1940nm IR Band pass Filter for Sensing

1940nm IR Band pass Filter for SensingFocusing on the strong liquid-water absorption near 1.94 µm, this filter facilitates applications in moisture imaging, medical laser delivery sampling, and atmospheric column analysis. Thulium-fiber lasers emit around 1940 nm, where water exhibits shallow penetration—making this wavelength suitable for precise tissue ablation. The same spectral band is also valuable for environmental sensing due to the pronounced near-infrared (NIR) overtone of water absorption. Standard InGaAs cameras typically operate within the range of ~0.9–1.7 µm; however, extended-range InGaAs detectors (up to 1.9–2.2 µm) or other shortwave infrared (SWIR) sensors are recommended for optimal performance in this region. Substrates such as UV-grade fused silica maintain transmission up to approximately 2.1 µm, and careful management of the angle of incidence (AOI) prevents passband blue-shift in tilted configurations. Anti-reflective (AR) coatings enhance optical throughput by…

Cut Off Type Glass Selective Absorption Glass Band Pass Filter