Thorlabs 355390-B Geltech Aspheric Lens

​The Thorlabs 355390-B is an unmounted Geltech aspheric lens designed for applications within the 600 to 1050 nm wavelength range. This lens features a 4.5 mm diameter and an effective focal length (EFL) of 2.75 mm, providing a numerical aperture (NA) of 0.55. The aspheric design effectively reduces spherical aberration, enhancing focusing and collimating accuracy. Constructed from D-ZLaF52LA glass, the lens is coated with an anti-reflective (AR) layer optimized for the specified wavelength range, minimizing reflection losses and improving transmission efficiency. ​

This lens is particularly suitable for applications such as fiber coupling, collimating laser diodes, and laser scanning systems. The aspheric surface ensures high-quality performance by reducing spherical aberrations, which is crucial for maintaining beam quality in these applications. ​