Liquid Crystal Polarization Grating (LCPG) Technology

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.