Infrared Optics
Infrared windows, or IR windows for short, or sometimes called IR glass windows, in the most general sense, are transparent optical components that allow infrared radiation to pass through with minimal attenuation and distortion, ensuring that the signal received by the rear optics and sensors remains intact. This means that IR windows are not designed to converge, diverge, or reflect IR radiation, but to simply allow the desired IR spectrum to pass through while also acting as a barrier to protect other sensitive and fragile elements from the surrounding environments. IR windows safeguard delicate optical components from contaminants such as dust, moisture, and chemicals, which could degrade performance or cause damage. Therefore, when manufacturing infrared windows, one takes the optical transmission wavelength range, mechanical robustness, and other physical and chemical performance, such as thermal expansion and chemical resistance, into consideration. Many infrared windows are engineered to withstand harsh indoor or outdoor environmental conditions, including temperature extremes, humidity, and pressure variations, without compromising infrared transparencies.
Typically, there are three applicational IR wavelength ranges: long-wave infrared (LWIR), which is defined as the spectral region of 8μm to 12μm (or even extending to 14μm), mid-wave infrared (MWIR), which is the wavelength range between 3 μm to 5 μm, and short-wave infrared (SWIR) , which is the wavelength range from 0.9μm to 1.7μm. The LWIR and MWIR windows are often optimized for thermal imaging cameras.
The choice of IR window materials is manifold, common examples include germanium (Ge), zinc selenide (ZnSe), chalcogenide glass, silicon (Si), calcium fluoride (CaF2), sapphire, etc. Germanium is the most popular IR glass window substrate material with its broad IR transmission range, working well both in the MWIR and LWIR wavelengths. ZnSe is recommended for thermally demanding conditions. Chalcogenide glass is moldable and low-cost. CaF2 features multi-spectrum transmission spanning UV, VIS, and IR wavelengths and has a short UV cut-off wavelength down to 180nm. Sapphire IR glass windows have unparalleled hardness and optical transmission between 150-5500nm.
Infrared windows are used across diverse fields where the manipulation and detection of infrared radiation are crucial, including thermal imaging, remote sensing, defense, and industrial processing.
IR windows find extensive usage in applications like FTIR spectrometers (Fourier-transform infrared), where the infrared windows made using low-absorption materials in the mid-to-far IR ranges in FTIR devices must transmit a broad range of IR wavelengths, allowing the IR light to pass through the sample and into the detector; FLIR imaging (forward-looking infrared), where the IR windows are incorporated into thermal imaging cameras for surveillance, targeting, or navigation of civilian aircraft and medical equipments. IR windows can also be used as view windows in industrial process monitoring (e.g., infrared viewing windows allow infrared cameras to observe high-temperature processes without damage and inspection of energized equipment).
A dominant application direction of infrared windows is IR windows for switchgear, which are durable optical portals installed on the panels of electrical switchgear enclosures. Because thermal imagers can not see through metal panels, the IR transparent windows are critical, as the IR glass windows permit technicians to use thermal imaging cameras to inspect internal components without opening the panel, helping to prevent arc flash incidents, downtime, and exposure to live equipment. Infrared windows for switches consist of a metal or plastic frame that holds the infrared transmissive window element, and a protective cover for the IR window element.
Hangzhou Shalom EO offers off-the-shelf and custom infrared windows that operate at a wide wavelength range made of various substrate materials for selection: germanium (Ge), chalcogenide glass, silicon (Si), zinc selenide (ZnSe), sapphire (Al2O3), calcium fluoride (CaF2), barium fluoride (BaF2), zinc sulfide (ZnS), etc. AR coating options include broadband anti-reflection coating (BBAR), long-pass anti-reflection coating, and hard diamond-like carbon (DLC) coating to withstand harsh environments can be deposited. Our infrared windows are ideal for diverse applications like thermal imaging, gas detection sensors, aerospace optics, and medical diagnostic optics. We also provide assembled IR inspection windows for switchgear.
As an advanced and experienced supplier of IR windows, Shalom EO is capable of offering large-sized, high-quality, durable IR windows.
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