The time evolution of the inversion S3(t) for a sin-squared pulse. The excitation is on-resonance, i.e., ω = ω10, the pulse area is θ = Π, and φ= 0. (a) np= 10, (b) np= 3, (c) np= 2, and (d) np= 1. Solid curve: N = 109cm−2, dotted curve: N = 3 × 1011cm−2, dashed curve: N = 5 × 1011cm−2, and dot-dashed curve: N = 7 × 1011cm−2.
Paspalakis and Boviatsis Nanoscale Research Letters 2012 7:478 doi:10.1186/1556-276X-7-478