Trapped-ion laser cooling in structured light fields
Phys. Rev. Applied 24, 014034 – Published 17 July, 2025
DOI: https://doi.org/10.1103/jnty-xmjs
Abstract
Laser cooling is fundamental to quantum computation and metrology with trapped ions. In particular, quantum ground-state cooling required for many gate implementations can occupy a majority of runtime in current quantum computing systems. A key limitation to cooling arises from unwanted carrier excitation, which in typically used running-wave (RW) fields invariably accompanies the sideband excitations effecting cooling. Laser cooling in structured light profiles enables selective sideband excitation with nulled carrier drive; motivated by integrated photonic approaches’ passive phase and amplitude stability, we propose simple configurations realizable with waveguide addressing using either standing wave (SW) or first-order Hermite-Gauss modes. We quantify performance of Doppler cooling from beyond the Lamb-Dicke (LD) regime, and ground-state cooling using electromagnetically induced transparency (EIT) leveraging these field profiles. Carrier-free EIT offers significant benefits in cooling rate, motional frequency bandwidth, and final phonon numbers comparable to those achievable with resolved sideband cooling. Carrier-free Doppler cooling’s advantage is significantly compromised beyond the LD regime but continues to hold, indicating such configurations are applicable for highly excited ions. Our simulations focus on a level structure relevant to , though the carrier-free configurations can be generally applied to other species. We also quantify performance limitations due to polarization and modal impurities relevant to experimental implementation. Our results indicate potential for simple structured light profiles to alleviate bottlenecks in laser cooling, and for scalable photonic devices to improve basic operation quality in trapped-ion systems.
