Liquid Crystal Polarization Grating Application Note
Meadowlark Optics Download the LCPG App Note Liquid Crystal Polarization
Key Features
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:
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.
CPG 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
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 |
We also offer a commercial product line consisting of unmounted LCPGs without integrated anti-reflection (AR) coatings so that we can provide customers with the best price. Please contact our knowledgeable Solutions Engineers regarding custom options, including custom diffraction angles, aperture sizes, and wavelengths through the visible to midwave infrared.
Fundamentals
Liquid crystal polarization gratings (PGs) are fascinating optical components that differ from traditional diffraction gratings, like ruled, Bragg, or holographic gratings. In particular, PGs exhibit polarization sensitivity, can have diffraction efficiency approaching 100%, and are much less sensitive to incident angle than, for example, Bragg or volume holographic gratings. To understand how this is possible, it is important to first understand how PGs work.
These plots show typical zero-order leakage spectra for different LCPG specifications. The LCPG diffraction efficiency is highest where the zero-order leakage is at a minimum.
Meadowlark Optics Download the LCPG App Note Liquid Crystal Polarization
Download PDF Fundamentals Liquid crystal polarization gratings (PGs) are fascinating
Geometric-phase microscopy (GPM) uses changes in the phase of light