Generation of optical Schrodinger cat states in intense laser-matter interactions

The physics of intense laser-matter interactions(1,2) is described by treating the light pulses classically, anticipating no need to access optical measurements beyond the classical limit. However, the quantum nature of the electromagnetic fields is always present(3). Here we demonstrate that intense laser-atom interactions may lead to the generation of highly non-classical light states. This was achieved by using the process of high-harmonic generation in atoms(4,5) in which the photons of a driving laser pulse of infrared frequency are upconverted into photons of higher frequencies in the extreme ultraviolet spectral range. The quantum state of the fundamental mode after the interaction, when conditioned on the high-harmonic generation, is a so-called Schrodinger cat state, which corresponds to a superposition of two distinct coherent states: the initial state of the laser and the coherent state reduced in amplitude that results from the interaction with atoms. The results open the path for investigations towards the control of the non-classical states, exploiting conditioning approaches on physical processes relevant to high-harmonic generation.

Automated summary

The study shows that intense laser-atom interactions can generate highly non-classical light states by using high-harmonic generation in atoms, leading to the production of Schrodinger cat states. Controlling these non-classical states may be achieved through exploring physical processes relevant to high-harmonic generation.