Abstract

Refractive index changes on the order of unity are exploited in vanadium dioxide (VO₂) to control the phase of optical beams over distances of less than 100 nm. While VO₂ undergoes a phase transition from insulator to metal, the optical phase of beams at 800 nm (in transmission) and at 1310 nm (in reflection) are modulated while keeping all other properties of light intact, including field amplitude and polarization. The refractive index changes yield Δk = 10⁷ rad/m, much higher than that of typical electro-optic materials. The results suggest potential applications for nano-sized flat lenses and phase devices.

© 2014 Optical Society of America