High Speed Liquid Crystal Variable Retarder

Meadowlark’s newest liquid crystal (LC) product, the high speed LC variable retarder (HS LCVR) has a 10X speed improvement over our award winning standard LCVR. The sub-millisecond speeds are achieved without the 50/50 duty cycle drive scheme required by our ferroelectric liquid crystal components, but are nearly as fast. The new LCVR uses nematic liquid crystal materials to electrically control polarization and provide tunable retardation by changing the effective birefringence of the material with applied voltage, thus altering the input polarized light to any chosen elliptical, linear or circular polarization.

Our precision HS LCVR requires unique fabrication and assembly steps. We construct these retarders using optically flat fused silica windows coated with our transparent conductive Indium Tin Oxide (ITO). Our ITO coating is specially designed for maximum transmission from 400 – 700 nm.
Response Time

Liquid Crystal Variable Retarder response time depends on several parameters, including layer thickness, viscosity, temperature, variations in drive voltage and surface treatment. Liquid crystal response time is proportional to the square of the layer thickness and therefore, the square of the total retardance.

SPECIFICATIONS

• Retarder Material: Nematic liquid crystal
• Substrate Material: Optical quality synthetic fused silica
• Wavelength Range 450 –700 nm
• Typical LC Rise Time (10 –90%): 50 µs @ 532 nm 
• Typical LC Fall Time (90 –10%): 500 µs @ 532 nm
• Retardance: 0 to λ/2
• Transmitted Wavefront Distortion(at 632.8 nm): ≤λ/4
• Surface Quality: 40 –20 scratch-dig
• Beam Deviation: ≤2 arc min
• Reflectance (per surface): ≤0.5% at normal incidence
• Operating Temperature (Internally Heated): 50°C
• Recommended Safe Operating Limit: 500 W/cm2, CW 300 mJ/cm2, 10 ns, visible