Photoassociation spectroscopy of weakly bound $^{87}Rb_{2}$ molecules near $5P_{1/2} +5S_{1/2}$ threshold by optical Bragg scattering in Bose-Einstein condensates

TL;DR

This study uses optical Bragg scattering to perform high-resolution photoassociation spectroscopy on $^{87}Rb$ BECs, revealing new excited molecular states near the dissociation limit with high precision and confirming results with traditional methods.

Contribution

It introduces a novel high-resolution spectroscopy method using optical Bragg scattering for $^{87}Rb$ BECs, identifying previously unreported excited molecular states near the dissociation limit.

Findings

High-resolution PA spectrum obtained with optical Bragg scattering.

Results agree well with conventional trap loss method.

Discovery of new excited molecular states near the dissociation limit.

Abstract

We report the high resolution photoassociation (PA) spectroscopy of a $^{87}Rb$ Bose-Einstein condensate (BEC) to excited molecular states near the dissociation limit of $5P_{1/2} +5S_{1/2}$ by optical Bragg scattering. Since the detection of optical Bragg scattering in BEC has a high signal-noise ratio, we obtain the high resolution PA spectrum of excited molecular states in the range of $\pm1$ GHz near the dissociation limit of $5P_{1/2} +5S_{1/2}$. We compare the results with the conventional method of trap loss and show that the results agree each other very well. Many interesting phenomena of excited molecular states are observed, such as light-induced frequency shift and the anomalous strong bound molecular lines at the atomic transition from $|F=1\rangle$ to $|F^{\prime}=2\rangle$. The observed excited molecular states in the range of $\pm1$ GHz near the dissociation limit of $5P_{1/2} +5S_{1/2}$ are never reported before, which will help to further improve the long range bound state models near the dissociation limit.