Cut-off Wavelength (Shortpass Filter)

Shortpass filter:

• Cut-off wavelength: This represents the longest wavelength that the filter transmits efficiently. Beyond this wavelength, the filter rapidly blocks light with increasing effectiveness. Typically defined as the wavelength where the transmission drops to 50% of its peak value.

• Shortpass filters essentially "pass short wavelengths" and block longer ones. So, the cut-off wavelength defines the upper limit of the transmitted wavelengths.