Investigation of micro laser drilling on thin glass fibers by femtosecond laser

High-precision processing and microfabrication has been realized with the use of a femtosecond laser which with an ultrahigh-peak power and an ultrashort pulse. Such processing of glass materials has never been accomplished through conventional methods, and has been realized only through nonlinear optical phenomena using femtosecond lasers. -Moreover, photonic devices such as optical waveguides, photonic crystals and 3D-memory devices have been developed. In our laboratory, precise holes with high aspect ratios are created in micro-scale glass materials for the purpose of developing novel optical devices. This research is conducted by using a fundamental wave (800 nm) and a second harmonic generation (SHG: 400 nm) of a Ti-Sapphire laser with various irradiation conditions at each wavelength in order to find the optimal processing parameters. In addition, optical silica fibers have been used target objects. First, a calibration experiment was carried out by fixing the repetition frequency and the number of pulses and changing the irradiation fluence. Next, another calibration experiment was carried out by fixing the irradiation frequency and the number of pulses and changing the repetition frequency. Last, an experiment on changing the number of pulses was conducted by using the fundamental wave. In this paper, the results of these experiments and the processing parameters required for the development of novel optical devices are described.