1653nm SWIR Band Pass Filter for Methane

1653nm SWIR Band Pass Filter for MethaneDesigned for CH₄ detection, this filter allows transmission of the ~1653.7 nm absorption line within methane’s 2ν₃ band, which is commonly utilized in TDLAS systems employing DFB lasers. The spectral line is well-established in HITRAN-based instrumentation, making it a de facto standard; recent research from NIST has further refined its intensity parameters to enhance measurement accuracy. When this bandpass filter is used in conjunction with a wavelength-stabilized DFB laser near 1653.72 nm and either a standard or extended-range InGaAs detector, parts-per-million (ppm) level sensitivity can be achieved through direct or harmonic absorption methods. To maintain the integrity of the center wavelength, the mechanical design should limit the angle of incidence (AOI), while anti-reflection (AR) coatings should be applied to maximize optical throughput. This configuration is extensively employed in applications such as gas leak detection, environmen…

Cut Off Type Glass Selective Absorption Type Glass Band Pass Filter