Rugate filters, explained by RP Photonics Encyclopedia; gradient-index filters, multiple notch filter, fabrication, optical properties, analysis, design, optimization
14NOF - Precision Type Reflective Notch Filters
632.8-16 NNF Iridian Narrow Notch Filter for Raman
Design and development of an optical reflective notch filter using the ion assisted deposition technique with stepwise modulated thickness for avionics applications
Notch Filter (Bandstop): What is it? (Circuit & Design) | Electrical4U