Weak-Field Coherent Control of Ultrafast Molecule Making

Area of Science:

• Chemical Physics
• Quantum Control
• Ultrafast Spectroscopy

Background:

• Coherent control of ultrafast molecule formation is vital for binary photoreactions.
• Achieving control under diverse excitation conditions, including weak fields and high temperatures, is essential.
• Previous methods often required strong laser fields or specific temperature ranges.

Purpose of the Study:

• To demonstrate the feasibility of weak-field coherent control for molecule synthesis.
• To investigate the influence of laser chirp on reaction yield under realistic thermal conditions.
• To explore new pathways for coherent control of binary photoreactions (CCBP).

Main Methods:

• Experimental realization of KAr complex formation from colliding K and Ar atoms.
• Utilizing resonance-mediated two-photon excitation with weak, linearly chirped femtosecond pulses.
• Comparison of experimental findings with ab initio theoretical calculations.

Main Results:

• Successful demonstration of weak-field control over KAr complex formation.
• Enhanced product yield observed with negative laser chirp.
• Excellent agreement between experimental data and theoretical predictions.
• Confirmation of feasibility under thermally hot conditions.

Conclusions:

• Weak-field coherent control of ultrafast molecule synthesis is achievable, even at high temperatures.
• Laser chirp is a critical parameter for optimizing reaction yields in CCBP.
• This work expands the scope and applicability of coherent control strategies in chemical reactions.