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The investigation of Nonlinear properties at the nanoscale is a growing field of research of great importance from both fundamental and applicative point of view. Concerning the fundamental one, there have been a number of investigations both experimental and theoretical, but the question is still “open”, while from an applicative point of view, there are some important prospective, for example to realize nanophotonics devices with improved performances.

Among numerous nonlinear optics phenomena, stimulated Raman scattering (SRS) is one of the most interesting, due to its significant recent implications in nanophotonics and biophotonics. Being the essence of SRS phenomena a ‘light amplification’, one of the  most important application is the realization of amplifiers or laser sources in bulk materials, in fiber and in integrated optics format as well.

The creation of silicon light emitters and lasers has often been considered as the holy grail of silicon photonics because of its potential payoff as well as the significant challenge posed by nature. The Raman approach to silicon photonics has been successful since its inception. It has produced the first silicon lasers and optical amplifier

The ability to construct nano-objects and nanodevices is expected to lead to the development of fully functional nanodevices. Tailoring nonlinear optical properties of nanomaterials is especially relevant for the design of efficient light. A giant Raman gain was already obtained by our team from Si-nc in silica, up to four orders of magnitude higher than that from crystalline silicon. We note that the basic idea behind the invention of silicon Raman laser was that the SRS effect in silicon was about 104 times larger than that in the glass fiber; therefore, an active device with typical dimensions of a few centimeters instead of several kilometres was realized. Analogously, according to our results, a Raman laser with a length of a few microns can be developed based on Si-nc. This achievement would lead to all the advantages of combining optical and electronic functions on a single chip.

The basic aim of this activity is to investigate Raman gain and other third order nonlinear properties in some different materials considered “post-silicon”, taking advantage of nonlinear and ultrafast optical spectroscopy.

 

Contact: Luigi Sirleto

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