Graphene doped by lithium atoms supports a strong Dirac plasmon, a weak acoustic plasmon and a strong interband plasmon Li(π + σ). Here we demonstrate that applying a positive or negative bias on the lithium-doped graphene causes the appearance (‘switching ON’) or disappearance (‘switching OFF’) of the Li(π + σ) plasmon and the ‘conversion’ of the Dirac plasmon into a strong acoustic plasmon. This has two important consequences: 1. bias-controlled UV optical activity of the Li-doped graphene and 2. bias-controlled position of the 2D plasmon centroid. These effects turn out to be very robust and independent of the details of the experimental setup, which means that they should be easily experimentally verified, and very attractive for potential applications.

锂原子掺杂的石墨烯具有较强的狄拉克等离子体激元，较弱的声学等离子体激元和较强的带间等离子体激元Li（π  +  σ）。在此我们证明，在掺杂锂的石墨烯上施加正偏压或负偏压会导致Li（π  +  σ）的出现（“打开”）或消失（“关闭”）。）等离子体激元和狄拉克等离子体激元“转换”为强声等离子体激元。这具有两个重要的结果：1.掺杂Li的石墨烯的偏光控制UV光学活性和2.二维等离激元质心的偏光控制位置。这些效果非常强大，并且与实验设置的细节无关，这意味着它们应该易于进行实验验证，并且对于潜在的应用非常有吸引力。