Hybrid semiconductor polymer resonant grating waveguide structures

When illuminated with an incident beam of light, grating waveguide structures (GWS), of specific geometrical and optical parameters, have a resonant behavior. Under such behavior, an incident beam, which is normally completely transmitted, is wholly reflected at a certain wavelength, with a very narrow resonance spectral bandwidth. Thus, such structures can serve as very narrow spectral filters for a variety of applications. After reviewing the basic principles, we present polymer-based grating waveguide structures which were fabricated using spin-coating techniques and holographic recording of gratings. Experimental results yielded narrow bandwidth optical filtering, with 55% reflection efficiencies and 1 nm bandwidth at FWHM. Also, we present our latest theoretical and experimental developments of semiconductor and polymer-based grating waveguide structures. The results reveal that for semiconductor-based grating waveguide structures the resonance spectral bandwidth can be as low as 0.1 nm, and the contrast ratio as high as 1000, with finesses greater than 10 000. Such structures were placed inside a laser cavity and served as a back mirror to determine lasing wavelength. (C) 2001 Elsevier Science B.V. All rights reserved.