Optical probing of atoms with a subwavelength confinement

Philippe Ballin, Isabelle Maurin, Athanasios Laliotis +4 more

Robert D. Niederriter, Chandler Schlupf, Paul Hamilton

We propose and demonstrate real-time subwavelength cavity QED measurements of the spatial distribution of atoms in an optical lattice. Atoms initially confined in one ``trap'' standing wave of an optical cavity mode are probed with a second ``probe'' standing wave. With frequencies offset by one free spectral range, the nodes of the trap fall on the antinodes of the probe in the $\ensuremath{\approx}{10}^{4}$ lattice sites around the center of the cavity. This lattice site independent atom-cavity coupling enables high sensitivity detection of atom dynamics even with atoms spread over many lattice sites. To demonstrate, we measure the temperature of $20--70\phantom{\rule{4pt}{0ex}}\ensuremath{\mu}\mathrm{K}$ atom ensembles in $<10\phantom{\rule{4pt}{0ex}}\ensuremath{\mu}\mathrm{s}$ by monitoring their expansion by $\ensuremath{\approx}100$ nm after sudden release from the trap lattice. Atom-cavity coupling imprints the atom dynamics on the probe transmission. The technique will enable improved nondestructive detection of Bloch oscillations and other atom dynamics in optical lattices.

Jared A. Miles, Diptaranjan Das, Zach J. Simmons +1 more

We report an experiment in which an atomic excitation is localized to a spatial width that is a factor of 8 smaller than the wavelength of the incident light. The experiment utilizes the sensitivity of the dark state of electromagnetically induced transparency (EIT) to the intensity of the coupling laser beam. A standing-wave coupling laser with a sinusoidally varying intensity yields tightly confined Raman excitations during the EIT process. The excitations, located near the nodes of the intensity profile, have a width of 100 nm. The experiment is performed using ultracold Rb atoms trapped in an optical dipole trap, and atomic localization is achieved with EIT pulses that are approximately 100 ns long. To probe subwavelength atom localization, we have developed a technique that can measure the width of the atomic excitations with nanometer spatial resolution.

Vlatko Balić, Michal Bajcsy, Alexander S. Zibrov +2 more

Jared A. Miles, Zach J. Simmons, Deniz D. Yavuz

We report an experiment in which an atomic excitation is localized to a spatial width that is a factor of 8 smaller than the wavelength of the incident light.The experiment utilizes the sensitivity of the dark state of electromagnetically induced transparency (EIT) to the intensity of the coupling laser beam.A standing-wave coupling laser with a sinusoidally varying intensity yields tightly confined Raman excitations during the EIT process.The excitations, located near the nodes of the intensity profile, have a width of 100 nm.The experiment is performed using ultracold 87 Rb atoms trapped in an optical dipole trap, and atomic localization is achieved with EIT pulses that are approximately 100 ns long.To probe subwavelength atom localization, we have developed a technique that can measure the width of the atomic excitations with nanometer spatial resolution.

Gerhard R. Guthöhrlein, Matthias Keller, Wulfhard K. Lange +1 more