# Multiphoton Scattering Tomography with Coherent States

## TL;DR

This paper presents a new experimental method for characterizing the scattering properties of quantum systems using coherent states and homodyne detection, enabling detailed analysis of elastic and inelastic scattering processes.

## Contribution

It introduces a robust tomography technique that uses pulsed lasers and coherent states to efficiently probe both linear and nonlinear scattering matrices of unknown quantum systems.

## Key findings

- Method is resilient to detector noise
- Errors can be minimized by varying laser power
- Effective for both elastic and inelastic scattering analysis

## Abstract

In this work we develop an experimental procedure to interrogate the single- and multiphoton scattering matrices of an unknown quantum system interacting with propagating photons. Our proposal requires coherent state laser or microwave inputs and homodyne detection at the scatterer's output, and provides simultaneous information about multiple ---elastic and inelastic--- segments of the scattering matrix. The method is resilient to detector noise and its errors can be made arbitrarily small by combining experiments at various laser powers. Finally, we show that the tomography of scattering has to be performed using pulsed lasers to efficiently gather information about the nonlinear processes in the scatterer.