The 633 nm notch filter is a band-stop filter that achieves a deep cutoff of >OD6 within a 20-30 nm bandwidth around 633 nm, reflecting/absorbing laser light in this band to <0.0001%, while maintaining >90% high transmission for other wavelengths. It utilizes an ultraviolet fused silica substrate with multilayer dielectric coatings on the surface, featuring a thickness of only 2.5-5 mm, a clear aperture of ?21 mm, a wavefront error of <λ/2 (@633 nm), 60-40 scratch-dig surface quality, and a center wavelength tolerance of ±2 nm. It is primarily used in laser Raman spectrometers, fluorescence detection, biomedical imaging, and laser safety protection, effectively blocking interference from helium-neon lasers or other 633 nm lasers while ensuring high transmission of background signals, thereby improving signal-to-noise ratio and measurement accuracy.