Cooled Mid-Wave Infrared (MWIR) lens
  • Cooled IR Camera

Cooled MWIR Lens | 3–5 µm Mid-Wave Infrared Optics

Cooled Mid-Wave Infrared (MWIR) lenses are precision optical systems engineered for operation in the 3–5 µm spectral range and designed specifically for use with cooled infrared detectors. By working in conjunction with cryogenically cooled sensors, MWIR lenses enable exceptional thermal discrimination, high contrast, and long-range imaging performance.

These lenses are essential for applications that demand fine temperature resolution, long detection distances, and superior image fidelity, where uncooled systems are insufficient.

 

Optical Module Characteristics

  • Optimized for MWIR (3–5 µm) spectral operation
  • Typically manufactured from Germanium (Ge) and other low-dispersion infrared materials
  • Designed to maintain optical focus and alignment at cryogenic temperatures
  • Incorporates thermal compensation mechanisms to counter material contraction during cooling
  • Robust mechanical structure to support the size and mass of cooled detector assemblies

 

Key Optical Parameters

  • Focal Length: Typically 15 mm to 500 mm, depending on field-of-view and range requirements

  • Aperture (F-Number): Customizable; large apertures (e.g. F/1.0–F/2.0) available for maximum sensitivity

  • Spectral Range: 3–5 µm (MWIR)

  • Transmittance: Very high, enhanced by MWIR-optimized anti-reflective coatings

  • Detector Compatibility:

    • InSb (Indium Antimonide)

    • MCT (Mercury Cadmium Telluride)

  • Mount Type: Heavy-duty mounts designed for cooled detector and Dewar assemblies

 

Applications

Cooled MWIR lenses are widely deployed in demanding, high-end applications such as:

  • Long-range surveillance and reconnaissance
  • Military and defense imaging systems
  • Gas detection and leak visualization
  • Flare and combustion monitoring
  • Aerospace and space research
  • High-end scientific and laboratory research

 

How to Choose a Cooled MWIR Lens

Selecting the right MWIR lens requires careful alignment between optical performance and system requirements:

1. Define the Application

  • Operational environment: temperature extremes, dust, moisture, vibration
  • Primary use: surveillance, gas imaging, scientific research, or industrial inspection

2. Select Focal Length & Field of View

  • Short focal length: Wide field of view for situational awareness
  • Long focal length: Narrow field of view for long-range detection and target identification

3. Aperture (F-Number)

A lower F-number (larger aperture) improves thermal sensitivity by allowing more infrared energy to reach the detector—critical for high-resolution and long-range imaging.

4. Match Lens Resolution to Detector

Ensure the lens meets or exceeds the detector’s resolution to avoid limiting image quality, especially for high-resolution cooled sensors.

5. Detector Compatibility

Confirm compatibility with:

  • Detector material (InSb or MCT)
  • Detector size and pixel pitch
  • Dewar and cooler geometry

6. Optical Materials & Coatings

  • Choose materials with excellent MWIR transmission
  • Ensure MWIR anti-reflection coatings are optimized for your wavelength band

7. Mechanical & Environmental Robustness

  • Rigid mechanical housing for vibration and shock resistance
  • Environmental sealing if used outdoors or in harsh conditions

8. Supplier Support & Customization

High-performance MWIR lenses often require:

  • Custom optical design
  • Tight tolerance manufacturing
  • Long-term technical support

9. Budget & Lead Time

Cooled MWIR lenses are premium components. Balance cost with:

  • Performance gains
  • Project timelines
  • Customization requirements