Coherent Quantum Optical Control with Subwavelength Resolution

Abstract

We suggest a new method for quantum optical control with nanoscale resolution. Our method allows for coherent far-field manipulation of individual quantum systems with spatial selectivity that is not limited by the wavelength of radiation and can, in principle, approach a few nanometers. The selectivity is enabled by the nonlinear atomic response, under the conditions of Electromagnetically Induced Transparency, to a control beam with intensity vanishing at a certain location. Practical performance of this technique and its potential applications to quantum information science with cold atoms, ions, and solid-state qubits are discussed.PACS numbers: 32.80. Qk, 42.50.Gy, 03.67.Lx Coherent optical fields provide a powerful tool for coherent manipulation of a wide variety of quantum systems. Examples range from optical pumping, cooling, and quantum control of isolated atoms [1, 2] and ions [3] to manipulation of individual electronic and nuclear spins in solid state [4,5]. However, diffraction sets a fraction of the optical wavelength λ as the fundamental limit to the size of the focal spot of light [6]. This prohibits high-fidelity addressing of individual identical atoms if they are separated by a distance of order λ or less. In this Letter, we propose a method for coherent optical far-field manipulation of quantum systems with resolution that is not limited by the wavelength of radiation and can, in principle, approach a few nanometers.Our method for coherent sub-wavelength manipulation is based on the nonlinear atomic response produced by so-called dark resonances [7]. The main idea can be understood using the three-state model atom shown in Fig.

Kerr-field-induced tunable optical atomic waveguide

“…Hence diffraction acts as a major obstacle in the generation, transfer, and processing of information. In order to subdue the effect of diffraction, variety of techniques based on Electromagnetically Induced Transparency(EIT) [8][9][10][11][12][13], Coherent Population Trapping(CPT) [14][15][16][17], and Saturated Absorption [18] have been proposed. In most of these schemes, the salient feature is to manipulate the susceptibility of the medium along the transverse direction using a spatially dependent control field.…”

Beating Difraction Limit using Dark States

“…Optical fields applied to a three-level quantum system excite the so-called dark state, which is decoupled from the fields. Similar approaches using coherent population trapping have also been developed by several groups (for example, see [20,22,23,24]). As a qualitative introduction, assume that the drive field Rabi frequency Ω d has the particular spatial distribution sketched in Fig.…”

“…The calculations reproduce the data satisfactorily. The dependence on detuning has not been considered in [20,23,24,22]. It is unique for our approach and can be understood in the following way.…”

Controllable quantum spin glasses with magnetic impurities embedded in quantum solids

“…One possibility is to rely on spectroscopic addressability 84 enabled by spatially varying magnetic fields [85][86][87] or Stark shifts [88][89][90] . Another option is to rely on the nonlinearity of the atomic response to light and thus employ techniques such as STED 91 , spin-RESOLFT 92-94 , or dark-state-based techniques [95][96][97] .…”