# Multiphoton Femtosecond Control of Resonance-Mediated Generation of Short-Wavelength Coherent Broadband Radiation

## TL;DR

This paper presents a novel method for generating and controlling short-wavelength broadband radiation using shaped femtosecond pulses to manipulate atomic resonance-mediated three-photon excitation, advancing ultraviolet and vacuum-ultraviolet light sources.

## Contribution

It introduces a new scheme for controlling the spectral characteristics of broadband UV radiation via phase-shaped femtosecond pulses in atomic vapor, enabling precise spectral tuning.

## Key findings

- Controlled the spectrum of UV radiation by tuning the chirp of femtosecond pulses.
- Demonstrated coherent control of three-photon excitation in Na vapor.
- Paved the way for producing shaped femtosecond pulses in the vacuum-ultraviolet range.

## Abstract

We introduce a new scheme for generating short-wavelength coherent broadband radiation with well-controlled spectral characteristics. It is based on shaping long-wavelength femtosecond pulse to coherently control atomic resonance-mediated (2+1) three-photon excitation to a broad far-from-resonance continuum. Here, the spectrum (central frequency and bandwidth) of deep-ultraviolet coherent broadband radiation generated in Na vapor is experimentally controlled by tuning the linear chirp we apply to the driving phase-shaped near-infrared femtosecond pulse. This is a first step in implementing the full scheme for producing shaped femtosecond pulses at wavelengths down-to the vacuum-ultraviolet range.