Optical guided-mode resonance filter

A method of producing a tuneable output wave, comprising the steps of:

• providing a planar, rotatable diffraction grating having a plurality of variable parameters including:
• thickness, a plurality of equi-distant periodic structures placed within said grating, and permittivity typical of dielectric materials in the visible and infrared spectral regions;
• directing an input wave possessing a characteristic wavelength spectrum upon a surface of said grating at an angle of incidence which varies depending upon a position of said rotatable diffraction grating;
• changing at least one said parameter for producing a tuneable output wave and redirecting said input wave incident upon said grating to produce said tuneable output wave in accordance with said changing step.

A method of producing a narrowband tuneable laser, comprising the steps of:

• providing at least one partially transmissive concave mirror;
• providing a planar diffraction grating spaced apart from and facing the concave portion of said mirror, said grating having a plurality of variable parameters including thickness, spacing between a plurality of equi-distant structures within said grating, and a permittivity typical of dielectric materials in the visible and infrared spectral regions;
• providing an optical laser medium between said concave mirror and said grating;
• directing an input broadband optical wave from said laser medium upon said grating surface;
• backward diffracting said input broadband optical wave from said grating as an output narrowband optical wave in accordance with changing at least one said variable parameter;
• repeating said steps of directing and backward diffracting to continuously produce a tuned said output narrowband optical backward diffracted wave between said grating and said mirror;
• and
• transmitting a portion of said output narrowband optical wave through said partially transmissive concave mirror as output from said narrowband tuneable laser.