Optical system with a dielectric subwavelength structure having high reflectivity and polarization selectivity

A system for transferring a beam of electromagnetic radiation having a vacuum wavelength, said system comprising:

• a first dielectric medium with a first refractive index n1 wherein said beam can propagate;
• a second dielectric medium with a second refractive index n2;
• and
• a dielectric region in between said first and said second medium, characterized in that said region is a grating having a periodicity of the dielectric properties parallel to said region, said periodicity having a period that is smaller than the wavelength of the electromagnetic radiation in said second dielectric medium, said dielectric properties and said periodicity of said dielectric region further being chosen such that the average refractive index of said dielectric region is not greater than said first refractive index n1 and not less than said second refractive index n2 and that the dielectric region establishes that said beam when incident on said dielectric region is reflected for essentially 100% into the specular zero-order reflection, said dielectric region further characterized in that said region has a sufficiently large variation of said dielectric properties within one repetition of said period such that said beam when incident on said dielectric region excites at least two modes propagating within said dielectric region along a direction normal thereto, wherein the arrangement thereof is such that the angle of incidence of the incident beam is substantially normal to the grating and further characterized in that the grating parameters are chosen so that the reflection and transmission behavior of said system provides minimized zero order transmission in conjunction with maximized zero order reflection and wherein said grating parameters are generated by the following expressions Λ λ = 2 n 1 2 - 1 n 0 , eff = n 1 2 - ( λ Λ ) 2 d λ = 3 2 ⁢ ( 2 ⁢ n 0 , eff - 1 ) f = 50 ⁢ ⁢ %
• wherein
• n0,eff=effective index of a first propagating mode in the grating region,
• λ=vacuum wavelength,
• Λ=grating periodicity,
• f=a grating filling factor,
• d=grating depth.

A system for transferring a beam of electromagnetic radiation having a vacuum wavelength, said system consisting essentially of:

• a first dielectric medium with a first refractive index no wherein said beam can only propagate in said first dielectric medium;
• a second dielectric medium with a second refractive index n2;
• and
• a dielectric region in between said first and said second medium, characterized in that said region has a periodicity of the dielectric properties parallel to said region, said periodicity having a period that is smaller than the wavelength of the electromagnetic radiation in said second dielectric medium, said dielectric properties and said periodicity of said dielectric region further being chosen such that the average refractive index of said dielectric region is not greater than said first refractive index n1 and not less than said second refractive index n2 and that their refractive index values cooperatively establish that said beam when incident on said dielectric region is reflected more than 90% into the specular zero-order reflection.

A system for transferring a beam of electromagnetic radiation having a vacuum wavelength, said system consisting essentially of:

• a first dielectric medium with a first refractive index n1 wherein said beam can propagate;
• a second dielectric medium with a second refractive index n2;
• and
• a dielectric region in between said first and said second medium, characterized in that said region has a periodicity of the dielectric properties parallel to said region, said periodicity having a period that is smaller than the wavelength of the electromagnetic radiation in said second dielectric medium, said dielectric properties and said periodicity of said dielectric region further being chosen such that the average refractive index of said dielectric region is not greater than said first refractive index n1 and not less than said second refractive index n2 and that their refractive index values cooperatively establish that said beam when perpendicularly incident to said dielectric region is reflected more than 90% into the specular zero-order reflection, wherein said dielectric region has a sufficiently large variation of said dielectric properties within one repetition of said period such that said beam when incident on said dielectric region excites at least two higher order modes propagating within said dielectric region along and incident path.