808nm 대역 통과 필터

Context: This patent describes a portable Raman spectroscopy system designed to detect chemical substances (e.g., toxins, pollutants) by analyzing their molecular vibrations. The system uses a laser diode to excite the sample.

Usage of Filter: The 808nm bandpass filter is used as a Laser Line Clean-up Filter in the laser source module.

Function: Diode lasers often emit low-level "spontaneous emission" (noise) at wavelengths other than the main 808nm peak. The bandpass filter transmits only the sharp 808nm center wavelength and blocks the adjacent spectral noise.

Result: This achieves a high Signal-to-Noise Ratio (SNR). By eliminating the broadband noise from the laser source, the system prevents that noise from overlapping with the weak Raman scatter signals returning from the sample, ensuring accurate chemical identification.

Context: This patent details a fluorescence imaging system operating in the "Second Near-Infrared Window" (NIR-II), which allows for deep tissue imaging with high clarity.

Usage of Filter: The bandpass filter is used as an Excitation Filter within the optical train.

Function: The system uses an 808nm laser to excite specific fluorophores (like carbon nanotubes or quantum dots) inside biological tissue. The filter ensures that the illumination is strictly confined to the 808nm band.

Result: This achieves enhanced image contrast and depth. By strictly confining the excitation light, the system minimizes "autofluorescence" (glowing) from surrounding tissues and ensures that the detector only receives the signal from the targeted fluorophores, allowing for clear visualization of blood vessels or tumors deep under the skin.

Context: This patent focuses on medical imaging of vasculature (blood vessels) and cardiac function using shortwave infrared (SWIR) sensors.

Usage of Filter: The 808nm bandpass filter acts as a Source Conditioning Filter for the diffuse illumination system.

Function: The patent describes emitting "diffuse 808 nm excitation light" towards a beating heart. The filter conditions this light source to prevent spectral broadening that could leak into the detection band (which is typically >1000nm).

Result: This achieves high-speed, real-time angiography. The precise spectral control allows the system to capture video (e.g., 9.7 frames per second) of a beating heart with fine resolution (~30 µm), enabling doctors to see blood flow in real-time without signal interference from the excitation source.