Quasi-Optical Notch Filters For Plasma Imaging Applications

Quasi-optical notch filters are employed to protect plasma imaging arrays from stray radiation from high power electron cyclotron resonance heating (ECRH) sources. A new imaging arrangement permits stacking of multiple filters to maximize ECRH rejection. Simulations indicate that a stack of three filters can provide a notch depth of > 60 dB at 140 GHz, and retain this high rejection over an incident angle range of +/- 80 degrees.