PWM-Based Evaporative Cooling in Optical Dipole Traps
Researchers at Department of Physics and I-Hub Quantum Technology Foundation, IISER Pune introduced and demonstrated a method for cooling atoms in optical dipole traps without reducing the laser power of the dipole traps. The approach involves creating a time-averaged dipole potential by rapidly switching the optical dipole traps on and off and adjusting the duty cycle by the PWM technique at a fixed frequency via an RF switch. By optimizing the duty cycle, researchers successfully lowered and shaped the time-averaged dipole potential, facilitating atom cooling through evaporative processes.
Schematic arrangement of the PWM technique utilized for cooling atoms by time-averaged optical dipole trap.
Key Results
The temperature of cold atoms was reduced from 120 μK to 3 μK in 1 second while retaining over 10% of the atoms, achieving performance comparable to standard evaporation. The method eliminates the need for analog power control, simplifies system architecture, and supports individual trap cooling which is valuable for large-scale neutral-atom systems with 1000+ qubits.
PWM-based evaporative cooling method presents a robust, efficient, and easily implementable approach for atom cooling in optical dipole traps. In large-scale neutral atom arrays with 1000 qubits or more, this technique’s simplicity and digital control greatly reduce system complexity by removing the need for analog power control, while still allowing individual trap cooling. Lower atom temperatures also enhance photoassociation efficiency for neutral atom arrays in quantum computation, and this technique can help eliminate light shifts in precision spectroscopy.
Authors: S. Sagar Maurya, Joel M. Sunil, Monu Bhartiya, Pranab Dutta, Jay Mangaonkar, Rahul Sawant, and Umakant D. Rapol.
Read full article: https://journals.aps.org/prresearch/abstract/10.1103/fbx6-8l7n#s5