Tredicucci, Alessandro

Date: Tuesday, July 5, 2016
Time: 10:30
Place: ETH Zurich, Hönggerberg, HPF G 6
Host: Jérôme Faist

Perspectives in THz optomechanics

Alessandro Tredicucci
Università di Pisa and NEST, Pisa, Italy

The interaction between radiation and mechanical motion at the microscale or even nanoscale is now being heavily investigated. Known as cavity optomechanics, this field has produced extraordinary advances in fabrication and characterization of nanomechanical objects with impressive results towards the achievement of quantum effects in mesoscopic systems. Applications are to be found in quantum communication, ultrasensitive measurements of displacements and forces, and fundamental studies of quantum physics.
So far, this interaction has relied on the detuning between a passive optical resonator and an external pump laser. In such setups, light can induce forces on a mechanical resonator directly through radiation pressure or indirectly through photothermal forces, which result from thermal expansion of the structure under light-induced heating. Recently, however, systems in which the mechanical element is integrated within a laser cavity itself are being proposed. This new field of so-called "active optomechanics" is rapidly progressing, offering new exciting possibilities, thanks to the large number of photons available and the mechanical feedback action on the laser properties themselves. It is also a concept particularly suited to the THz regime, where wavelength-size mechanical oscillators can more easily be integrated within the microresonators of quantum cascade devices.
In a different direction, mechanical deformation of nanostructured materials like graphene, has been predicted to deeply affect in a tailorable way the electronic structure of such systems, so much that the new term "strain engineering" has been coined to describe this rapidly expanding field. This approach could form the basis for a new class of THz devices in which mechanical control of the photonic response is achieved.
This talk will discuss ideas, concepts and perspectives for THz optomechanics, focusing on a few selected systems of technological relevance.