Zinc Sulphide optical windows, infrared optics

Zinc Sulfide (ZnS): A Versatile Optical Material with Infrared Applications

Zinc sulfide (ZnS) is a prominent optical material celebrated for its versatile properties and broad range of applications. Known for its exceptional transparency across wavelengths, particularly in the visible spectrum and infrared regions, ZnS stands out as a cornerstone in advanced optical technologies.

In the field of optics, ZnS is extensively utilized in critical components such as lenses, optical windows, and prisms. It plays a pivotal role in infrared optics, finding applications in thermal imaging systems, infrared cameras, night vision devices, and laser systems. The multispectral variant of ZnS, appreciated for its enhanced infrared transmission properties, is a preferred choice in these high-precision technologies.

The manufacturing processes for ZnS, including chemical vapor deposition (CVD) and physical vapor deposition (PVD), ensure the production of uniform, high-quality ZnS films and coatings. These techniques offer precise control over thickness and composition, vital for ensuring performance in optical systems.

Despite its outstanding optical capabilities, ZnS is relatively soft, making it susceptible to scratches and damage. Therefore, careful handling and the implementation of protective coatings or measures are essential to preserve the integrity of ZnS-based optical components.

In summary, zinc sulfide (ZnS) is an indispensable optical material, offering remarkable transparency, compatibility with advanced manufacturing techniques, and widespread application in infrared optics. Its critical role in modern optical systems underlines its importance in cutting-edge technologies.

Zinc Sulphide optical windows (ZnS) are a highly valued infrared material recognized for its exceptional technical properties and widespread use in advanced optical systems. With a broad transmission range spanning from 0.37 to 13.5 μm, ZnS exhibits a refractive index of 2.20084 at 10 μm and a reflection loss of 24.7% for two surfaces at this wavelength. Its absorption coefficient varies across wavelengths, measuring 0.2 cm⁻¹ at 10.6 μm, 0.006 cm⁻¹ at 9.27 μm, 0.0006 cm⁻¹ at 3.8 μm, 0.0001 cm⁻¹ at 2.7 μm, and 0.0006 cm⁻¹ at 1.3 μm. Additionally, the material has a Reststrahlen peak at 30.5 μm and a thermo-optic coefficient (dn/dT) of +38.7 × 10⁻⁶ /°C at 3.39 μm.

ZnS has a density of 4.09 g/cc and a melting point of 1827°C, alongside thermal conductivity measured at 27.2 W m⁻¹ K⁻¹ at 298 K. It demonstrates a thermal expansion coefficient of 6.5 × 10⁻⁶ /°C at 273 K and a Knoop hardness of 240 when tested with a 50g indenter. Its specific heat capacity stands at 515 J Kg⁻¹ K⁻¹, and the material has a dielectric constant of 88. Mechanical properties include a Young's Modulus of 74.5 GPa, elastic coefficients of C₁₁ = 89.2, C₁₂ = 40.0, and C₄₄ = 25.4, as well as an apparent elastic limit of 26.9 MPa (3900 psi) and a Poisson's ratio of 0.28. ZnS’s solubility is noted as 65 × 10⁻⁶ g/100g water, and it has a molecular weight of 97.43. Structurally, the material is classified as HIP polycrystalline cubic with an F42m symmetry.

These technical characteristics make Zinc Sulfide an indispensable material for a range of optical and infrared applications. Its exceptional transparency and adaptability to precise manufacturing processes ensure its suitability for high-performance technologies such as thermal imaging, infrared sensors, and optical coatings. While these properties are typical, variations may occur depending on the specific grade and manufacturing techniques employed.