Lab Chip 13, 2675–2678 (2013)

An all-biological laser whose active medium, resonator, pump and substrate are fabricated entirely from biological materials would be a very useful tool. Such a laser would in principle be biocompatible and biodegradable, so that it could be used in applications such as toxicity sensors for food or used in vivo to overcome the limited penetration of light through biological tissue. Now, Christoph Vannahme and colleagues from Denmark and Germany have demonstrated a single-mode distributed feedback laser made from gelatine doped with riboflavin (vitamin B2); both materials are nontoxic and digestible. The laser resonator was formed from a corrugated single-mode, second-order distributed feedback laser slab on a nanoimprinted low-index polymer. The researchers obtained lasing at wavelengths of 543 nm and 562 nm, which agreed well with modelling results. Although these lasers used biologically active materials, they had non-biological substrates; it is hoped that in the future, biological substrates can be used to realize the goal of an all-biological laser.