Time-reversed lasing based on one-dimensional gratings

We show that a one-dimensional grating can generally exhibit time-reversed lasing better than a uniform slab. As the effective refractive index of a grating can be controlled by adjusting the geometric parameters, the time-reversed lasing can be realized for any incident wavelength in it. Moreover, the operating frequency range of coherently perfect absorption for a grating structure is remarkably broad compared with a uniform structure. All these behaviors are demonstrated with GaAs/Air gratings illuminated around 794.8 nm. The properties of the proposed grating imply the potential applications such as detectors, transducers, and broad band absorber.