Our article on optical precursors is out now, visit the abstract at:
Carrier-frequency dependence of a step-modulated pulse propagating through a weakly dispersive single narrow-resonance absorber
Near a narrow resonance, an optical pulse can pass through a strongly-absorbing atomic vapor for the first few nanoseconds. The part of the pulse that makes it through the material is called a precursor. Our paper explores the form of the precursors as the carrier frequency is tuned off resonance.
Experimentally obtained transient transmission intensity (black solid lines) compared with two theoretical analysis: the asymptotic analysis (red dotted lines), and the weakly dispersive narrow resonance (blue dashed lines). Transient transmission taken near the 4S1/2 (F = 1) ↔ 4P1/2 (F = 2) transition for (a) ∆ = ∆(1) ∼ 5δ, (b) ∆ = ∆(2) ∼ δ, and (c) ∆ = ∆(3) ∼ 0.