Optical microelectromechanical devices have found many applications as light splitters, modulators, and tunable gratings. Most such applications have relied on micromachined hard materials, which are capable of fast response but only over a limited mechanical range. Aschwanden and Stemmer show that soft materials such as electroactive polymers, or artificial muscles, can be used to extend that mechanical response because of the enormous strains (∼380%) they can sustain when a voltage is applied. The authors pattern their elastomeric polymer with an initial grating period of 1 μm and append carbon black electrodes using contact printing. By sweeping the bias across these electrodes up to 4.5 kV, they can continuously vary the grating period over a range of up to 32% (to a 1.3-μm period). This change is sufficient to tune the transmission wavelength across the optical spectrum from blue to red, suggesting the possibility of display technology applications if the driving voltage can be diminished. — ISO
Opt. Lett. 31, 2610 (2006).