Study of higher optical nonlinearities in atoms near multiphoton resonances

G. Grynberg, Bernard Cagnac, F. Biraben

HU Jie-sheng

This paper reveals that spontaneous-emission-mediated emissive multiphoton progress can efficiently enhance nonlinear-optical signal in the cascade system:1) under the same parameters,the strongest nonlinear-optical signal takes place in the cascade system nearly double than it in the Λ system at coherent-population-trapping;2)within a certain range,the pump-atoms detuning controlled in the cascade system,we can get an increase in the generated nonlinear-optical signal efficiently,which is relaxed restrictions on the resonance between pump fields and atoms,and it is easy to operate.

F. S. Cataliotti, R. Scheunemann, Theodor W. Hänsch +1 more

We have investigated higher order multiphoton Raman resonances with two pulsed optical frequencies. Multiphoton transfer with up to 50 photons is observed with milliwatts of laser power. We demonstrate that the spectral width of the multiphoton resonances can be far below the Fourier transform linewidth of the driving optical pulses. The functional dependence of the transition linewidth on the number of exchanged photons is found to vary with the pulse shape. Our experiment is performed with laser-cooled rubidium atoms confined in a CO2-laser optical dipole trap.

С. А. Бахрамов

S. P. Zhao, Matthias G. Krauss, Tom Bienaimé +4 more

In optical and solid-state architectures, low-order nonlinearities are commonly exploited for quantum state preparation due to their practical accessibility and controllability, while higher-order contributions are typically much weaker and treated as unwanted perturbations. Here, we alternatively show that detuned Rydberg ensembles provide a natural platform where higher-order Kerr nonlinearities can become comparable in strength to lower-orders near multiphoton resonances. We demonstrate that these nonlinearities can be harnessed as a resource for the rapid preparation of non-Gaussian states, with the coexistence of multiple Kerr orders substantially accelerating the evolution of an initial coherent state into Schrödinger cat states. Furthermore, by combining the nonlinear dynamics with a controllable linear drive, we can gain the full control over the evolution trajectory, thereby achieving cat-state generation directly from vacuum on timescales beyond the genuine Kerr evolution. Our results establish a paradigm in which naturally occurring higher-order nonlinearities are transformed from unwanted imperfections into a valuable resource for quantum state engineering.

Philip George Burke