Three-dimensional Holographic Recording by Femtosecond Pulses

We demonstrate fabrication of two-dimensional (2D) photonic crystal (PhC) structure inside the volume of SU-8 resist film by four beams interference. This structure, actually, is a 3D structure fabricated inside the film without sample scanning or laser beam steering. The mechanism of recording ill transparent, dielectrics is discussed in terms of third harmonic generation, white light continuum, and thermal emission by 'hot' electrons.