Synopsis: Downsizing Optical Lattices

Field patterns produced near nanoparticles could allow closely spaced traps for ultracold atoms.
Synopsis figure
M. Gullans et al., Phys. Rev. Lett. (2012)

Optical lattices formed by interfering laser beams provide a highly controllable test bench for trapping many atoms at once and studying their interactions. Because of diffraction, however, the wavelength of the trapping light limits how close the atoms can get to one another, and thus the achievable atomic density. As reported in Physical Review Letters, Michael Gullans, at Harvard University, and colleagues propose a way to overcome this limitation with subwavelength confinement of light produced by nanoplasmonic structures.

In the near field of a nanoparticle (i.e., at the distance of less than about one wavelength of a propagating wave), collective electron oscillations called plasmons can concentrate the electromagnetic field in regions much smaller than its wavelength. Gullans et al. show theoretically that the interference of an incident wave with the dipolar field it induces in a metallic particle creates a trapping region along the polarization direction of the field. In the case of silver nanospheres, slightly tuning the incident light to the blue side of an atomic resonance in rubidium should cause an atom to cling to the sphere. Arrays of nanoparticles could therefore act as anchors for an ordered lattice of ultracold atoms.

The authors suggest that with their proposed method, lattice spacings could be reduced by about an order of magnitude, from 500 nanometers down to less than 60 nanometers. Should experimentalists realize such nanoplasmonic lattices in the lab, the increased atomic density would allow the exploration of new regimes of dense, ultracold quantum matter. – David Voss


More Features »


More Announcements »

Subject Areas

Atomic and Molecular PhysicsPlasmonics

Previous Synopsis

Particles and Fields

Cosmological Hat Trick

Read More »

Next Synopsis


Tuning Casimir Forces

Read More »

Related Articles

Viewpoint: What Goes Up Must Come Down
Atomic and Molecular Physics

Viewpoint: What Goes Up Must Come Down

A molecular fountain, which launches molecules rather than atoms and allows them to be observed for long times, has been demonstrated for the first time. Read More »

Viewpoint: Matter-Light Condensates Reach Thermal Equilibrium

Viewpoint: Matter-Light Condensates Reach Thermal Equilibrium

Making use of improved microcavities, hybrid condensates of matter and light can be tuned to reach a thermal equilibrium state, despite their finite lifetime. Read More »

Synopsis: Superfluid Shielding
Atomic and Molecular Physics

Synopsis: Superfluid Shielding

Separated Bose-Einstein condensates can be shielded from external forces if immersed in a superfluid bath. Read More »

More Articles