US 6,678,297 B2 · Chiral laser utilizing a quarter wave plate

Abstract

The inventive chiral laser achieves lasing by placing an electro-luminescent emitting layer with quarter wave plate properties and a layer of cholesteric liquid crystal (CLC) between two electrodes. The electrode connected to the emitting layer is highly reflective and serves as a source of electrons, while the second electrode, connected to the hole-transporting CLC, serves as a source of holes. The recombination of electrons and holes in the emitting layer produces luminescence. If a right handed CLC structure is used, then right circularly polarized emission is reflected from the CLC as right circularly polarized light, and then converted to linear polarized light by passing through quarter wave plate emitting layer. It is then reflected by the electrode and converted again into the right circularly polarized light in a second pass through the quarter wave plate emitting layer. The emitted and reflected light emissions are incrementally amplified on each pass through the emitting layer and thus a laser cavity is formed. Once a predefined lasing threshold is reached, lasing occurs perpendicular to the CLC layer. Because the laser cavity is formed only for right circularly polarized light, polarized laser emission will occur.

Claims35

Dependent claims

A chiral laser apparatus comprising:

a layered structure comprising:
a chiral layer of a predetermined handedness having a top portion and a bottom portion;
a quarter wave plate active material layer of a thickness L having a top and a bottom portion, configured to emit electromagnetic radiation when subjected to excitation and disposed above said chiral layer, wherein said active material layer bottom portion is in substantial contact with said chiral layer top portion, and wherein said active material layer is operable to:
(i) convert circularly polarized electromagnetic radiation passing therethrough to linearly polarized electromagnetic radiation, and
(ii) convert linearly polarized electromagnetic radiation passing therethrough is to circularly polarized electromagnetic radiation;
a reflector having a top and a bottom portion, configured to reflect said electromagnetic radiation, coming from said top portion of said active material layer, wherein said reflector bottom portion is in substantial contact with said active material layer top portion;
and
excitation means for applying excitation to said layered structure to produce polarized lasing directed through said chiral layer in a direction away from said active material layer.

5 more elements

A chiral laser apparatus comprising:

a layered structure comprising:
a chiral layer of a predetermined handedness having a top portion and a bottom portion and configured as a hole-transporting medium;
a quarter wave plate electro-luminescent layer of thickness L, a top portion and a bottom portion, and disposed above said chiral layer, wherein said electro-luminescent layer bottom portion is in substantial contact with said chiral layer top portion, and wherein said electro-luminescent layer is operable to:
(i) convert circularly polarized electromagnetic radiation passing therethrough to linearly polarized electromagnetic radiation, and
(ii) convert Linearly polarized electromagnetic radiation passing therethrough is to circularly polarized electromagnetic radiation;
a first electrode, disposed above said electro-luminescent layer, having electron source properties and a highly reflective bottom portion in substantial contact with said electro-luminescent layer top portion;
a second electrode, disposed below said chiral layer and in substantial contact with said chiral layer bottom portion, having hole source properties;
and
excitation means, connected to said first and second electrodes, for applying excitation to said layered structure such that electron and hole recombination occurs in said electro-luminescent layer to produce polarized lasing directed through said second electrode.

6 more elements

A method of lasing in a chiral laser, comprising the steps of:

(a) providing a layered structure comprising;
a chiral layer of a predetermined handedness having a top portion and a bottom portion;
a quarter wave plate active material layer of a thickness L having and a top and bottom portion, configured to emit electromagnetic radiation when subjected to excitation and disposed above said chiral layer, wherein said active material layer bottom portion is in substantial contact with said chiral layer top portion, and wherein said active material layer is operable to:
(i) convert circularly polarized electromagnetic radiation passing therethrough to linearly polarized electromagnetic radiation, and (ii) convert linearly polarized electromagnetic radiation passing therethrough is to circularly polarized electromagnetic radiation;
a reflector having a top and a bottom portion, configured to reflect said electromagnetic radiation, coming from said top portion of said active material layer, wherein said reflector bottom portion is in substantial contact with said active material layer top portion;
and
(b) applying excitation to said layered structure to produce polarized lasing directed through said chiral layer in a direction away from said active material layer.

4 more elements

Dependencies are inferred from the claim text.

Chiral laser utilizing a quarter wave plate

Life of this patent

Chiral laser utilizing a quarter wave plate

Life of this patent

Abstract

Claims35