2010/08/31 by Stefano Longhi · 1 citation
Physics and Astronomy · #quant-ph
paper · pdf · doi:10.1103/physreva.82.031801
published as Phys. Rev. A 82, 031801(R) (2010) · 5 pages; to be published in Phys. Rev. A (Rapid Communications)
arxiv created 2010/08/31 · arxiv updated 2015/05/19
In a recent work, Y.D. Chong et al. [Phys. Rev. Lett. \bf 105, 053901 (2010)] proposed the idea of a coherent perfect absorber (CPA) as the time-reversed counterpart of a laser, in which a purely incoming radiation pattern is completely absorbed by a lossy medium. The optical medium that realizes CPA is obtained by reversing the gain with absorption, and thus it generally differs from the lasing medium. Here it is shown that a laser with an optical medium that satisfies the parity-time (PT) symmetry condition ε(-r)=ε^*(r) for the dielectric constant behaves simultaneously as a laser oscillator (i.e. it can emit outgoing coherent waves) and as a CPA (i.e. it can fully absorb incoming coherent waves with appropriate amplitudes and phases). Such a device can be thus referred to as a PT-symmetric CPA-laser. The general amplification/absorption features of the PT CPA-laser below lasing threshold driven by two fields are determined.