Collection: 785nm
A 785nm bandpass filter transmits light primarily around the wavelength of 785 nanometers (nm) while significantly blocking other wavelengths. Like its counterparts at 800nm and 850nm, it acts as a gatekeeper, allowing only specific "colors" of light to pass through freely. Here's a breakdown of its functions and potential applications:
Function:
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Passes light close to 785nm: Typically with high efficiency (e.g., 90% or more).
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Blocks light: Significantly at wavelengths shorter or longer than 785nm.
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Bandwidth (FWHM): Defines the range of transmitted wavelengths around 785nm. Narrower bandwidth offers higher selectivity but lower overall transmission.
Applications:
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Night vision: Although less common than 850nm, 785nm falls within the near-infrared (NIR) spectrum and can be used for covert illumination in some night vision devices. However, its visibility might be slightly higher than 850nm in certain lighting conditions.
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Machine vision: Similar to 800nm and 850nm, used in NIR cameras for:
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Inspecting objects where visible light might be obscured or create glare.
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Identifying specific materials based on their NIR reflectance properties, with potential applications in food inspection, pharmaceutical analysis, and semiconductor manufacturing.
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Fluorescence microscopy: Can be used to isolate specific fluorescent emissions excited by 785nm light, but the availability of suitable fluorophores might be limited compared to longer wavelengths like 850nm.
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Raman spectroscopy: 785nm lasers are commonly used in Raman spectroscopy due to their good balance between penetration depth and reduced fluorescence interference. Bandpass filters at 785nm can block the laser line and unwanted scattered light, enhancing the Raman signal for clearer analysis.
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LiDAR: Similar to 800nm and 850nm, used in lasers for distance measurement and 3D imaging. However, atmospheric scattering is slightly higher at 785nm compared to 850nm, which might affect performance in some scenarios.
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Face recognition: Similar to 800nm and 850nm, cameras with 785nm illumination can capture facial features in low light, but visibility concerns make them less common.
