Chalcogenide Lenses for Mid-Infrared Optical Systems

Chalcogenide lenses from Wavelength Optics are made from chalcogenide glass for mid-infrared optical systems. The material transmits across a wide band, from 0.5μm to 25μm, and combines a low refractive index temperature coefficient (dN/dT) with low dispersion. If you’re specifying IR optics and want an alternative to germanium or zinc selenide, chalcogenide gives you comparable optical function with production and supply advantages.

Why chalcogenide glass

Germanium and zinc selenide have long been the default materials for IR optics, but both carry costs. Germanium is a scarce resource, and conventional IR crystal processing limits how efficiently lenses can be produced. Chalcogenide glass addresses both points. Because it is a glass rather than a crystalline material, it allows higher production efficiency, which lowers production cost and reduces consumption of scarce materials like Ge.

The optical properties matter just as much as the economics:

• Wide transmission range. Coverage from 0.5μm to 25μm means a single material family can serve designs spanning the visible edge through the mid- and long-wave infrared.
• Low dN/dT. A low refractive index temperature coefficient means focus shifts less as ambient temperature changes. This simplifies athermal design and reduces the need for active refocusing in systems that operate outside a controlled lab environment.
• Low dispersion. Lower chromatic spread across the band helps you hold image quality without adding correction elements.
• Versatile glass compositions. Chalcogenide can be formulated in different compositions, giving designers more options when balancing index, dispersion and thermal behavior in a multi-element system.

Selecting a lens from the catalogue

The chalcogenide range is catalogued by the parameters you’ll work with during system design: wavelength, focal length, f-number, focus type, athermalization, the detector the lens is matched to, and weight. The full specification table on this page is searchable, so you can filter to the parts that fit your optical path and mechanical envelope.

A few considerations when narrowing the list:

• Detector matching. Start from your sensor. Matching the lens to your detector format and pixel pitch avoids paying for resolution the sensor can’t use, or losing performance at the edge of the field.
• Athermalization. If your system will see temperature swings, check whether an athermalized design is listed. Chalcogenide’s low dN/dT already helps here, and an athermalized assembly carries that further.
• Focus type. Decide early whether a fixed or adjustable focus suits your assembly and calibration process.
• Weight. For handheld, gimbal-mounted or moving-platform equipment, compare weight across candidates with similar optical performance.

If no catalogue part fits, custom designs are available. Specifications and lead time for custom work are confirmed by quotation.

Buying through Wavelength Optics USA

Wavelength Optics is the US arm of Wavelength Opto-Electronic, the Singapore-based precision optics manufacturer that produces these lenses. Working through the US entity gives you:

• Local support. You deal with a team in your region and time zone, which makes it easier to resolve questions during design reviews and procurement.
• Fast quoting. Send your requirements and we’ll turn around a quotation for catalogue or custom parts, including specifications and lead time.
• Technical consultation on selection. Whether you’re moving an existing design off germanium, building a new IR imaging module, or trying to reduce thermal focus drift, our engineers can help you weigh chalcogenide against other IR materials and choose a lens that fits your detector and operating conditions.

To get started, use the Request for Quotation form with your wavelength band, detector, focal length and any environmental requirements, and we’ll follow up with options.