  Developing thermal analogues of field-effect transistor could open the door
to a low-power and even zero-power communication technology working with heat
rather than electricity. These solid-sate devices could also find many
applications in the field of active thermal management in numerous technologies
(microelectronic, building science, energy harvesting,conversion,...). Recent
theoretical works has suggested that a photonic transistor made with three
terminals can in principle be used to switch, modulate, and even amplify heat
flux through exchange of thermal photons. Here, we report an experimental
demonstration of thermal transistor effect using a non-contact system composed
by a temperature-controlled metal-insulator-based material interacting in
far-field regime with two blackbodies held at two different temperatures. We
demonstrate that, with a tiny change in the temperature of the active layer,
the heat flux received by the cold blackbody can be drastically modified. An
amplification parameter of heat flux over 20 is reported.
