Magneto-Optical Trapping of a Metal Hydride Molecule

Area of Science:

• Atomic, Molecular, and Optical Physics
• Quantum Chemistry
• Laser Spectroscopy

Background:

• Magneto-optical traps (MOTs) are crucial for laser cooling and trapping atoms and molecules.
• Metal hydride molecules like CaH are promising candidates for precision measurements due to their complex internal structures.
• Previous efforts in trapping molecules have faced challenges with vibrational loss and dissociation.

Purpose of the Study:

• To demonstrate a three-dimensional magneto-optical trap (MOT) for the metal hydride molecule, calcium hydride (CaH).
• To investigate laser cooling techniques for molecules with vibrational loss.
• To explore the potential of CaH MOTs for precision spectroscopy and atom trapping.

Main Methods:

• Utilized a "white-light" laser cooling technique to slow a molecular beam of CaH near zero velocity.
• Loaded the slowed molecules into a radio-frequency magneto-optical trap (MOT).
• Measured the number of trapped molecules and the temperature of the MOT.

Main Results:

• Successfully demonstrated a three-dimensional MOT of CaH molecules.
• Achieved laser cooling with vibrational loss up to quantum number ν=2, scattering approximately 10^4 photons.
• Trapped 230(40) CaH molecules at a temperature below one millikelvin.
• Identified beam source characteristics and predissociative loss as limiting factors.

Conclusions:

• The developed MOT technique allows for efficient laser cooling and trapping of CaH molecules.
• The observed predissociative loss mechanism in CaH could be harnessed for controlled dissociation and optical trapping of hydrogen atoms.
• This work opens new avenues for precision spectroscopy using trapped molecules and atoms.