CYCLOIDAL DIFFRACTIVE WAVEPLATE AND METHOD OF MANUFACTURE

• US 20140211145A1
• Filed: 01/28/2014
• Published: 07/31/2014
• Est. Priority Date: 01/28/2013
• Status: Active Grant

• Current Assignee: Beam Engineering For Advanced Measurements Co.
• Original Assignee: United States Secretary of the Army
• Inventors: Tabirian, Nelson V., Nersisyan, Sarik R., Kimball, Brian R., Steeves, Diane M.
• Granted Patent: US 9,658,512 B2
• Time in Patent Office: Days
• US Class Current: 349/201
• CPC Class Codes: G02F 1/134363 for applying an electric field parallel to the substrate, i.e. in-plane switching [IPS]
• CPC Class Codes: G02F 1/292 by controlled diffraction or phased-array beam steering controlled diffraction for optical switching G02F1/31
• CPC Class Codes: Y10T 29/49155 Manufacturing circuit on or in base

Abstract

A cycloidal diffractive waveplate (50) comprising first and second substrate layers (52, 54),

a liquid crystal layer (60C, 60H) provided between the first and second substrate layers, and transparent positive electrodes (56) and transparent negative electrodes (58) provided on the first substrate layer. The liquid crystal layer has a diffractive state (60C) in which the optical axes of the liquid crystal molecules are periodically rotated across a plane of the waveplate and a non-diffractive state (60H) in which the optical axes of the liquid crystal molecules are all orientated in the same direction in the plane of the waveplate. The electrodes (56, 58) are arranged in an alternating series, such that when an electric voltage is applied to the electrodes an electric field is produced in the plane of the waveplate and the liquid crystal layer is switched from the diffractive state to the non-diffractive state. A method of manufacturing the cycloidal diffractive waveplate is also provided.

Claims

1. A method of fabricating a cycloidal diffractive waveplate, the method comprising:

forming a first substrate layer;

forming a plurality of transparent positive electrodes and a plurality of transparent negative electrodes on the first substrate layer, the electrodes being arranged in an alternating series;

forming a second substrate layer; and

forming a liquid crystal layer between the first substrate layer and the second substrate layer, the liquid crystal layer being formed of liquid crystal molecules each having an optical axis and the liquid crystal layer being formed with a periodic molecular structure, and wherein the liquid crystal layer has a diffractive state in which the optical axes of the liquid crystal molecules are periodically rotated across a plane of the waveplate and a non-diffractive state in which the optical axes of the liquid crystal molecules are orientated in the same direction in the plane of the waveplate.

2. The method of claim 1, wherein the plurality of transparent positive electrodes and the plurality of transparent negative electrodes are formed by forming a layer of a transparent conductive material on the first substrate layer and etching an electrode pattern into the layer of a transparent conductive material.

3. The method of claim 1, wherein transparent positive electrodes and transparent negative electrodes are formed by direct deposition of a transparent conductive material onto the first substrate layer.

4. The method of claim 1, wherein the electrodes are arranged in the alternating series across the first substrate layer in a first direction and the liquid crystal layer has a modulation axis which is orientated in a second direction, substantially perpendicular to the first direction, within a plane of the diffractive waveplate.

5. A cycloidal diffractive waveplate comprising:

a first substrate layer;

a second substrate layer;

a liquid crystal layer provided between the first substrate layer and the second substrate layer, the liquid crystal layer formed of liquid crystal molecules each having an optical axis and the liquid crystal layer having a periodic molecular structure, and wherein the liquid crystal layer has a diffractive state in which the optical axes of the liquid crystal molecules are rotated across a plane of the waveplate and a non-diffractive state in which the optical axes of the liquid crystal molecules are orientated in the same direction in the plane of the waveplate; and

a plurality of transparent positive electrodes and a plurality of transparent negative electrodes, the electrodes provided on the first substrate layer and the electrodes arranged in an alternating series, such that when an electric voltage is applied to the electrodes an electric field is produced in the plane of the waveplate and the liquid crystal layer is switched from the diffractive state to the non-diffractive state.

6. The cycloidal diffractive waveplate of claim 5, wherein the electrodes comprise a transparent conductive material provided on the first substrate layer and etched to form the alternating series of positive and negative electrodes.

7. The cycloidal diffractive waveplate of claim 5, wherein said electrodes comprise a transparent conductive material directly deposited on the first substrate layer to form electrodes.

8. The cycloidal diffractive waveplate of claim 5, wherein the electrodes are arranged in the alternating series across the first substrate layer in a first direction and the liquid crystal layer has a modulation axis which is orientated in a second direction, substantially perpendicular to the first direction, within a plane of the waveplate.