Processing of chalcogenide glass by the femtosecond laser pulses for achieving highly non-linear photonic structures

The direct modification of materials by femtosecond (fs) laser pulses enables fabrication of 3D compact photonic devices, which are potentially cheap and allow for dense integration. In the writing of well-defined structures by such means non-linear processes are essential. Multi-photon absorption is an effect that initiates plasma formation in illuminated region and subsequent variation of its optical properties. Due to the non-linear character of absorption, sub-wavelength-scale (in particular, nano-scale) structures can be fabricated.