Liquid Crystal Polarization Grating (LCPG) Technology

Key Features

  • Low size, weight, and power
  • Random-access scanning
  • Robust non-mechanical operation
  • Large apertures possible (>15cm)
  • Diffraction-limited wavefront quality
  • High diffraction efficiency (>99%)
  • Up to 80°×80° steering demonstrated
  • Demonstrated in VIS to MWIR

Liquid Crystal Polarization Grating Operating Principles

Non-mechanically reconfigurable optics with vastly superior size, weight, and power requirements compared to their mechanical counterparts
The use of LCPGs in nonmechanical beam steering is a novel technique, and Meadowlark has the patent on this approach (US 8,982,313 B2).

Performance Graphs

Meadowlark Optics’ Liquid Crystal Polarization Gratings utilize spatially varying birefringence to create highly efficient polarization-sensitive gratings. Circularly polarized light can be directed into either the +1 or -1 order depending on the handedness of the incident light. By using a stack of N LCPGs and half-waveplate switches, it is possible to steer to 2N discrete angles in 1-D or 2-D arrays.

Liquid crystal polarization gratings are also known as geometric phase gratings, Pancharatnam-Berry phase gratings, and diffractive waveplates. These transmissive gratings efficiently (> 99.5%) diffract circularly polarized light to either the first positive or negative order, based on the handedness of the incident light. By incorporating fast electro-optic half-wave polarization retarders to control the handedness of polarization, Meadowlark can develop custom LCPG devices and systems with a range of leading capabilities:

  • Wide-angle beam steering > 100°
  • Large apertures > 20 cm
  • Sub-millisecond switching times
  • Dramatically reduced size, weight, and power (SWaP) requirements
  • Random-access and inertia-less beam steering

Dynamic focusing is also available.

 

Non-Mechanical Steering for a Range of Aperture Sizes

 

Meadowlark can build LCPGs and LC switches using thin 200 μm glass and with apertures ranging from 2 mm to 200 mm. Thin glass enables discrete steering to >1,000 revolvable angles with transmissive assemblies < 1 cm thick. Meanwhile the ability to steer large beams over large angles makes this approach unique among non-mechanical steering technologies for replacing large gimbals or steering large collection apertures in optical receiver paths.

 

LCPG Steering for Lidar

 

LCPG technology excels at non-mechanical beam steering for many narrowband sensors including lidar. To date, we have demonstrated LCPG beam steering for both coherent and direct detection lidars and both monostatic and bistatic architectures. Due to the ability to steer light in discrete steps over large angles, LCPG beam steering is particularly well suited to steering flash lidar systems and coherent doppler lidar wind sensing systems.

ORDERING INFORMATION
Meadowlark can provide custom systems to meet your needs using the patented liquid crystal polarization grating (LCPG) beam steering technology. When contacting us for a quote, please provide:•Clear Aperture (mm)
•Operating Wavelength (nm)
•1D or 2D Steering
•Number of Angles
•Maximum Steering Angle (°)
•Response Time/Switching Speed (ms)
•Housing/Mechanical Interface Requirements
•Description of Application & Additional Details

Liquid Crystal Suite

Variable Retarders

 Liquid Crystal Variable Retarder

UV Variable Retarder

MWIR Variable Retarder

OEM LCVR

Rotators

Achromatic High-Speed Rotator

Binary Rotator

Polarization Rotator

 

Shutters / Attenuators

Achromatic High-Speed Shutter

High Contrast Shutter

Variable Attenuator

 

Controllers

Analog Controller

FLC Controller

LC Digital Interface Controller

Temperature Controller

Frequently asked Questions

Most of the commercial interest in Liquid Crystal Polarization Gratings has been for non-mechanical beam steering and so that is the current focus of this document. Please inquire directly regarding LCPG tunable lens assemblies and individual LCPG and LCP lens components.

request a custom quote or get technical answers

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