arXiv subjects

Giseok Lee

Publications and source records attributed to Giseok Lee.

3 recordsLinked to original sources

arXiv2026

Photon Cycling and Laser Cooling of an Asymmetric Top Molecule

We realize two-dimensional magnetically-assisted Sisyphus laser cooling of an asymmetric top molecule (ATM), calcium monoamide (CaNH$_2$). Vibrational state closure is achieved with $41.1 \pm 6.3$ photons scatters using optical pumping of the $X[3_1]$ state. Photon-cycling measurements show good agreement with branching ratios determined by dispersed fluorescence spectroscopy. Rotational closure is maintained by driving the $X[1_{11}] \to A [0_{00}]$ transition. The observed absence of additional state leakage channels broadens the scope of molecular laser cooling to include ATMs, which are the most general geometric class of molecules and possess the richest internal structure. Future applications of quantum controlled ATMs include new quantum information platforms and searches for physics beyond the Standard Model.

physics.atom-ph↗

arXiv2026

Spectroscopy of the $\mathbf{X^2Σ^+(v=2) \rightarrow A^2Π_{1/2}(v=1)}$ Transition in MgF: Hyperfine Structures and Spectroscopic Constants

We report spectroscopic results of the $X^2Σ^+(v=2) \rightarrow A^2Π_{1/2}(v=1)$ transition in magnesium monofluoride (MgF). Using Doppler-free Laser-Induced Fluorescence (LIF) spectroscopy on the $X^2Σ^+(v=2) \rightarrow A^2Π_{1/2}(v=1)$ transition, we resolved 47 hyperfine components distributed over 11 transition lines in X and A states. An effective Hamiltonian -- comprising contributions from vibrational, rotational, $Λ$-doubling, and hyperfine interactions -- was presented to model the energy structure of the $A^2Π_{1/2}(v=1)$ state. The spectroscopic parameters, including the rotational constant, the $Λ$-doubling parameter, and the hyperfine interaction constants, were extracted using a least-square fitting and Markov Chain Monte Carlo (MCMC) procedure. Our study reveals that the spectroscopic constants show subtle changes compared to the $A^2Π_{1/2}(v=0)$ state. These results provide critical spectroscopic benchmarks for optimizing optical cycling schemes in MgF, thereby advancing optical cycling efficiency in the magneto-optical trapping of MgF.

physics.atom-ph↗

arXiv2026

Parity-Doublet Coherence Times in Optically Trapped Polyatomic Molecules

Polyatomic molecules provide complex internal structures that are ideal for applications in quantum information science, quantum simulation, and precision searches for physics beyond the Standard Model. A key feature of polyatomic molecules is the presence of parity-doublet states. These structures, which generically arise from the rotational and vibrational degrees of freedom afforded by polyatomic molecules, are a powerful feature to pursue these diverse quantum science applications. Linear triatomic molecules contain $\ell$-type parity doublet states, which are predicted to exhibit robust coherence properties. We optically trap CaOH molecules, prepare them in $\ell$-type parity-doublet states, and realize a bare qubit coherence time of $T_2^* = 0.8(2)$ s. We suppress differential Stark shifts by employing molecular spectroscopy to cancel ambient electric fields, and characterize parity-dependent trap shifts, which are found to limit the coherence time. The parity-doublet coherence times achieved in this work are a defining milestone for the use of polyatomic molecules in quantum science.

physics.atom-ph↗