Custom Infrared Lenses

Infrared (IR) lenses are optical lenses that use specific substrates or anti-reflective coatings to maximize performance for applications operating above 700 nm, including thermal imaging, FLIR or spectroscopy. Alfa Chemistry offers a wide range of custom IR lenses for focusing, collimating and collecting light in the near IR (NIR), shortwave IR (SWIR), midwave IR (MWIR) and longwave IR (LWIR) spectra. Different IR optical materials are used to create our unique infrared lenses. To lessen aberrations within the system, we provide cylinder, plano-convex/concave, and curved-moon lenses, as well as achromatic bifocal lenses and aspheric alternatives.

We produce high performance IR lenses to satisfy our clients' requirements for industrial, medical, life science, and defense applications by upholding the highest production and standards. In our state-of-the-art metrology lab, our highly qualified personnel test each product to make sure it complies with requirements. For more information on your custom IR lense needs, please contact our technical sales team.

Our Capabilities

Alfa Chemistry offers its customers IR lenses made of the following IR materials.

Custom Fluoride Lenses

Alfa Chemistry offers a variety of custom fluoride lenses including calcium fluoride (CaF₂), barium fluoride (BaF₂), and magnesium fluoride (MgF₂).

• Calcium Fluoride - Due to the material's broad transmission range of 0.13 µm to 10 µm and good refractive index uniformity, custom CaF₂ lenses are employed for IR applications. They are perfect for FLIR systems because of their stability and transmission characteristics.
• Barium Fluoride - Custom BaF₂ lenses offer similar transmittance to CaF₂.
• Magnesium Fluoride - With a coverage range of 0.12 µm to 7 µm, custom MgF₂ lenses have a somewhat smaller transmission range. It is an IR substance that is more robust.

Custom Germanium (Ge) Lenses

High IR transmission and a high refractive index characterize custom Ge lenses. Uncoated Ge has a transmittance of roughly 45%, hence they are frequently coated with AR/AR or AR/DLC coatings to increase their transmittance and lens longevity. Broadband anti-reflective (BBAR) coatings are frequently employed in the 7~14 µm range to boost LWIR transmittance. DLC coatings exhibit characteristics that are similar to those of diamond and can therefore offer surfaces for their applications greater hardness and corrosion resistance.

Custom Silicon Lenses

Use of a bespoke silicon lens in MWIR laser systems is perfect. To avoid absorption inside certain transmission bands, it is often doped. Silicon is a very strong IR material for lens systems since it is both lightweight and extremely robust.

Custom Zinc Selenide (ZnSe)

The low IR absorption of ZnSe, particularly at 10.6 µm, makes it a popular material for CO₂ laser systems. A transmission-enhancing film can be used to further boost the device's transmission, which ranges from 0.6 µm to 21 µm and averages 70%.

Other IR Materials

Other IR materials we use for custom applications include: sodium chloride, potassium chloride/potassium bromide, gallium arsenide, cesium iodide, etc.

Coatings

To maximize your transmission output, all of our lenses can be coated with particular AR coatings for various wavelengths, including NIR, SWIR, MRIW, and LWIR areas.

Fig 1. Infrared transmission spectra of 2-mm-thick Ge_27.5Sb_12.5SxSe_60-x glasses. (Sang Y.S, et al. 2020)

Quality Assurance

Each custom IR lense is carefully tested to all applicable standards using state-of-the-art metering equipment. We inspect and scrutinize every product before it's shipped to customers, so customers can have complete confidence that the optics they order will be the best fit for their application.

Alfa Chemistry is always looking to expand and work with customers to achieve their specifications, so please feel free to contact our technical sales team for more information and guidance on your enquiry.

Reference

1. Sang Y.S, et al. (2020). "Structural Evolutions of Mixed-Chalcogen Ge-Sb-S-Se Glasses for Use as Infrared Lenses." Ceramics International. 46(11): 17809-17817.