Waveplate Retardance Metrology: The Basics and Beyond
Summary Waveplates are essential optical components for controlling and measuring polarization states of light. They modify polarization through a parameter called retardance, without affecting the degree of polarization. The most commonly required retardances are half-wave and quarter-wave, and their accuracy directly impacts the purity of the output polarization state. However, both waveplate manufacturers and users […]
Australian Lidar Measurements of Aerosol Layers Associated with the 2015 Calbuco Eruption
Summary The Calbuco volcano eruption in southern Chile (April 22–23, 2015) injected volcanic aerosols into the atmosphere, forming distinct stratospheric aerosol layers observed over South Australia and Tasmania. Using lidar measurements, atmospheric trajectory modeling, and satellite data (CALIOP & OMPS), researchers confirmed that these layers originated from Calbuco. Key findings include: Stratospheric aerosol layers detected […]
Twisted Nematic Liquid Crystal Devices
Summary Meadowlark Optics has been a leader in nematic liquid crystal (LC) devices for over 25 years, pioneering liquid crystal variable retarders (LCVRs) for precision optical applications. LCVRs offer low-voltage electrical control of retardance (typically ≤20V) and have largely replaced high-voltage Pockels cells in many applications. However, Twisted Nematic (TN) Liquid Crystal Devices provide distinct […]
Scientific and Industrial Liquid Crystal Polarimetry Applications
Summary Because the human eye is insensitive to polarization, valuable optical information often goes unnoticed. However, polarimetry—the measurement of a light wave’s polarization state—is crucial in fields such as biology, chemistry, astronomy, and remote sensing. This paper explores methods for accurately determining the retardance value and fast axis position of an unknown waveplate and highlights […]
Liquid Crystal in Precision Optical Devices
Summary While liquid crystal technology is widely known for display applications, its role in scientific and engineering fields is rapidly expanding. Liquid crystal devices (LCDs) are now critical for beam steering, wavefront modulation, and polarization switching in precision optical systems. Unlike traditional flat-panel displays, high-performance liquid crystal optics require specialized construction techniques to achieve superior […]
Achromatic Ferroelectric Liquid Crystal Polarization Rotator
Summary Precise polarization rotation with minimal polarization purity loss is essential for optical switching, polarimetry, and microscopy. Traditional liquid crystal (LC) polarization rotators enable non-mechanical tuning, but their performance is limited to specific wavelengths. Ferroelectric liquid crystal (FLC) devices, however, offer faster response times and can switch between two orthogonal polarization states. By placing an […]
An Economical Means for Accurate Azimuthal Alignment of Polarization Optics
Summary Accurate azimuthal alignment of polarization optics, such as polarizers and retarders, is crucial for many polarized light applications. This document introduces a simple opto-mechanical tool designed for precise alignment using two rotatable mounts—one holding a polarizer and the other a half-wave retarder. The method of swings, illustrated with the Poincaré Sphere, is employed to […]
New Optics for Astronomical Polarimetry
Summary New optical technologies are revolutionizing astronomical polarimetry by expanding the range of polarization optics for telescopes and scientific imaging. Liquid crystal retarders, including nematic liquid crystals and ferroelectric liquid crystals, offer electrical control of polarization with low voltage and fast response times, making them ideal for adaptive optics and infrared imaging. Polymer retarders provide […]
