Space-variant subwavelength dielectric grating and applications thereof
First Claim
1. An optical device, for manipulating incident light of at most a certain maximum wavelength, comprising a substantially planar grating formed in a dielectric material and having a space-variant, continuous grating vector, at least a portion of said grating having a local period less than the maximum wavelength of the incident light.
1 Assignment
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Accused Products
Abstract
An optical device includes a planar subwavelength grating (10) formed in a dielectric material and having a laterally varying, continuous grating vector. When used to modulate a beam of laterally uniform polarized electromagnetic radiation incident thereon, the device passes the incident beam with a predetermined, laterally varying transmissivity and/or retardation. When used to effect polarization state transformation, the device transforms a beam of electromagnetic radiation incident thereon into a transmitted beam having a predetermined, laterally varying polarization state. The device (214) can be used to provide radially polarized electromagnetic radiation for accelerating subatomic particles or for cutting a workpiece. The device (108) also can be used, in conjuction with a mechanism for measuring the lateral variation of the intensity of the transmitted beam, for measuring all four Stokes parameters that define the polarization state of the incident beam.
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Citations
69 Claims
- 1. An optical device, for manipulating incident light of at most a certain maximum wavelength, comprising a substantially planar grating formed in a dielectric material and having a space-variant, continuous grating vector, at least a portion of said grating having a local period less than the maximum wavelength of the incident light.
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36. A method of modulating laterally uniform, polarized light of at most a certain maximum wavelength, comprising the steps of:
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(a) solving an equation ∇
×
{overscore (K)}(K0,β
)=0
for a grating vector {overscore (K)} that is defined by a wavenumber K0 and by a direction β
relative to a reference direction, the modulation depending on β
, {overscore (K)} being such that at least a portion of a grating fabricated in accordance with {overscore (K)} has a local period less than the maximum wavelength of the light;
(b) fabricating said grating in a dielectric material in accordance with said grating vector {overscore (K)}; and
(c) directing the light at said grating. - View Dependent Claims (37, 38)
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39. A method of imposing a laterally varying polarization state on light of at most a certain maximum wavelength, comprising the steps of:
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(a) solving an equation ∇
×
{overscore (K)}(K0,β
)=0
for a grating vector {overscore (K)} that is defined by a wavenumber K0 and by a direction β
relative to a reference direction, the laterally varying polarization state being at least partially defined by β
, {overscore (K)} being such that at least a portion of a grating fabricated in accordance with {overscore (K)} has a local period less than the maximum wavelength of the light;
(b) fabricating said grating in a dielectric material in accordance with {overscore (K)}; and
(c) directing the light at said grating. - View Dependent Claims (40, 41, 42)
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43. A method of measuring a polarization state of light of at most a certain maximum wavelength, comprising the steps of:
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(a) providing a substantially planar grating having a transmission axis that varies in one lateral direction 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 all four Stokes parameters of the light from said intensity. - View Dependent Claims (44, 45, 46, 47, 48)
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49. A method of measuring a polarization state of light of at most a certain maximum wavelength, comprising the steps of:
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(a) providing a substantially planar grating having a reflection axis that varies in one lateral direction 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 all four Stokes parameters of the light from said intensity.
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- 50. An optical device, for transforming an incident beam of light into a transformed beam of light, comprising a substantially planar grating formed in a dielectric material and having a space-variant continuous grating vector, such that the transformed beam is substantially free of propagating orders higher than zero order.
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64. A method of transforming an incident beam of laterally uniform, polarized light into a modulated transmitted beam, comprising the steps of:
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(a) solving an equation ∇
×
{overscore (K)}(K0,β
)=0
for a grating vector {overscore (K)} that is defined by a wavenumber K0 and by a direction β
relative to a reference direction, the modulation depending on β
, {overscore (K)} being such that the transmitted beam is substantially free of propagating orders higher than zero order;
(b) fabricating said grating in a dielectric material in accordance with said grating vector {overscore (K)}; and
(c) directing the light at said grating. - View Dependent Claims (65)
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66. A method of transforming an incident light beam into a transmitted beam upon which is imposed a laterally varying polarization state, comprising the steps of:
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(a) solving an equation ∇
×
{overscore (K)}(K0,β
)=0
for a grating vector {overscore (K)} that is defined by a wavenumber K0 and by a direction β
relative to a reference direction, the laterally varying polarization state being at least partially defined by β
, {overscore (K)} being such that the transmitted beam is substantially free of propagating orders higher than zero order;
(b) fabricating said grating in a dielectric material in accordance with {overscore (K)}; and
(c) directing the light at said grating. - View Dependent Claims (67)
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68. A method of measuring a polarization state of an incident light beam, comprising the steps of:
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(a) providing a substantially planar grating having a transmission axis that varies in one lateral direction, said grating being operative to transform the incident beam into a transmitted beam that is substantially free of propagating orders higher than zero order;
(b) directing the light at said grating;
(c) measuring an intensity of the transmitted beam; and
(d) determining all four Stokes parameters of the light from said intensity.
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69. A method of measuring a polarization state of an incident light beam, comprising the steps of:
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(a) providing a substantially planar grating having a reflection axis that varies in one lateral direction, said grating being operative to transform the incident beam into a reflected beam that is substantially free of propagating orders higher than zero order;
(b) directing the light at said grating;
(c) measuring an intensity of the reflected beam; and
(d) determining all four Stokes parameters of the light from said intensity.
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Specification