Bianco Federica, Miseikis Vaidotas, Convertino Domenica, Xu Ji-Hua, Castellano Fabrizio, Beere Harvey E, Ritchie David A, Vitiello Miriam S, Tredicucci Alessandro, Coletti Camilla
Opt Express. 2015 May 4;23(9):11632-40. doi: 10.1364/OE.23.011632.
We investigated the room-temperature Terahertz (THz) response as saturable absorber of turbostratic multilayer graphene grown on the carbon-face of silicon carbide. By employing an open-aperture z-scan method and a 2.9 THz quantum cascade laser as source, a 10% enhancement of transparency is observed. The saturation intensity is several W/cm2, mostly attributed to the Pauli blocking effect in the intrinsic graphene layers. A visible increase of the modulation depth as a function of the number of graphene sheets was recorded as consequence of the low nonsaturable losses. The latter in turn revealed that crystalline disorder is the main limitation to larger modulations, demonstrating that the THz nonlinear absorption properties of turbostratic graphene can be engineered via a proper control of the crystalline disorder and the layers number.
我们研究了生长在碳化硅碳面上的涡轮层状多层石墨烯作为饱和吸收体的室温太赫兹（THz）响应。通过采用开孔z扫描方法并以2.9太赫兹量子级联激光器作为光源，观察到透明度提高了10%。饱和强度为几瓦每平方厘米，这主要归因于本征石墨烯层中的泡利阻塞效应。由于低非饱和损耗，记录到调制深度随石墨烯片层数的增加而明显增加。后者进而表明晶体无序是更大调制的主要限制，这表明通过适当控制晶体无序和层数，可以调控涡轮层状石墨烯的太赫兹非线性吸收特性。
