Nonlinear and magic ponderomotive spectroscopy

TL;DR

This paper introduces nonlinear ponderomotive spectroscopy using amplitude-modulated standing waves to probe high-order Rydberg-atom transitions, achieving sub-THz frequencies and demonstrating magic-wavelength conditions for enhanced spectral precision.

Contribution

It presents the first use of nonlinear modulation in ponderomotive spectroscopy to access higher-order, dipole-forbidden transitions and establishes magic-wavelength conditions for improved measurement accuracy.

Findings

Achieved transition frequencies approaching sub-THz regime

Demonstrated magic-wavelength conditions for symmetric spectral lines

Enabled probing of dipole-forbidden transitions up to fifth order

Abstract

In ponderomotive spectroscopy an amplitude-modulated optical standing wave is employed to probe Rydberg-atom transitions, utilizing a ponderomotive rather than a dipole-field interaction. Here, we engage nonlinearities in the modulation to drive dipole-forbidden transitions up to the fifth order. We reach transition frequencies approaching the sub-THz regime. We also demonstrate magic-wavelength conditions, which result in symmetric spectral lines with a Fourier-limited feature at the line center. Applicability to precision measurement is discussed.