Material Description
Magnesium Fluoride (MgF2) is a highly durable synthetic crystalline material known for its exceptional optical properties across a broad spectrum of wavelengths, from the deep ultraviolet (UV) to the mid-infrared (IR). Its transparency extends from 120 nm to 6.0 µm, making it a versatile material suitable for a wide range of demanding optical applications. MOK Optics specializes in providing high-quality UV-grade MgF2 optical windows, designed to meet the needs of both commercial and scientific industries.
Optical and Mechanical Properties
Broadband Transmission
MgF2 is known for its excellent transmission characteristics. It offers greater than 90% transmittance in the range of 0.4 µm to 5.0 µm, and continues to transmit efficiently across the UV (120 nm) to IR (8 µm) spectrum. This makes it an ideal choice for applications requiring high transmission of UV and IR light, including UV radiation sources, detectors, and laser systems.
Birefringence
MgF2 exhibits inherent birefringence, meaning the material has different refractive indices depending on the polarization and direction of light propagation. This property causes double refraction, where a single incident light ray is split into two components with distinct paths, referred to as the fast and slow rays. The slow ray is refracted more strongly towards the normal of the surface, while the fast ray is refracted less. This characteristic makes MgF2 valuable for specialized optical applications such as polarizers and beam-splitters, but also requires careful consideration in systems where birefringence could affect performance.
High Laser Damage Threshold
MgF2 features a high threshold for laser damage, which allows it to perform reliably in high-power laser systems, including excimer laser setups. This quality is a significant advantage for industries requiring optical components that can withstand high-intensity light without degradation.
Durability
MgF2 is a hard material with excellent resistance to thermal and mechanical shock. It is chemically inert and highly resistant to corrosion, ensuring reliable performance even in harsh environments. This makes it well-suited for applications in extreme conditions, such as space telescopes, high-energy lasers, and optical instrumentation exposed to fluctuating temperatures and abrasive conditions.
Melting Point and Density
With a high melting point of 1255°C and a density of 3.177 g/cm³, MgF2 is a robust material capable of withstanding high thermal stresses. The material is stable even under elevated temperatures, contributing to its reliability in demanding applications.
Custom Manufacturing Options
MOK Optics offers custom fabrication of MgF2 optical windows to meet specific requirements. We provide optical windows with various orientations, including <001>, <100>, and <110>, as well as custom random cuts. Our standard window size can reach up to 170 mm in diameter, with the round surfaces oriented perpendicular to the c-axis of the MgF2 crystal to minimize birefringence effects. We also support custom geometries and sizes upon request.
Applications Of MgF2 Optical Windows
MgF2 optical windows are commonly used in a variety of applications, including but not limited to:
UV and IR Optics: MgF2 optical windows are frequently used in systems that require high transmittance in both UV and IR regions, such as UV spectroscopy, high-power laser systems, and IR imaging.
Excimer Lasers: Due to their high laser damage threshold and optical transparency, MgF2 optical windows are ideal for excimer laser applications where precise control over the light path is crucial.
UV Viewports and Polarizers: MgF2 optical window is often used for UV-viewports and polarizers, offering high transmission in the UV spectrum and high resistance to chemical etching, making it well-suited for harsh chemical environments.
Hydrogen Lyman-alpha Line Applications: MgF2 optical window is particularly effective at transmitting the hydrogen Lyman-alpha line, making it an excellent choice for applications in astrophysics and plasma research.
Handling Considerations: While MgF2 optical window is the hardest of the optical fluorides, it is still softer than fused silica, so care must be taken during handling to avoid scratching or damaging the surface. Protective coatings and proper storage can help maintain the integrity of the material during transportation and assembly.
Conclusion
MgF2 optical windows by MOK Optics provide excellent performance across a wide spectral range, with superb transmission, high resistance to damage, and unique birefringent properties. Whether you are developing high-performance UV or IR optical systems, our MgF2 windows offer the reliability, durability, and customizability needed to meet the most demanding optical requirements.