Effects of Spontaneously Generated Coherence on Absorption in Probe Laser in Four-level Y-type Atomic System
Ketao Liu
This paper investigates the effects of spontaneously generated coherence(SGC) on the probe absorption in the Y-type four-level atomic system driven by three fields.It finds that the probe absorption at the resonance center shows the different phenomena with the SGC effects.When SGC produces the destructive interference on the probe absorption,the absorption at the resonance center is reduced with the SGC enhancement and the gain appears there.When SGC produces the constructive interference on the probe absorption,the absorption at the resonance center is enhanced with the SGC enhancement.That is electromagnetically induced absorption(being abbreviated EIA);the intensity of double electromagnetically induced transparency(being abbreviated EIT);at both sides of the resonance is increased,and the windows get wider.At the same time,the linewidth of the absorption at the resonance center becomes narrow and the transparent windows at both sides of the resonance get wider when the spontaneous decay rate of energy levels |3〉→|2〉 and 4〉→|2〉 is decreased at the ratio of the spontaneous decay rate of energy levels |3〉→|2〉 and |4〉→|2〉 being constant.
Acta Sinica Quantum Optica•Jan 1, 2012•0 citations