Enhanced Pauli blocking of light scattering in a trapped Fermi gas

TL;DR

This paper investigates methods to enhance the visibility of Pauli blocking effects in light scattering within a trapped Fermi gas, demonstrating increased suppression through focused illumination and internal state imbalance at low temperatures.

Contribution

It introduces two new approaches—focused excitation and internal state imbalance—to improve Pauli blocking detection in trapped Fermi gases.

Findings

Focusing light increases Pauli blocking signature by 14%.

Spontaneous Raman scattering can be fully suppressed at low temperatures.

Blocking is most effective when the Fermi energy exceeds four times the recoil energy.

Abstract

Pauli blocking of spontaneous emission by a single excited-state atom has been predicted to be dramatic at low temperature when the Fermi energy $E_\mathrm{F}$ exceeds the recoil energy $E_\mathrm{R}$. The photon scattering rate of a ground-state Fermi gas can also be suppressed by occupation of the final states accessible to a recoiling atom, however suppression is diminished by scattering events near the Fermi edge. We analyze two new approaches to improve the visibility of Pauli blocking in a trapped Fermi gas. Focusing the incident light to excite preferentially the high-density region of the cloud can increase the blocking signature by 14%, and is most effective at intermediate temperature. Spontaneous Raman scattering between imbalanced internal states can be strongly suppressed at low temperature, and is completely blocked for a final-state $E_\mathrm{F} > 4 E_\mathrm{R}$ in the high imbalance limit.