MWIR Lenses: Achromatic Optics for the 3µm to 5µm Band

Midwave infrared (MWIR) achromatic lenses from Wavelength Opto-Electronic are built for designers and researchers working in the 3µm to 5µm spectral region. The lenses deliver near-diffraction-limited performance, so energy from your source or scene arrives at the detector or sample as a tight, well-corrected spot rather than a smeared one. Whether you’re building an FTIR bench, integrating an MWIR thermal camera, or collimating and focusing the output of a tunable quantum cascade laser, these lenses give you a corrected optical path across the band you’re working in.

Why achromatic correction matters in the MWIR

In the midwave infrared, many applications don’t sit at a single wavelength. FTIR instruments sweep across a broad spectrum. Thermal scenes radiate across the whole band. A tunable QCL moves its output wavelength by design. With an uncorrected singlet, focus shifts as wavelength changes, so you either refocus constantly or accept blur over part of your range.

An achromatic design corrects for that chromatic focal shift across the operating band. The practical result is consistent focus and image quality as wavelength changes, which simplifies system alignment and makes measurements more repeatable.

Applications

• FTIR spectroscopy. Broadband collection and focusing optics for Fourier transform infrared instruments used in analytical chemistry, materials characterization, gas analysis and process monitoring in semiconductor and chemical manufacturing.
• MWIR thermal imaging. Objective lenses for cooled and uncooled MWIR camera systems used in industrial inspection, process temperature monitoring, research and defense-adjacent test and measurement.
• Tunable quantum cascade laser systems. Collimation and focusing optics for QCL-based spectroscopy, trace gas sensing and IR microscopy, where the lens needs to hold focus as the laser tunes.

Selecting the right lens

The MWIR lens catalogue covers a range of parts. The specification table on this page lists each part by wavelength range, focal length, focus type, F-number, back working distance (BWD), mount and compatible detector. When you narrow down a part, consider:

• Detector pairing. Match the lens to your focal plane array or single-element detector so the image circle, mount and back working distance suit your camera or sensor housing.
• F-number. A faster lens collects more radiant energy, which matters for low-signal thermal and spectroscopic work. A slower lens can ease depth-of-focus and alignment requirements.
• Back working distance. Check that the BWD leaves room for windows, filters, cold shields or dewar geometry in your assembly.
• Focus type and mount. Confirm the focus mechanism and mount interface suit how your system will be adjusted and integrated.

If no catalogue part fits, customization is available. Send your specifications through the RFQ form and the engineering team will review what’s needed.

Why buy through Wavelength Optics USA

Wavelength Optics is the US arm of Wavelength Opto-Electronic, the Singapore manufacturer that designs and produces these lenses. Working with the US team gives you:

• Local support. A US-based point of contact in your business hours for questions on parts, documentation and orders.
• Fast quoting. Send a part number or a set of requirements and get a response without routing your request overseas yourself.
• Technical consultation on selection. Talk through detector compatibility, F-number trade-offs, working distance and integration constraints before you commit to a part, or before you request a custom design.

To get started, choose a part from the specification table or describe your application in the RFQ form, and Wavelength Optics USA will follow up.