We demonstrate a first simultaneous measurement of the real and imaginary parts of the refractive index of a highly turbid medium by observing the real-time reflectance profile of a divergent laser beam made incident on the surface of the turbid medium. We find that the reflectance data are well described by Fresnel theory that correctly includes the effect on total internal reflection of angle-dependent penetration into the turbid medium.

Peiponen et al. [Opt. Lett.35, 4108 (2010)] have expressed concern that a theoretical model we proposed in Calhoun et al. [Opt. Lett.35, 1224 (2010)] for total internal reflection from a turbid medium may be inconsistent with the experimental data, in the sense that the model fails to take into account unexplained oscillations in our data. We show that their concern arises from misinterpretation of our data and theory, and is, therefore, unfounded. NOTE: Optics Letters apologizes to the authors for the delay in the publication of this Reply.

A frequency-tunable half-wavelength dipole antenna is realized using an array of electrically actuated liquid-metal pixels. The liquid-metal pixelated dipole antenna demonstrates frequency reconfigurability by switching between resonances at 2.51 GHz, 2.12 GHz, 1.85 GHz, and 1.68 GHz.

Liquid metal is actuated against the force of gravity using low-voltage, low-power continuous electrowetting. The liquid metal moves from a lower reservoir to an upper reservoir, a distance of 12 mm, in 1.66 s. This demonstrates that the electrokinetic actuation of liquid metal is not limited to two-dimensional movement.

A new method is presented for actuating liquid metals, based on the physical deformation of ferrofluid in response to an applied magnetic field. Using this ferrofluidic actuation, a liquid-metal slug was moved through a channel at an average velocity of 15.6 mm/s. The hydrocarbon-based ferrofluid exhibits negligible loss from 50 MHz to 20 GHz, and can thus serve as an alternative carrier fluid to hydrochloric acid or sodium hydroxide for liquid-metal-based reconfigurable radio-frequency circuits.