Photostability of the laser emission from dye-doped spherical particles

Micrometer-sized spherical particles containing laser dyes such as Rhodamine 6G, DCM and Pyridine I have been fabricated by the vibrating orifice technique for the spherical cavity micro-laser. A cylindrical liquid jet of diluted hybrid raw materials passing through an orifice breaks up into equal-sized droplets by mechanical vibration. Then the solvent of these droplets was evaporated during flying with carrier gas and subsequently solidified into dye-doped hybrid-microspheres in ammonium water trap. The microspheres of different dye contents were pumped by second harmonic pulses of Q-switched Nd: YAG laser (532 nm wavelength, repetition rate is 10 Hz) and their photodegradation of lasing intensities were measured against shot number of pumping pulses. Degree of the degradation strongly depended on the pumping power and the dye content incorporated in the microsphere. Suitable pumping power and dye content gave the best data for the photostability: Laser out-put energy was consumed 50% of the initial value after 100,000 pulses for R6G and Pyridine 1, and 240,000 pulses for DCM.