Liquid crystal waveplate #4567

Overview
Meadowlark Optics Liquid Crystal Variable Retarders provide precise electrical control of polarization by changing effective birefringence with applied voltage. Increasing voltage reduces retardance. These units are intended for active polarization control in metrology and medical instrumentation, including stress analysis, pharmaceutical ingredient analysis, and biological microscopy.

Key Features

• Precise electrical control of polarization
• Multiple wavelength options from UV to NIR
• Compatible with Meadowlark Optics liquid crystal controllers (analog and digital)

Construction and Optical Description
Retarders consist of a birefringent nematic liquid crystal layer sandwiched between optically flat fused silica windows. The windows are coated with transparent conductive indium tin oxide (ITO) to maximize transmission across the specified wavelength range. Each unit is supplied with measured retardance versus voltage performance data for its specified wavelength range.

Electrical Drive and Operation
These variable retarders must be driven with an AC waveform containing no DC component to prevent ionic buildup and potential damage to the liquid crystal layer. A 2 kHz square wave of adjustable amplitude is the recommended control waveform. Meadowlark Optics liquid crystal controllers meet these drive requirements.

Applications
Typical applications: polarization control for metrology, medical instrumentation, stress/strain analysis, pharmaceutical analysis, and biological microscopy. Uncompensated units exhibit a residual retardance of approximately 30 nm at high voltage.

Included / Mechanical
Each retarder is supplied with measured retardance vs voltage performance data and a coaxial cable with mating connector for connection to a compatible controller.

Technical specifications

• Optical element: Birefringent nematic liquid crystal layer
• Windows: Optically flat fused silica
• Window coating: Transparent conductive Indium Tin Oxide (ITO)
• Wavelength options: Multiple configurations spanning UV to NIR
• Residual (uncompensated) retardance: ~30 nm at high voltage
• Drive requirements: AC waveform with no DC component; recommended 2 kHz square wave with adjustable amplitude
• Supplied data: Retardance vs voltage performance data per specified wavelength range
• Accessories supplied: Coaxial cable with mating connector
• Recommended controller compatibility: Meadowlark Optics liquid crystal controllers (analog and digital)