Use CWL 488nm with 5–10nm FWHM for 488nm argon-ion laser line cleanup, source isolation, or detector-side laser signal selection.
488nm is a well-known argon-ion laser line. For laser-line filtering, the key specs are CWL match near 488nm, FWHM such as 5nm or 10nm, transmission at 488nm, and OD blocking across the unwanted wavelength range.
488nm fluorescence excitation
Use CWL 488nm or 490nm with 10–30nm FWHM for GFP/FITC/Alexa Fluor 488-type fluorescence excitation channels.
For fluorescence microscopy, flow cytometry, and confocal imaging, the 488nm filter is usually placed on the excitation side before the sample. The goal is to deliver the blue excitation band while reducing source leakage and crosstalk into the emission path. The emission filter should be centered around the actual green emission band, not at 488nm.
Cyan-blue LED or broadband visible source
Use CWL 485–490nm with 20–50nm FWHM for cyan-blue LED cleanup or practical blue-green band selection from broadband visible sources.
For LED or lamp-based systems, the source spectrum is broader than a laser line. Use 20–30nm FWHM for more defined excitation or illumination control, or 50nm FWHM when higher transmitted signal is more important.