Definition of infrared coatings

Meadowlark Optics - Wave Plates 6/24 LB 2024

Photonics Dictionary

infrared coatings: Infrared coatings, also known as IR coatings, are specialized optical coatings designed to manipulate the transmission, reflection, and absorption of infrared (IR) radiation within a specific wavelength range. These coatings are applied to optical components such as lenses, windows, mirrors, and filters to enhance their performance in IR applications.

Transmission and reflection control: IR coatings are engineered to control the transmission and reflection of IR radiation within targeted wavelength bands, typically ranging from near-infrared (NIR) to long-wave infrared (LWIR). They can enhance transmission for IR transmitting optics or increase reflectivity for IR reflective surfaces.

Spectral range: IR coatings are tailored to operate effectively within specific IR wavelength ranges, such as NIR (700 nm to 1.4 µm), mid-wave infrared (MWIR, 3 µm to 5 µm), and LWIR (8 µm to 14 µm). Different materials and designs are used to optimize performance across these wavelength bands.

Functionality: IR coatings serve various functions depending on their application, including anti-reflection (AR) coatings to minimize surface reflections, bandpass filters to transmit specific IR wavelengths while blocking others, and dichroic coatings to separate IR radiation into different spectral bands.

Materials and deposition methods: IR coatings are typically made from materials such as metals (e.g., gold, silver), dielectrics (e.g., zinc sulfide, germanium), or a combination thereof. They are deposited onto optical substrates using techniques like vacuum deposition (thermal evaporation, sputtering) or chemical vapor deposition (CVD).

Applications: IR coatings find extensive use in various fields, including thermal imaging systems, IR spectroscopy, remote sensing, military and defense applications (night vision, targeting systems), medical imaging (IR microscopy), and industrial process monitoring.

Overall, infrared coatings are critical for optimizing the performance and efficiency of optical components in IR applications, enabling enhanced detection sensitivity, signal-to-noise ratio, and spectral selectivity in both imaging and non-imaging systems operating within the infrared spectrum.

Bristol Instruments, Inc. - 872 Series LWM 10/24 MR