How to select most suitable IR materials for your application?



There are various IR materials available in the market, it’s important to select the most suitable material to fit your application requirements. Following are the comparision between difference IR materials, Hope they will help you on the IR materials selection.


Sapphire crystal (Al2O3)

Sapphire is an optimal choice due to its mechanical strength, scratch resistance, and its hardness which is second only to diamond. It is used in ultraviolet (UV) and visible wavelengths beginning around 150nm and also performs well in IR to around 5µm. sapphire IR optics offer exceptional optical and mechanical properties, making them a popular choice for infrared applications that require high performance, durability, and reliability.


Germanium (Ge) 

Ge has broad transmission range (2.0-16μm) and opacity in the visible portion of the spectrum. It is an optimal material for night vision and thermal imaging systems in the MWIR and the LWIR band. Ge has a low optical dispersion and a high refractive index which makes it an ideal solution for a wider field of view lenses. Its crystal structure is similar to diamond and when a DLC coating is applied (Diamond Like Carbon), it becomes very durable against outdoor elements and harsh environments.  


Calcium fluoride (CaF2) 

CaF2 are ideal for a broad range of Ultraviolet (UV), Visible, or Infrared (IR) applications. Its low refractive index reduces the need for anti-reflective coatings. Its application ranges from thermal imaging systems to excimer lasers making it a very versatile material for ultraviolet (UV) to infrared (IR) frequencies.  


Magnesium fluoride (MgF2)

MaF2 is a synthetic crystalline substrate, transparent over a wide range of wavelengths. Transmitting from 200 nm to 6.0 µm.magnesium fluoride is well suited for applications ranging from the UV to the IR. MgF2 is very rugged and durable, making it useful in high-stress environments. MaF2 is commonly used in laser systems, vacuum viewports etc.


Silicon (Si)

Si lenses and windows are an ideal choice for applications using wavelengths in the near-IR range and parts of the mid-IR range. Silicon offers high thermal conductivity and low density, making it suitable for laser mirrors. However, since silicon has a strong absorption band at 9 µm, it is not suitable for use with CO2 laser transmission applications. Silicon optics are also particularly well suited for imaging, biomedical, and military applications. Silicon has a transmission range from 1.2 µm to 8.0 µm. Silicon has a refractive index of 3.423 at 4.58 µm. 


Zinc selenide (ZnSe)

ZnSe is useful in a wide variety of applications, from infrared radiation collection to laser cutting. The spectral response of ZnSe makes it a particularly good substrate for CO2 laser optics. These optics offer high transmission in the visible range to well past 10 microns, produce good results at 10.6μm and are easily visually aligned. This is a typical of other substrates designed for this region. Economically priced, plano-convex lenses are ideal for use in laser cutting and welding, as well as other applications where spot size and image quality are not as critical. 


Zinc Sulfide (ZnS) 

ZnS performs best between 8 to 12µm region. Although a lower cost relative to ZnSe, it does not have the longer transmission range. As a strong and stable material, ZnSe has high resistance to particulate abrasion making it an ideal solution for IR windows on aircraft platforms.