Integrated optical trapped-ion ground-state laser cooling with phase-stable standing waves*

Laser cooling is fundamental to quantum computation and metrology with trapped ions, and can occupy a majority of runtime in current systems. Key limitations arise from unwanted carrier excitation, which in typically used running wave (RW) fields invariably accompanies the sideband transitions effecting cooling [1]. These limitations may be bypassed via laser cooling in structured light profiles enabling selective sideband excitation with nulled carrier drive. Integrated photonic approaches' passive phase and amplitude stability [2] enable the required field profiles for example in simple and practical configurations using either standing wave (SW) or first-order Hermite-Gauss (HG) modes. In particular, quantum optical master equation simulations indicate that carrier-free electromagnetically induced transparency (EIT) cooling offers significant benefits over RW implementations simultaneously in cooling rate, motional frequency bandwidth, and final phonon number [3].

I will discuss experimental results on single-ion laser cooling in a planar ion trap with integrated photonic delivery of all wavelengths required for control of ⁴⁰Ca⁺ ions, leveraging in particular a passively phase-stable standing wave to implement both carrier-free Doppler and EIT ground-state cooling.

 

[1] J. I. Cirac, et. al., Physical Review A 46, 2668–2681 (1992).

[2] A. R. Vasquez, at. al., Physical Review Letters 130, 133201 (2023).

[3] Z. Xing and K.K. Mehta, arXiv:2411.08844 (2024).