Generation of a wave packet tailored to efficient free space excitation of a single atom

Abstract

We demonstrate the generation of an optical dipole wave suitable for the process of efficiently coupling single quanta of light and matter in free space. We employ a parabolic mirror for the conversion of a transverse beam mode to a focused dipole wave and show the required spatial and temporal shaping of the mode incident onto the mirror. The results include a proof of principle correction of the parabolic mirror's aberrations. For the application of exciting an atom with a single photon pulse we demonstrate the creation of a suitable temporal pulse envelope. We infer coupling strengths of 89% and success probabilities of up to 87% for the application of exciting a single atom for the current experimental parameters.The final publication is available at www.epj.org.

Optical trapping of nanoparticles by full solid-angle focusing

“…Using the same methods and analysis as described in Ref. [23] an overlap η = 0.95 with an ideal dipole-mode is obtained. This value is in good agreement with the value assumed in our calculations above and demonstrates a high quality of the radially polarized mode.…”

Optical Nanofibers

“…One possibility is to use high-NA optical systems to focus light to a small spot and achieve high coupling in free space Tey et al (2008); Hétet et al (2011); Streed et al (2012). Another possibility is to use a parabolic mirror that focuses a laser such that the focused beam has the same structure as the dipole radiation pattern of a single atom, thereby increasing the ratio of the atomic area to the mode area Stobińska et al (2009) ;Golla et al (2012); Heugel et al (2012).…”

Quantifying the role of thermal motion in free-space light-atom interaction

“…We treat the motion of the atom classically and assume that the probability distribution p(T, r) is governed by a Maxwell-Boltzmann distribution with standard deviations of the positional spread of the atom σ i = k B T /mw 2 i , with i = x, y, z and mass m of 87 Rb. Equation (8) can then be evaluated by a Monte-Carlo method. Each scattered photon increases the total energy of the atom by 2E r , where E r =h 2 k 2 /2m is the photon recoil energy.…”

“…The clean energy level structure and the trapping in ultrahigh vacuum permits deriving the interaction strength with a minimum of assumptions. In a free space lightatom interface (as opposed to a situation with light fields in cavities with a discrete mode spectrum), the interaction strength is characterized by a single parameter, the spatial mode overlap Λ ∈ [0, 1], which quantifies the similarity of the incident light field to the atomic dipole mode [8,9]. The development of focusing schemes with large spatial mode overlap is a long-standing theoretical [10][11][12][13][14] and experimental challenge [4,[15][16][17][18][19][20][21][22][23].…”