# Optical bistability in a $\Lambda$-type atomic system including near dipole-dipole interaction

## TL;DR

This paper investigates how near dipole-dipole interactions influence optical bistability in a three-level atomic system with electromagnetically induced transparency, revealing enhanced control and multistability effects.

## Contribution

It introduces the role of near dipole-dipole interactions in controlling optical bistability and multistability in a three-level EIT atomic system, extending previous two-level models.

## Key findings

- Near dipole-dipole interaction modifies absorption, dispersion, and nonlinearity.
- Optical bistability can be controlled and transitioned to multistability.
- Enhanced controllability of OB through atomic coherence and NDD effects.

## Abstract

The advantage of optical bistability (OB) using three-level electromagnetically induced transparency (EIT) atomic system over the two-level system is its controllability, as absorption, dispersion, and optical nonlinearity in one of the atomic transitions can be modified considerably by the field interacting with nearby atomic transitions. This is due to induced atomic coherences generated in such EIT system. The inclusion of near dipole-dipole (NDD) interaction among atoms further modifies absorption, dispersion, and optical nonlinearity of three-level EIT system and the OB can also be controlled by this interaction, producing OB to multistability.