# Creating localized plasma wave by ionization of doped semiconductors

## TL;DR

This paper proposes a novel method to generate localized plasma waves by ionizing doped semiconductors with periodic dopant densities, enabling high-frequency plasma wave creation with potential applications in advanced laser amplification.

## Contribution

It introduces a new technique for creating long-lasting plasma waves using ionization of doped semiconductors, expanding the frequency range up to sub-petahertz regimes.

## Key findings

- Plasma waves can be generated with frequencies from terahertz to sub-petahertz.
- The method enables seed generation for backward Raman amplification across a wide frequency range.
- Low plasma density in solid-state materials is a key challenge for practical implementation.

## Abstract

Localized plasma waves can be generated by suddenly ionizing extrinsic semiconductors with spatially periodic dopant densities. The built-in electrostatic potentials at the metallurgical junctions, combined with electron density ripples, offer the exact initial condition for exciting long-lasting plasma waves upon ionization. This method can create plasma waves with a frequency between a few terahertz to sub-petahertz without substantial damping. The lingering plasma waves can seed backward Raman amplification in a wide range of resonance frequencies up to the extreme ultraviolet regime. Chirped wavevectors and curved wavefronts allow focusing the amplified beam in both longitudinal and transverse dimensions. The main limitation to this method appears to be obtaining sufficiently low plasma density from solid-state materials to avoid collisional damping.