Abstract:
The possibility of the generation of a primary ultrasonic echo in the system of equidistant Zeeman triplets owing to irreversible phase relaxation has been predicted. The disappearance of phase relaxation results in the disappearance of an echo signal. This effect is due to the destructive interference of two allowed quantum transitions emitting in antiphase. The difference between the phase relaxation times at these transitions leads to an incomplete quenching of resulting coherence, leading to generation of the echo signal.