Magneto-optical trapping and sub-Doppler cooling of a polyatomic molecule

Area of Science:

• Atomic, Molecular, and Optical (AMO) Physics
• Quantum Science and Technology
• Molecular Physics

Background:

• Laser cooling and trapping, particularly magneto-optical traps (MOTs), have driven advances in Bose-Einstein condensation, quantum computation, and optical clocks.
• MOTs have been demonstrated for diatomic molecules, enabling research in quantum simulation and beyond-standard-model searches.
• Polyatomic molecules offer unique advantages for quantum applications due to their complex rotational and vibrational degrees of freedom, but have been challenging to trap.

Purpose of the Study:

• To demonstrate magneto-optical trapping of a polyatomic molecule.
• To laser cool the trapped polyatomic molecules to ultracold temperatures.
• To establish polyatomic molecules as viable candidates for quantum science applications.

Main Methods:

• Development of a magneto-optical trap (MOT) for polyatomic molecules.
• Laser cooling of trapped calcium monohydroxide (CaOH) molecules using blue-detuned optical molasses.
• Characterization of temperature and density of the trapped molecules.

Main Results:

• Successful demonstration of magneto-optical trapping for the polyatomic molecule CaOH.
• Laser cooling of CaOH molecules to 110 μK, below the Doppler cooling limit.
• Achieved temperatures and densities suitable for quantum simulation and computation applications.

Conclusions:

• Magneto-optical trapping of polyatomic molecules is feasible and practical.
• Ultracold CaOH molecules are promising for quantum simulation, computation, and beyond-standard-model searches.
• This work paves the way for trapping and cooling numerous other polyatomic species.