Femtosecond laser micromachining of Si-on-SiO/sub 2/ for photonic crystal fabrication

Summary form only given. We report promising progress toward the direct fabrication of photonic crystal structures utilizing femtosecond laser machining. Our preliminary results demonstrate the capability of femtosecond laser pulses with a near IR wavelength of 775 nm to drill sub-0.5 /spl mu/m holes in Si-on-SiO/sub 2/. More important, it is shown that the spacing (750 nm) can be less than wavelength. The required spacing for 1D waveguide photonic crystal is /spl sim/400 nm. Therefore, our current investigation is focused on reducing the hole spacing. We also need to measure beam pointing stability and pulse-to-pulse energy fluctuation of the laser in order to see how they affect hole diameter and positioning accuracy, respectively.