A new concept for noninvasive optical sensing: random lasing

Optical sensing has been subject to a great interest for the moderate intrusiveness of its operation. The introduction of random lasers in ’90s has opened the door for developing a new kind of optical sensors. In such a source, disorder is introduced within an inverted medium, increasing the lifetime of the radiation without the presence of an optical cavity. The striking point is that the spectral characteristics of the output emission are strongly dependent on the scattering properties of the medium, suggesting new methods to investigate disordered materials. Recently, a novel concept for optical sensing based on the physics of random laser has been reported, overcoming the limits due to the alteration of the investigated sample by injecting an active material. Here we present a characterization of such a kind of sensor, suggesting non-invasive and also in-vivo applications.