Liquid-based infrared optical switch

We report an infrared (IR) optical switch using a position-shifting glycerol droplet. The droplet is surrounded by density-matched oil. In the voltage-on state, the droplet shifts in one direction. Upon removing the voltage, the droplet returns to its original position with the aid of interfacial tensions. Due to the strong absorption of glycerol at 1.55 mu m, our IR optical switch shows similar to 95:1 contrast ratio and similar to 200 ms response time. Such a device is promising for fiber optical switch and various IR optical attenuators

Reconfigurable fabrication of scattering-free polymer network liquid crystal prism/grating/lens

We report a simple reconfigurable printing method for fabricating submillisecond-response and scattering-free polymer network liquid crystal photonic devices, such as prism, grating, and lens. To suppress light scattering in the visible region, we reduce the domain sizes by controlling polymer concentration, selecting a high viscosity liquid crystal (LC) host, and performing UV curing at a low temperature. To demonstrate the configurability, we printed a LC micro-prism array with similar to 300-mu m feature size and a circular lens with 1.3-mm radius without any pre-patterned templates. This reconfigurable printing technique enables fast design iterations and should have widespread applications for fabricating display and photonic devices

A novel adaptive mechanical-wetting lens for visible and near infrared imaging

We demonstrate an adaptive mechanical-wetting lens with a concentric reservoir to reduce image aberrations and overcome the gravity effect. This lens adopts liquid pressure to change the interface between two immiscible liquids which, in turn, changes the focal length of the resultant liquid lens. Good optical performance, high resolution, and a wide dynamic range of both positive and negative optical power are achieved. Since no PDMS is employed, such lenses can extend their working range to infrared region by choosing proper liquids

Polarization independent VOA based on dielectrically stretched liquid crystal droplet

A polarization independent variable optical attenuator (VOA) based on a dielectrically stretched liquid crystal (LC) droplet is demonstrated. In the voltage-off state, the proposed VOA has the smallest attenuation. As voltage increases, the LC droplet is stretched by a dielectrophoretic force, which gradually deflects the beam leading to an increased attenuation. Such a VOA can cover the entire C-Band. At lambda = 1550 nm, the following results are obtained: dynamic range similar to 32 dB, insertion loss similar to 0.7 dB, polarization dependent loss similar to 0.3 dB, and response time similar to 20 ms