ABSTRACT
Ultrafast lasers have revolutionized material processing, opening a wealth of new applications in many areas of science. A recent technology that allows the cleaving of transparent materials via non-ablative processes is based on focusing and translating a high-intensity laser beam within a material to induce a well-defined internal stress plane. This then enables material separation without debris generation. Here, we use a non-diffracting beam engineered to have a transverse elliptical spatial profile to generate high-aspect-ratio elliptical channels in glass of a dimension 350 nm×710 nm and subsequent cleaved surface uniformity at the sub-micron level.
ABSTRACT
Hydrogenated amorphous silicon (a:Si-H) has recently been recognized as a highly nonlinear CMOS compatible photonic platform. We experimentally demonstrate the generation of a supercontinuum (SC) spanning over 500 nm in a-Si:H photonic wire waveguide at telecommunication wavelengths using femtosecond input pulse with energy lower than 5 pJ. Numerical modeling of pulse propagation in the waveguide, based on the experimentally characterized dispersion profile, shows that the supercontinuum is the result of soliton fission and dispersive wave generation. It is demonstrated that the SC is highly coherent and that the waveguides do not suffer from material degradation under femtosecond pulse illumination. Finally, a direct comparison of SC generation in c-Si and a-Si:H waveguides confirms the higher performances of a-Si:H over c-Si for broadband low power SC generation at telecommunication wavelengths.
