Constructing a light-®eld distribution for the laser guiding of atoms in photonic crystals A.V. Tarasishin, S.A. Magnitskii, V.A. Shuvaev, A.M. Zheltikov * Faculty of Physics, International Laser Center, Moscow State University, Vorob'evy gory, Moscow 119899, Russian Federation Received 30 May 2000; accepted 7 August 2000 Abstract Numerical analysis based on the ®nite-dierence time-domain simulation of the light-®eld distribution in a defect mode of a two-dimensional photonic crystal demonstrates that, with an appropriate geometry of the defect in the photonic-crystal lattice, a potential permitting the laser guiding of atoms with blue-detuned radiation can be produced. The light ®eld in a defect mode of a photonic crystal may decrease by nearly ®ve orders of magnitude on the sub- wavelength spatial scale, providing a very high localization degree of atoms, which are pushed to the center of the defect due to the dipole force. Simulations of atomic-®eld distribution and trajectories of atoms in a defect mode of a photonic crystal show that the temperatures of atoms guided by a light ®eld in photonic crystals may be much higher than temperatures characteristic of atoms guided in hollow-core ®bers. Ó 2000 Published by Elsevier Science B.V. All rights reserved. PACS: 42.70.Qs; 42.50.Vk Keywords: Photonic crystals; Laser guiding of atoms 1. Introduction The ability of photonic crystals, or photonic band-gap (PBG) structures, to stop and localize light is well known [1]. They are widely discussed now in the context of dierent problems of optics and photonics [2], including the creation of optical delay lines [3], switches [4±6], pulse compressors [7], frequency converters [8±10], and elements of near-®eld microscopy [11]. Dispersion properties of PBG structures allow many classical problems of nonlinear optics to be solved in a very ecient way, as group and phase mismatches in nonlinear- optical interactions can be substantially reduced in PBG structures and the eciency of frequency conversion can be considerably improved [8± 10,12]. A defect introduced in a photonic-crystal lattice provides additional degrees of freedom in controlling and localizing the light ®eld, opening new ways of implementing low-loss light guiding and bending [13], as well as subwavelength light- ®eld localization and evanescent-wave formation [14]. This paper focuses on yet another remarkable property of photonic crystals that has not been fully appreciated so far ± the ability of defect modes of PBG structures to guide and manipu- late atoms. The laser guiding of atoms in such 15 October 2000 Optics Communications 184 (2000) 391±396 www.elsevier.com/locate/optcom * Corresponding author. Fax: +7-95-93-93-113. E-mail address: zheltikov@top.phys.msu.su (A.M. Zhelti- kov). 0030-4018/00/$ - see front matter Ó 2000 Published by Elsevier Science B.V. All rights reserved. PII:S0030-4018(00)00942-1