# Exploring the Optical States for Black Phosphorus: Anisotropy and Bandgap Tuning

## TL;DR

This paper investigates how anisotropic black phosphorus's electronic states are affected by off-resonant electromagnetic radiation, focusing on bandgap tuning and anisotropy modification using theoretical calculations.

## Contribution

It provides a detailed analysis of dressed states in anisotropic black phosphorus under various polarizations, highlighting novel renormalization effects and tunable anisotropy.

## Key findings

- States depend on polarization and layer number
- Renormalization differs from previous Dirac structures
- Anisotropy can be modified in all directions

## Abstract

The dressed states arising from the interaction between electrons and holes, and off-resonant electromagnetic radiation have been investigated for recently fabricated gapped and anisotropic black phosphorus. Our calculations were carried out for the low-energy electronic subbands near the $\Gamma$ point. States for both linear and circular polarizations of the incoming radiation have been computed. However, our principal emphasis is on linearly polarized light with arbitrary polarization since this case has not been given much attention for dressing fields imposed on anisotropic structures. We have considered various cases for one- and few-layer phosphorus, including massless Dirac fermions with tunable in-plane anisotropy. Initial Hamiltonian parameters are renormalized in a largely different way compared to those for previously reported for gapped Dirac structures and, most importantly, existing anisotropy which could be modified in every direction.