Embedded anisotropic microreflectors by femtosecond-laser nanomachining

Directly written embedded structures created within fused silica by a femtosecond Ti:sapphire laser are observed to strongly reflect blue light. Reflection emerges only in a direction parallel to the polarization axis of the writing laser. This anisotropic-effect is caused by a periodic modulation of refractive index of amplitude Deltansimilar to10(-2) with a characteristic period Lambdasimilar to150 nm over a spot size similar to1.5 mum. We show that the origin of the anisotropic reflection is the primary cause of other anisotropic phenomena reported in recent experiments. (C) 2002 American Institute of Physics.