# Optical Transistor for an Amplification of Radiation in a Broadband THz Domain

## TL;DR

This paper introduces a novel graphene-superconductor hybrid optical transistor that amplifies broadband THz radiation through surface plasmons and quantum capacitance, enabling amplification of chaotic signals for biological uses.

## Contribution

It presents a new hybrid device design that achieves broadband THz amplification using surface plasmons and quantum capacitance effects.

## Key findings

- Achieves positive gain in THz amplification.
- Demonstrates amplification of chaotic signals.
- Operates as an optical transistor in the THz domain.

## Abstract

We propose a new type of optical transistor for a broadband amplification of THz radiation. It is made of a graphene--superconductor hybrid, where electrons and Cooper pairs couple by Coulomb forces. The transistor operates via the propagation of surface plasmons in both layers, and the origin of amplification is the quantum capacitance of graphene. It leads to THz waves amplification, the negative power absorption, and as a result, the system yields positive gain, and the hybrid acts like an optical transistor, operating with the terahertz light. It can, in principle, amplify even a whole spectrum of chaotic signals (or noise), that is required for numerous biological applications.