A nanoimprinted, optically tuneable organic laser

We present a means to optically tune the emission of an organic laser reversibly over a range of 14nm. This is enabled by incorporating a photochromic spiropyran (10,30-dihydro-10,30,30-trimethyl-6-nitrospiro[2H-1-benzopyran-2,20-(2H)-indole]) into the gain medium formed by the laser dye Rhodamine 700 in poly(methyl methacrylate). This is structured by nanoimprinting to form a distributed feedback resonator. Exposure of the device to ultraviolet and visible light leads to a reversible refractive index change of the photochromic additive and the gain medium, which enables the continuous shift of the laser wavelength. This is possible without compromising the optical gain properties of the device.