



01662nas a2200217   4500008004100000245004300041210004300084260001500127300001100142490000600153520108300159100001601242700001501258700001601273700001901289700001101308700002101319700001901340700001801359856006701377       2016                        eng d00aDouble Quantum Dot Floquet Gain Medium0 aDouble Quantum Dot Floquet Gain Medium  c2016/11/07  a0410270 v63 a<p><span style="color: rgb(0, 0, 0); font-family: &quot;Lucida Grande&quot;, helvetica, arial, verdana, sans-serif; font-size: 14.4px;">Strongly driving a two-level quantum system with light leads to a ladder of Floquet states separated by the photon energy. Nanoscale quantum devices allow the interplay of confined electrons, phonons, and photons to be studied under strong driving conditions. Here we show that a single electron in a periodically driven DQD functions as a &quot;Floquet gain medium,&quot; where population imbalances in the DQD Floquet quasi-energy levels lead to an intricate pattern of gain and loss features in the cavity response. We further measure a large intra-cavity photon number n_c in the absence of a cavity drive field, due to equilibration in the Floquet picture. Our device operates in the absence of a dc current -- one and the same electron is repeatedly driven to the excited state to generate population inversion. These results pave the way to future studies of non-classical light and thermalization of driven quantum systems.</span></p>1 aStehlik, J.1 aLiu, Y.-Y.1 aEichler, C.1 aHartke, T., R.1 aMi, X.1 aGullans, Michael1 aTaylor, J., M.1 aPetta, J., R.  uhttp://journals.aps.org/prx/abstract/10.1103/PhysRevX.6.041027