  Flexible and tensile wavelength-tunable micrometer-sized random lasers in the
form of microporous polymer fiber are demonstrated. The fibers are fabricated
by directly drawing from an aqueous mixture and subsequently selective chemical
etching in a green solvent. Size-dependent lasing threshold and spectrum are
investigated. Owing to mechanical flexibility, wavelength-tuning of 5.5 nm is
achieved by stretching the fiber.
