Unphysical artifacts are responsible for molecular orientation with half-cycle pulses

TL;DR

This paper argues that molecular orientation using half-cycle pulses in the Terahertz range is an unphysical artifact caused by non-propagating electric field components, supported by Floquet theory calculations.

Contribution

It demonstrates that molecular orientation with half-cycle pulses is an unphysical artifact due to non-propagating electric fields, challenging previous assumptions.

Findings

Half-cycle pulses produce unphysical molecular orientation artifacts.

Floquet theory confirms the non-physical nature of these artifacts.

Such pulses cannot be used for real molecular orientation experiments.

Abstract

Sub-cycle electromagnetic pulses in the Terahertz region are considered to be one of the best ways to orient molecules. The simplest option corresponds to half-cycles pulses in the sudden regime, for which the pulse duration is much shorter than the rotational period. However, no experimental demonstration exists so far. We argue that this kind of molecular orientation is an unphysical artifact that arises from a constant component of the electric field that is not a solution of Maxwell's equations, and therefore cannot propagate with the pulse. We present calculations based on Floquet theory that prove this claim.