Ultra-Sharp Angular Filtering of Far-Field Signals With Graded-Index Multilayers

Dielectric multilayers with graded index treat the propagating waves impinging at different angles very differently, due to the occurred total internal reflection. Such an ultra-sharp change in the response can be exploited for filtering, manipulation, and tailoring of spatially distributed electromagnetic signals. Various utilities of the proposed filter such as power splitting, spatial dc isolation, beam shifting, and low-profile energy interaction are demonstrated. The regarded setup can be vital as component in the operation of integrated photonic devices dealing with optical signal processing and analog information control.