# Population trapping in the excited states using vacuum-induced coherence and adiabatic process

## TL;DR

This paper theoretically explores how vacuum-induced coherence enables population trapping in excited states using adiabatic processes and delayed pulses, providing insights into quantum control and coherence phenomena.

## Contribution

It introduces a novel method combining VIC and adiabatic techniques to achieve population trapping in excited states, with potential applications in molecular systems.

## Key findings

- VIC induces a mixed state in the excited doublet.
- Population trapping persists despite large decay rates.
- Chirping can probe the coherence between excited states.

## Abstract

We theoretically investigate how population can be trapped in the excited doublet in presence of vacuum-induced coherence (VIC). We employ delayed pulses to transfer population from a metastable state to the excited states. Subsequently, spontaneous emission from the excited doublet builds coherence between them. This coherence can be probed by using chirping, which leads to the decoupling of the excited doublet from the ground state thereby ensuring population transfer via delayed pulses. Our results indicate that the existence of VIC leads to the generation of a mixed state in the excited state manifold, where trapping of the population occurs even in the presence of large decay. This trapping may be realized in molecular systems and can be understood as a sensitive probe of VIC. We present suitable numerical analysis to support our results.