# Multiphoton Femtosecond Coherent Control in the Single-Cycle Regime

## TL;DR

This paper explores how shaped single-cycle laser pulses can coherently control two-photon absorption in atoms, emphasizing the role of carrier-envelope phase stabilization and interference of multiple pathways.

## Contribution

It introduces a theoretical framework for controlling two-photon absorption using CEP-stabilized single-cycle pulses, including a simplified model and atomic Cs verification.

## Key findings

- CEP stabilization enables full control over two-photon pathways
- Bandwidth allows for sequential and Raman-type pathway interference
- Theoretical predictions confirmed by numerical simulations in Cs

## Abstract

Coherent control of the atomic two-photon absorption with shaped single-cycle pulses is examined theoretically in the weak-field regime. The control over the stabilized carrier-envelope phase (CEP) of the pulses is determined as a key parameter allowing the full utilization of the ultrabroad pulse spectrum. This bandwidth is sufficient to provide besides the sequential two-photon pathways, additional Raman-type pathways coupling between the ground and the excited states. The interference between the different pathways is efficiently controlled via the control over the CEP. Simplified two-level model is analyzed in the frequency domain where the rational pulse shaping is applied. The developed intuition is applied to atomic Cs and verified by the exact numerical solution of time-dependent Schrodinger equation.