Thorlabs C037TME-F Mounted Geltech Aspheric Lens

📌 Overview

• Part number: C037TME‑F

• Description: Mounted Geltech aspheric lens with anti‑reflection (AR) coating for the 8–12 µm (long-wave infrared) band

• Effective focal length: 1.873 mm (at design wavelength ~9.5 µm)

• Numerical aperture (NA): 0.85

• Clear aperture / Housing size: ~4.00 mm clear aperture within a ~9.24 mm OD housing

• Working distance (mounted): ~0.34 mm

• Substrate material: Black Diamond™‑2 (a chalcogenide glass with good thermal and IR performance)

• Design wavelength: ~9.5 µm ● Coating range: 8–12 µm with average reflectance <1%

• Mount threading: M9 × 0.5 spindle engraved with the part number

• Surface quality: 80‑50 scratch‑dig; Diffraction-limited from ~4.2 to 15 µm wavelength

• Operating temperature: Stable up to ~130 °C due to substrate thermal stability

🧮 Performance & Applications

This lens is ideal for collimating or focusing mid‑ to long‑wave infrared sources (e.g. QCLs, thermal emitters, IR fiber coupling).

With a very high NA (0.85) and short focal length (~1.87 mm), it can deliver near diffraction‑limited performance across the 4.2–15 µm range. It’s commonly used for IR beam coupling, spatial filtering, and imaging onto detectors.