Microprinting of fluorescent dye droplets by optical vortex laser induced forward transfer

We demonstrate the laser induced forward transfer of fluorescent dye solution thin films with different viscosity by employing a single 532-nm nanosecond optical vortex pulse. Upon irradiating the laser pulse, a single microdroplet is ejected from the donor film, and it is deposited onto a receiver substrate. Well-aligned microdots with the same diameter were printed on the substrate with optical vortex, whereas the production of microdots in uniform size was prevented with a conventional Gaussian beam. In addition, we demonstrate the microprinting of a number of droplets by optical vortex.