Electro-optical diffractive waveplate beam shaping system

• US 10,423,045 B2
• Filed: 11/14/2016
• Issued: 09/24/2019
• Est. Priority Date: 11/14/2016
• Status: Active Grant

• Current Assignee: Beam Engineering For Advanced Measurements Co.
• Original Assignee: Beam Engineering For Advanced Measurements Co.
• Inventors: Roberts, David E., Tabirian, Nelson V.
• Primary Examiner(s): Kim, Richard H
• Application Number:
  US15/350,856
• Publication Number:
  US 20180136535A1
• Time in Patent Office: 1,044 Days
• Field of Search: None
• CPC Class Codes: G02B 27/0012 Optical design, e.g. procedures, algorithms, optimisation routines
• CPC Class Codes: G02B 27/0916 Adapting the beam shape of a semiconductor light source such as a laser diode or an LED, e.g. for efficiently coupling into optical fibers coupling into light guides using intermediate optical elements G02B6/4204; details of lighting devices in general F21V; semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission H01L33/00
• CPC Class Codes: G02B 27/0927 Systems for changing the beam intensity distribution, e.g. Gaussian to top-hat
• CPC Class Codes: G02B 27/0944 Diffractive optical elements, e.g. gratings, holograms gratings per se G02B5/18; holograms used as optical elements per se G02B5/32
• CPC Class Codes: G02B 27/4261 having a diffractive element with major polarization dependent properties
• CPC Class Codes: G02B 5/0236 the diffusion taking place within the volume of the element
• CPC Class Codes: G02B 5/0268 characterized by the fabrication or manufacturing method
• CPC Class Codes: G02B 5/0278 used in transmission
• CPC Class Codes: G02B 5/3016 involving passive liquid crystal elements optical properties of liquid crystals G02F1/0063; polarising elements associated with active liquid crystal devices G02F1/133528
• CPC Class Codes: G02F 1/29 for the control of the position or the direction of light beams, i.e. deflection
• CPC Class Codes: G02F 2201/305 diffraction grating
• CPC Class Codes: G02F 2203/01 transmissive
• CPC Class Codes: G02F 2203/22 diffractive

Abstract

Optical beam shaping systems and methods can include an illumination source and a diffractive waveplate diffuser. The diffractive waveplate diffuser includes a layer of patterned optically anisotropic material. In one embodiment, the layer of patterned optically anisotropic material is fabricated in the form of patterned, optically anisotropic liquid crystal polymer. In another embodiment, the layer of patterned optically anisotropic material is a layer of liquid crystal, the diffractive waveplate diffuser also includes two alignment layers and two transparent conductive coatings, and the properties of the liquid crystal layer are controlled by the application of an electric potential between the two transparent conductive coatings. A method is provided for designing the alignment pattern of the layer of optically anisotropic material.

Claims

1. An optical beam shaping system comprising:

(a) at least one illumination source; and

(b) at least one diffractive waveplate diffuser, each diffuser comprising a layer of optically anisotropic material wherein the orientation of anisotropy axis is spatially patterned in a predetermined manner; and

wherein optical retardance introduced by said layer of optically anisotropic material is one-half wave at an operating wavelength; and

wherein the phase of said illumination source propagated through the film is shaped to produce a selected diffraction pattern in a target plane when illuminated with said illumination source; and

wherein shaping of an optical phase is obtained by a local angle of anisotropy axis in a predetermined orientation pattern of the layer of said optically anisotropic material with respect to a reference direction.

2. The system according to claim 1, wherein the optically anisotropic material with patterned orientation of anisotropy axis comprises:

at least one layer of a liquid crystal polymer.

3. The system according to claim 1, wherein the illumination source comprises:

(a) at least one laser, and

(b) collimating optics.

4. The system according to claim 1, wherein the illumination source comprises:

(a) at least one light emitting diode; and

(b) collimating optics.

5. The system according to claim 1, wherein at least one of the diffractive waveplate diffusers further comprises:

(a) transparent conductive coatings on two boundaries of the patterned layer of optically anisotropic material;

(b) an electronic control system for applying an electric field across the patterned layer of optically anisotropic material;

(c) the patterned layer of optically anisotropic material with the optical retardance is switched between one-half wave and zero at an operating wavelength when said electric field is applied.

6. The system according to claim 5, wherein the patterned layer of optically an isotropic material consists of a liquid crystal, bounded on each side by an alignment layer.

7. The system according to claim 5 comprising at least two diffractive waveplate diffusers with different beam shaping properties.