Microfluidic Fiber Lasers

Microfluidic dye lasers (MDL) have recently emerged as promising candidates to facilitate the fusion of optics and fluidics at the microscale. Their primary advantage over gas or solid state lasers is the inherent wavelength tunabililty which can be achieved by changing the type of dye used, the dye concentration, or the host solution. Here, we report on the design and characterization of a MDL with a fundamentally new characteristic, one that couples the fluid mechanics property of the gain medium with its optical properties, namely, surface tension enabled laser cavity tunability. This laser cavity is composed of a liquid dye-doped plug positioned inside a hollow core photonic bandgap fiber, with its surface contours and surrounding cylindrical solid cladding defining the cavity geometry. With this geometry, we demonstrate two unique laser features: 1) linear motion of a lasing source that emits light radially from a fiber and 2) modulation of the laser threshold by fluid mechanical deformation of the laser cavity.