Microfluidic tunable photonic band-gap device

We introduce a method for tuning a photonic band-gap material by means of displacing microfluidic plugs. The fluid is introduced into air voids that constitute the structure of the photonic crystal and is displaced using a capillary heater. The photonic crystal geometry is obtained using a microstructured optical fiber, comprising a periodically spaced array of air holes that is interrogated in the transverse direction, creating a “tall microchip.” Optical spectra are compared to band structure calculations of an idealized band-gap material.