BP4260-180（4260nm CWL，OD2@400-11000nm，FWHM=180nm）带通滤光片

Carbon Dioxide (CO2) Gas Detection

This filter is perfectly tuned to 4260nm (4.26 micrometers), which is the exact wavelength of invisible infrared light that Carbon Dioxide heavily absorbs. By putting this filter inside an air sensor, the detector only "sees" this specific light. If there is a lot of CO2 in the air, the gas absorbs the light, and the sensor sees a drop in brightness. This is the main technology (called NDIR) used in indoor air quality monitors, smart home ventilation systems, and industrial safety alarms.

• Recommended light source:
• Thermal Infrared Emitters (Micro-heaters): They are inexpensive, reliable, and act like tiny hot plates that naturally give off a broad amount of infrared heat/light for the filter to use.
• Mid-Infrared LEDs (MIR-LEDs tuned to ~4.3µm): They use very little power and can be turned on and off almost instantly, making them perfect for battery-powered, portable smart-home monitors.

Medical Breath Analysis (Capnography)

During surgery, anesthesia, or intensive care, doctors need to monitor exactly how much CO2 a patient is exhaling to ensure their lungs are working correctly. This filter is placed in the breathing tube sensors to precisely count the CO2 levels without getting confused by moisture or other gases in the patient's breath.

Recommended light source:

• High-Speed Mid-IR LEDs: They react incredibly fast, which is necessary to catch the rapid, split-second changes in CO2 levels every single time a person breathes in and out.
• High-Performance Thermal Emitters: They provide a very steady, continuous, and strong beam of light, which is critical for life-saving medical devices that require extreme, unwavering accuracy over many hours.