Application of a microchip laser pumped photonic crystal fiber supercontinuum source for high sensitive cavity ring down optical loss measurements

Precise optical loss measurements are a prerequisite for the development of new optical materials and complex optical multilayers. A flat supercontinuum (400 nm - 1650 nm), generated by a photonic crystal fiber pumped with a train of kHz nanosecond Q-switched microchip laser pulses at 1064 nm is used for high sensitive cavity ring down (CRD) loss measurements. The supercontinuum based CRD-technique enables the precise determination of the reflectivity of high-reflective coatings from R = 0.995 to R = 0.99995 or of the transmission loss of optical materials from tau = 0.005 to tau = 0.00005 with an accuracy better than 2 . 10(-6), and covers an extreme wide spectral range of more than 1000 nm.