The Liquid Crystal Variable Attenuator (LCVA) from Meadowlark Optics provides continuous control of light intensity in real time. Our attenuator consists of an LC Variable Retarder (with attached compensator) operating between crossed linear polarizers. With crossed polarizers, light transmission is maximized by applying the correct voltage to achieve the half-wave retardation of the LC cell. In half-wave operation, the direction of the incoming polarization is rotated by 90° so that the light passes through the second polarizer. Minimum transmission is achieved when the retarder operates with zero (or a whole number of) waves.
The transmission decreases with increasing amplitude of the applied AC voltage (half-wave to zero-wave retardation). The relationship between the transmittance T and the retardation degree (in degrees) for a crossed polarizer configuration is given by: T(Θ) = 1/2 [1 – cos(Θ)] Tmax, where Tmax is the maximum transmittance when the retardation is exactly one half-wave (or 180°).
Our variable optics stand for precision and reliability. If you have any further questions about the systems, please feel free to send us a non-binding inquiry. Further information about the products and all technical data sheets for each variant can be found here: meadowlark.com.
