Coherent Molecular Deceleration via Vibrational Bichromatic Force

TL;DR

This paper introduces a vibrational bichromatic force method for direct laser deceleration of molecules, enabling effective cooling without relying on electronic transitions or Franck-Condon factors.

Contribution

It presents a novel vibrational transition-based deceleration scheme that suppresses spontaneous decay, applicable to any molecule with an allowed vibrational transition.

Findings

Achieved a deceleration of 1.45×10^5 m/s^2 in $^{13}$CO$_2$

Suppressed spontaneous decay and decoherence during deceleration

Demonstrated a non-dissipative, broad-applicability cooling method

Abstract

We propose a scheme for direct laser deceleration of molecules based on a vibrational transition-mediated bichromatic force (VBCF). By precisely engineering mid-infrared optical fields, we establish coherent absorption-stimulated emission cycles while exploiting the long lifetime of vibrational excited states to suppress spontaneous decay and decoherence, rendering the deceleration process effectively non-dissipative. Unlike schemes based on electronic transitions, our approach completely circumvents the restrictive Franck-Condon factors. Using the fundamental vibrational transition of $^{13}$CO$_2$ as a test case, we achieve a deceleration of $1.45\times 10^5$~m/s$^2$ with negligible population loss over the full interaction time. This VBCF framework provides a general route to cold molecules applicable to any species with an allowed fundamental vibrational transition, opening broad prospects in cold chemistry and quantum metrology.