Electrically modulated radiation filters

Claim 2

A structure for electrically modulating the intensity of a monochromatic beam of radiation, said structure comprising i. an optical resonator for said radiation consisting of a transparent layer between two parallel boundaries: ii. at least one of said boundaries comprising a thin first solid layer sandwiched between a second solid layer and said resonator, said first solid layer having a lower refractive index than said second layer and than said resonator, said first and second layers transparent to said radiation; iii. said beam incident through said second layer on said first layer at an angle sufficiently close to the grazing angle that said incident beam will undergo total reflection from said first layer; said first layer sufficiently thin that a portion of said incident beam tunnels through said first layer into said resonator; said portion propagating along said resonator and undergoing multiple reflections at said boundaries; part of said propagating portion extracted across one of two said boundaries, said part contributing to an out-going beam by interference; iv. means to generate an electric field substantially perpendicular to said first layer, said electric field varying the refractive index of at least one of said resonator, said first layer and said second layer thereby affecting the intensity of said outgoing beam.

Claim 3

The structure of claim 1, whereby said second solid layer is silicon, said first solid layer is a thin film on said silicon selected from the group of materials consisting of SiO2 and Si3N4, said means of applying said electric field comprising said layer of silicon as one electrode, and a second electrode spaced from said layer of silicon by at least said thin film selected from said group of materials.

Claim 4

The structure of claim 1, whereby said means to generate an electric field comprises two electrodes applied at said structure.

Claim 5

The structure of claim 3, whereby a potential applied at said electrodes generates an electric field of orientation substantially perpendicular to said two boundaries.

Claim 6

The structure of claim 4, whereby at least one of said two electrodes is a thin transparent metal film substantially parallel to one of said two boundaries.

Claim 7

The structure of claim 4, whereby one of said two electrodes is a semiconducting layer.

Claim 8

The structure of claim 6, whereby said semiconducting layer is adjacent to one of saiD boundaries.

Claim 9

The structure of claim 4, whereby both electrodes are semiconducting layers.

Claim 10

The structure of claim 8, whereby one of said semiconducting layers is adjacent to one of said boundaries, and the other semiconducting layer is adjacent to the other said boundary.

Claim 11

A structure for electrically modulating the intensity of a monochromatic beam of radiation, said structure comprising i. an optical resonator for said radiation consisting of a transparent layer between two parallel boundaries; ii. one of said two boundaries comprising a thin second layer and the other of said two boundaries comprising a thin third layer, said second layer sandwiched between said resonator and a fourth layer; said third layer sandwiched between said resonator and a fifth layer, said second layer having a lower refractive index than said resonator and said fourth layer, layer; and said third layer having a lower refractive index than said resonator and said fifth layer; said second, third, fourth and fifth layers transparent to said radiation; iii. said beam incident through said fourth layer on said second layer at an angle larger than the critical angle of total reflection so that total reflection occurs at said second layer, said second layer sufficiently thin so that portions of said beam from said fourth layer penetrate through said second layer into said resonator, where said portions propagate undergoing multiple total reflections on said second and third layers, part of said radiation in said resonator penetrating through at least one of said second and fourth layers contributing to an outgoing beam by interference; iv. means to generate an electric field substantially perpendicular to said second and third layers, said electric field varying the refractive index of at least one of said resonator, second, third, fourth and fifth layers thereby affecting the intensity of said outgoing beam.

Claim 12

A structure for electrically modulating the intensity of a monochromatic beam of radiation, said structure comprising i. an optical resonator for said radiation consisting of a transparent layer between two parallel boundaries; ii. one of said two boundaries comprising a thin second layer and the other of said two boundaries comprising a thin third layer, said second layer sandwiched between said resonator and a fourth layer; said third layer sandwiched between said resonator and a fifth layer, said second layer having a lower refractive index than said resonator and said fourth layer, layer; and said third layer having a lower refractive index than said resonator and said fifth layer; said second, third, fourth and fifth layers transparent to said radiation; iii. said beam incident through said fourth layer on said second layer at an angle larger than the critical angle of total reflection so that total reflection occurs at said second layer, said second layer sufficiently thin so that portions of said beam from said fourth layer penetrate through said second layer into said resonator, where said portions propagate undergoing multiple total reflections on said second and third layers, part of said radiation in said resonator penetrating through at least one of said second and fourth layers contributing to an outgoing beam by interference; iv. means to generate an electric field substantially perpendicular to said second and third layers, said electric field varying the refractive index of at least one of said resonator, second, third, fourth and fifth layers thereby affecting the intensity of said outgoing beam.

Claim 13

The structure of claim 10 comprising a silicon slab as one of said fourth or fifth layers, said silicon slab serving as an electrode, and a thin film of SiO2 or Si3N4 as one of said second or third layers.