Self-induced transparency under conditions of excitation of forbidden optical transitions

Eiichi Hanamura

Ashat M. Basharov

A new type of three-level photon echo has been predicted and analytically described. In contrast to the conventional three-level echo, whose formation involves three resonant ultrashort excitation pulses spaced in time, two of which are resonant to different optically allowed and adjacent transitions with different frequencies, the echo predicted arises under the conditions of formation of the conventional two-pulse echo and requires only two pump pulses of the same frequency. A theory is developed for the conditions of experiments on generation of a superradiance pulse at the 3 P 0-3 H 6 transition in impurity praseodymium ions in the LaF3 matrix upon ultrashort coherent excitation of the adjacent optically allowed 3 H 4-3 P 0 transition in praseodymium. It is shown that the superradiance pulse after its deexcitation does not polarize the medium at the 3 P 0-3 H 6 generation transition and completely eliminates polarization at the 3 H 4-3 P 0 excitation transition. However, simultaneously, the superradiance pulse transfers the optical coherence from the excitation transition to the optically forbidden 3 H 6-3 H 4 transition. Thus, the phase memory about the effect of the excitation superradiance pulse is retained in the medium within a time interval that is shorter than the irreversible relaxation time of the optically forbidden transition.

Axel Schenzle, Hermann Haken

Matthew N. Winchester, Matthew A. Norcia, Julia Cline +1 more

In this Letter we realize a narrow spectroscopic feature using a technique that we refer to as magnetically induced optical transparency. A cold ensemble of ^{88}Sr atoms interacts with a single mode of a high-finesse optical cavity via the 7.5 kHz linewidth, spin forbidden ^{1}S_{0} to ^{3}P_{1} transition. By applying a magnetic field that shifts two excited state Zeeman levels, we open a transmission window through the cavity where the collective vacuum Rabi splitting due to a single level would create destructive interference for probe transmission. The spectroscopic feature approaches the atomic transition linewidth, which is much narrower than the cavity linewidth, and is highly immune to the reference cavity length fluctuations that limit current state-of-the-art laser frequency stability.

Naohiro Tanno

Vasily G. Arkhipkin, Ivan V. Timofeev

The spatiotemporal propagation dynamics of a weak probe pulse in an optically dense medium of three-level atoms is studied in the adiabatic approximation under conditions of electromagnetically induced transparency. The atomic coherence induced at the dipole-forbidden transitions is found to be spatially localized. This effect is used for the analysis of the reversible writing (reading) of short optical pulses. The method of pulse time reversal is suggested.