Resonant nonstationary amplification of polychromatic laser pulses and conical emission in an optically dense ensemble of neon metastable atoms

摘要

Experimental and numerical investigation of single-beam and pump-probeinteraction with a resonantly absorbing dense extended medium under strong andweak field-matter coupling is presented. Significant probe beam amplificationand conical emission were observed. Under relatively weak pumping and highmedium density, when the condition of strong coupling between field andresonant matter is fulfilled, the probe amplification spectrum has a form ofspectral doublet. Stronger pumping leads to the appearance of a single peak ofthe probe beam amplification at the transition frequency. The greater probeintensity results in an asymmetrical transmission spectrum with amplificationat the blue wing of the absorption line and attenuation at the red one. Underhigh medium density, a broad band of amplification appears. Theoretical modelis based on the solution of the Maxwell-Bloch equations for a two-level system.Different types of probe transmission spectra obtained are attributed tocomplex dynamics of a coherent medium response to broadband polychromaticradiation of a multimode dye laser.