{"title":"Bandpass Filters for CO2 Detection","description":"\u003cp\u003eCO₂ molecules absorb infrared light strongly at specific wavelengths due to their vibrational-rotational energy transitions. The \u003cstrong\u003eprimary absorption band\u003c\/strong\u003e for CO₂ is \u003cstrong\u003earound 4.26 µm (micrometers)\u003c\/strong\u003e. NDIR sensors exploit this property:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003eIR light passes through a gas sample.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eCO₂ molecules absorb light at 4.26 µm, attenuating the signal.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eThe amount of attenuation correlates with CO₂ concentration via the \u003cstrong\u003eBeer-Lambert Law\u003c\/strong\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003eActive Filter (Detection Channel)\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eCentered at the \u003cstrong\u003eabsorption peak\u003c\/strong\u003e of the target gas (e.g., 4.26 µm for CO₂).\u003c\/li\u003e\n\u003cli\u003eMeasures the \u003cstrong\u003eattenuation\u003c\/strong\u003e of IR light caused by the gas absorbing energy.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003eReference Filter (Compensation Channel)\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eCentered at a wavelength \u003cstrong\u003eunaffected\u003c\/strong\u003e by the target gas (e.g., 3.9 µm for CO₂).\u003c\/li\u003e\n\u003cli\u003eProvides a baseline signal to account for \u003cstrong\u003enon-gas-related changes\u003c\/strong\u003e (e.g., light source intensity, dust, or humidity).\u003c\/li\u003e\n\u003c\/ul\u003e","products":[{"product_id":"bp3800-300","title":"BP3800-300 (3800nm CWL, OD2@400-11000nm, FWHM=300nm) Bandpass Filter","description":"\u003cp\u003eThis BP3800-300 is designed to transmit a narrow band around See specification table while reducing out-of-band light. It is suitable for machine vision, fluorescence imaging, and optical inspection systems using wavelength-centered signal detection. It helps isolate the target signal, reduce background light, and improve contrast.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eKey specifications:\u003c\/strong\u003e\u003cbr\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eWavelength \/ main spec: See specification table center wavelength (CWL)\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eBandwidth \/ transition spec: 300 nm FWHM\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eTransmission \/ blocking: T \u0026gt;80%; see specification table for blocking details\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eFormat \/ custom option: Available in 3.3×3.3mm; Custom sizes and mounting options available on request\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"SyronOptics","offers":[{"title":"3800nm \\ 300nm \\ OD2@400-11000nm \/ T＞80% \/ 3.3×3.3mm","offer_id":51041256702235,"sku":"SO3020188-3.3×3.3","price":10.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0759\/8755\/0491\/files\/bp-3800-300-od2-400-11000-nm.svg?v=1778234351"},{"product_id":"bp4260-180","title":"BP4260-180 (4260nm CWL, OD2@400-11000nm, FWHM=180nm) Bandpass Filter","description":"\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eWavelength:\u003c\/strong\u003e 4260nm center wavelength (CWL) for mid-infrared applications\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSpectral Features:\u003c\/strong\u003e FWHM = 180nm bandwidth for precise spectral isolation\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOptical Density:\u003c\/strong\u003e OD2 blocking from 400-11000nm for superior out-of-band rejection\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFilter Dimension Availability:\u003c\/strong\u003e Custom sizes available for research and industrial imaging systems\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"SyronOptics","offers":[{"title":"4260nm \\ 180nm \\ OD2@400-11000nm \/ T＞80% \/ 3.3×3.3mm","offer_id":51041255784731,"sku":"SO3020178-3.3×3.3","price":10.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0759\/8755\/0491\/files\/bp-4260-180-od2-400-11000-nm.svg?v=1778234290"}],"url":"https:\/\/syronoptics.com\/collections\/bandpass-filters-for-co2-detection.oembed","provider":"SyronOptics","version":"1.0","type":"link"}