Spectroscopic characterization of aluminum monofluoride with relevance to laser cooling and trapping

Three-dimensional modeling magneto-optical trapping of MgF molecule with multilevel rate equations

We present a theoretical study of magneto-optical trapping (MOT) force exerted on magnesium monofluoride (MgF) with 3D rate equations, in which we have considered the complex vibrational and rotational levels and the effects of small internal splittings and degeneracies,including fine and hyperfine structures and the magnetic quantum numbers. We investigate the feasibility of MOT for MgF with a very small excited state g-factor ($g_{e} = -0.0002$) and a large radiative decay reate ($Γ = 2π\times22$MHz) for the electronic transition of X$^2Σ^{+}$ to A$^2Π_{1/2}$ states. We also optimize the MOT…

Sub-millikelvin dipolar molecules in a radio-frequency magneto-optical trap

We demonstrate a scheme for magneto-optically trapping strontium monofluoride (SrF) molecules at temperatures one order of magnitude lower and phase space densities three orders of magnitude higher than obtained previously with laser-cooled molecules. In our trap, optical dark states are destabilized by rapidly and synchronously reversing the trapping laser polarizations and the applied magnetic field gradient. The number of molecules and trap lifetime are also significantly improved from previous work by loading the trap with high laser power and then reducing the power for long-term trapping…

Magneto-optical trapping of a diatomic molecule

Laser cooling and trapping are central to modern atomic physics. The workhorse technique in cold-atom physics is the magneto-optical trap (MOT), which combines laser cooling with a restoring force from radiation pressure. For a variety of atomic species, MOTs can capture and cool large numbers of particles to ultracold temperatures (<1 mK); this has enabled the study of a wide range of phenomena from optical clocks to ultracold collisions whilst also serving as the ubiquitous starting point for further cooling into the regime of quantum degeneracy. Magneto-optical trapping of molecules could p…

Laser Cooling of Optically Trapped Molecules

Calcium monofluoride (CaF) molecules are loaded into an optical dipole trap (ODT) and subsequently laser cooled within the trap. Starting with magneto-optical trapping, we sub-Doppler cool CaF and then load $150(30)$ CaF molecules into an ODT. Enhanced loading by a factor of five is obtained when sub-Doppler cooling light and trapping light are on simultaneously. For trapped molecules, we directly observe efficient sub-Doppler cooling to a temperature of $60(5)$ $μ\text{K}$. The trapped molecular density of $8(2)\times10^7$ cm$^{-3}$ is an order of magnitude greater than in the initial sub-Dop…

分子的同位素异构体选择性激光冷却

Isotopologue-selective laser cooling of molecules

该研究以BaF为例首次实现分子的同位素异构体选择性激光冷却，在含多种高丰度同位素异构体的分子束中操控了稀有未冷却的136BaF，为低丰度同位素的强分子束与高保真检测提供可能，推动相关精密应用发展。

Laser cooling and magneto-optical trapping of molecules analyzed using optical Bloch equations and the Fokker-Planck-Kramers equation

We study theoretically the behavior of laser-cooled calcium monofluoride (CaF) molecules in an optical molasses and magneto-optical trap (MOT), and compare our results to recent experiments. We use multi-level optical Bloch equations to estimate the force and the diffusion constant, followed by a Fokker-Planck-Kramers equation to calculate the time-evolution of the velocity distribution. The calculations are done in three-dimensions, and we include all the relevant energy levels of the molecule and all the relevant frequency components of the light. Similar to simpler model systems, the veloci…

Optical cycling of AlF molecules

Aluminium monofluoride (AlF) is a promising candidate for laser cooling and trapping at high densities. We show efficient production of AlF in a bright, pulsed cryogenic buffer gas beam, and demonstrate rapid optical cycling on the Q rotational lines of the $A^1Π\leftrightarrow X^1Σ^+ $ transition. We measure the brightness of the molecular beam to be $>10^{12}$ molecules per steradian per pulse in a single rotational state and present a new method to determine its velocity distribution in a single shot. The photon scattering rate of the optical cycling scheme is measured using three different…

非粘性真空壁碰撞与可激光冷却分子

Non-stick vacuum wall collisions with a laser-coolable molecule

本文研究可激光冷却分子AlF与环境温度真空壁的碰撞，发现其存活率高，粘附概率低，可用于积累高密度分子，为紧凑便携陷阱提供途径。

连续热化学源产生AlF分子

Continuous thermochemical sources of AlF molecules

本研究利用亚熔铝三氟化物与金属铝的热化学反应，开发出连续分子束源，产生高亮度AlF分子束，用于激光离子化光谱实验，并通过低温缓冲气体降低分子旋转温度。

MgF中X²Σ⁺(v=2)→A²Π₁/₂(v=1)跃迁的光谱学：超精细结构和光谱学常数

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

研究MgF中X²Σ⁺(v=2)→A²Π₁/₂(v=1)跃迁的光谱特性，通过LIF光谱学解析11条跃迁线中的47个超精细成分，利用有效哈密顿量模型提取旋转常数、Λ-双倍参数和超精细相互作用常数，揭示光谱常数与A²Π₁/₂(v=0)态的细微差异，为优化MgF光学循环方案提供基准。