VIS and infrared region. Our duv and vuv grade CaF2, MgF2, and LiF2 crystals, grown via a state-of-the-art high purification process, exhibit leading-edge excellence with their large aperture sizes, low bubble/inclusion content, superior laser damage/UV radiation resistance, high UV transmittance, and outstanding refractive index uniformity. Apart from bulk CaF2, MgF2, and LiF2 crystals, Shalom EO provides high-precision ultraviolet optics made of fluorides with well-maintained surface flatness and surface quality to meet the most stringent requirements. Our deep UV and vacuum UV fluoride optics are available in various specifications and types, including circular, square, and stepped windows; lenses; prisms; mirrors; beamsplitters; waveplates; and custom-shaped optical elements, all tailored to customer specifications. Various coating options, such as AR coating or HR coating, are available.
With efficient production capacities, Hangzhou Shalom EO is well-equipped to support large-scale customer demands for deep UV, vacuum UV optics, and crystal materials and components, where we also utilize advanced testing equipment and adhere to rigorous quality assurance standards to deliver CaF2, MgF2, LiF2 crystals and materials that exceed expectations in functionalities and quality.
Below is a brief guide to our deep UV, vacuum UV optics and crystals:
Calcium Fluoride (CaF2) Optics and Crystals:
Shalom EO CaF2 crystals are grown using the Bridgman-Stockbarger method. Calcium fluoride crystals, with their dominant comprehensive advantages of low chromatic dispersion, high damage threshold, and high refractive index uniformity, in addition to being harder than other fluorides, are the most popular optical material to make UV optics such as 193nm (ArF) excimer laser focusing lenses. We can provide coated or uncoated CaF2 lenses/windows/prisms/beamsplitters, etc.
Magnesium Fluoride (MgF2) Optics and Crystals:
Shalom EO’s MgF2 crystals are grown using the Bridgman-Stockbarger method. Magnesium fluoride crystals and optics, in comparison with CaF2 optics, MgF2 crystals, and optics have better deep UV transmittance and short cut-off wavelength at approximately 121nm. MgF2 also has more beneficial physical and chemical properties. However, it is slightly birefringent. We can provide coated or uncoated MgF2 lenses/windows/prisms/beamsplitters/waveplates/optical filters, etc.
Lithium Fluoride (LiF) Optics and Crystals:
Shalom EO’s LiF crystals are mainly grown using the Bridgman-Stockbarger method, but can also be grown using the Kyropoulos (KY) method for better microstructure. LiF crystals and optics have the highest transparencies for deep UV wavebands with a cut-off wavelength below 110nm. However, LiF is hygroscopic and is a potential victim of cleavage along the (100) or (110) plane. We provide coated or uncoated LiF windows/lenses/apochromatic lenses/optics for X-ray spectrometers.
CLBO Crystals:
CLBO is an excellent nonlinear optical crystal material for producing UV and deep-ultraviolet lasers via harmonic generation. Cesium lithium borate is ideal for FHOG and FIHG for Nd: lasers, SHG and THG for Ti:Sapphire and Alexandrite lasers.
