Liquid Combination with High Refractive Index Contrast and Fast Scanning Speeds for Electrowetting Adaptive Optics

Electrowetting adaptive optical devices are versatile, with applications ranging from microscopy to remote sensing. The choice of liquids in these devices governs its tuning range, temporal response, and wavelength of operation. We characterized a liquid system, consisting of 1-phenyl-1-cyclohexene and deionized water, using both lens and prism devices. The liquids have a large contact angle tuning range, from 173 to 60°. Measured maximum scanning angle was realized at ±13.7° in a two-electrode prism, with simulation predictions of ±18.2°. The liquid's switching time to reach 90° contact angle from rest, in a 4 mm diameter device, was measured at 100 ms. Steady-state scanning with a two-electrode prism showed linear and consistent scan angles of ±4.8° for a 20 V differential between the two electrodes, whereas beam scanning using the liquid system achieved ±1.74° at 500 Hz for a voltage differential of 80 V.