Space-variant subwavelength polarization grating and applications thereof

A method of modulating an intensity of laterally uniform, polarized light of at most a certain maximum wavelength, comprising the steps of:

• (a) solving an equation
• ∇×{right arrow over (K)}(K0,β)=0
• for a grating vector {right arrow over (K)} that is defined by a wavenumber K0 and by a direction β relative to a reference direction, the modulation depending on β, {right arrow over (K)} being such that at least a portion of a grating fabricated in accordance with {right arrow over (K)} has a local period less than the maximum wavelength of the light;
• (b) fabricating said grating in accordance with said grating vector {right arrow over (K)};
• and
• (c) directing the light at said grating.

A method of imposing a polarization state having a predetermined, laterally varying azimuthal angle ψ on light of at most a certain maximum wavelength, comprising the steps of:

• (a) solving an equation
• ∇×{right arrow over (K)}(K0,β)=0
• for a grating vector {right arrow over (K)} that is defined by a wavenumber K0 and by a direction β relative to a reference direction, β being related to ψ by β=ψ−Δψ(K0), {right arrow over (K)} being such that at least a portion of a grating fabricated in accordance with {right arrow over (K)} has a local period less than the maximum wavelength of the light;
• (b) fabricating said grating in accordance with {right arrow over (K)};
• and
• (c) directing the light at said grating.

A method of measuring a polarization state of light of at most a certain maximum wavelength, comprising the steps of:

• (a) providing a grating having a transmission axis that varies in one lateral dimension, at least a portion of said grating having a local period less than the maximum wavelength of the light;
• (b) directing the light at said grating;
• (c) measuring an intensity of the light that has traversed said grating;
• and
• (d) determining three Stokes parameters of the light from said intensity.

A method of measuring a polarization state of light of at most a certain maximum wavelength, comprising the steps of:

• (a) providing a grating having a reflection axis that varies in one lateral dimension, at least a portion of said grating having a local period less than the maximum wavelength of the light;
• (b) directing the light at said grating;
• (c) measuring an intensity of the light that is reflected from said grating;
• and
• (d) determining three Stokes parameters of the light from said intensity.

A method of transforming an incident beam of laterally uniform, polarized light into a transformed beam having a modulated intensity, comprising the steps of:

• (a) solving an equation
• ∇×{right arrow over (K)}(K0,β)=0
• for a grating vector {right arrow over (K)} that is defined by a wavenumber K0 and by a direction β relative to a reference direction, the modulation depending on β, {right arrow over (K)} being such that the transformed beam is substantially free of propagating orders higher than zero order;
• (b) fabricating said grating in accordance with said grating vector {right arrow over (K)};
• and
• (c) directing the incident beam at said grating.

A method of transforming an incident light beam into a transformed beam upon which is imposed a polarization state having a predetermined, laterally varying azimuthal angle ψ, comprising the steps of:

• (a) solving an equation
• ∇×{right arrow over (K)}(K0,β)=0
• for a grating vector {right arrow over (K)} that is defined by a wavenumber K0 and by a direction β relative to a reference direction, β being related to ψ by β=ψ−Δψ(K0), {right arrow over (K)} being such that the transformed beam is substantially free of propagating orders higher than zero order;
• (b) fabricating said grating in accordance with {right arrow over (K)};
• and
• (c) directing the incident beam at said grating.

A method of measuring a polarization state of an incident light beam, comprising the steps of:

• (a) providing a grating having a transmission axis that varies in one lateral dimension, said grating being operative to transform the incident beam into a transformed beam that is substantially free of propagating orders higher than zero order;
• (b) directing the incident beam at said grating;
• (c) measuring an intensity of the transformed beam;
• and
• (d) determining three Stokes parameters of the light from said intensity.