The optical creation of intrinsic localized modes in perfect anharmonic lattices with realistic interatomic potentials is demonstrated theoretically, using an efficient optimal control scheme to determine experimentally feasible exciting fields. [S0031-9007(97) PACS numbers: 63.20. Ry, 63.20.Pw, 78.20.Bh Intrinsic localized modes (ILMs) are novel vibrational excitations in periodic lattices, characterized by displacement patterns which can be highly localized [1]. In contrast to localized impurity modes in harmonic defect crystals, ILMs in perfect lattices result from anharmonicity in the interparticle potentials. Recent studies have obtained ILMs for increasingly realistic models [2,3]. However, beyond a theoretical demonstration that driven ILMs can exist as a steady-state response to an applied spatially homogeneous sinusoidal driving force [4], the key experimental question of how ILMs might be created externally has not been addressed, and ILMs have not yet been verified in the laboratory. Here we describe an avenue for the experimental creation of ILMs. It is shown how ILMs can be produced in a one-dimensional model lattice with realistic potentials by means of laser pulses whose time dependence is designed by an efficient optimal control scheme. Aspects of the experimental feasibility of the approach are discussed.Owing to their high power densities, lasers are appropriate sources for exciting large-amplitude well-localized ILMs. Recent developments in experimental laser pulse shaping techniques [5,6] provide considerable flexibility in the time dependence of the applied force. Indeed, the use of tailored fields for vibrational excitation has attracted much recent interest, mainly in the context of optical control of dissociation and reactions in molecular chemistry [7], but also for the selective excitation of optical phonons in time-domain spectroscopy [8]. We will focus on two methods for transient optical creation of ILMs: impulsive stimulated Raman scattering (ISRS) excitation [9] by a sequence of femtosecond pulses at THz repetition rates from a laser operating at near visible frequencies, and infrared (IR) excitation by a picosecond far-IR laser pulse. For both mechanisms, the system's dynamical response can be described classically, provided the underlying laser frequency for the ISRS case is well off resonance with vibrational and electronic transitions.For longitudinal motion in a driven 1D system, the Hamiltonian is H X n h p 2 n 2m n 1 X l V n,n2l ͑r n 2 r n2l ͒ 2 F ext n ͑t͒r n i ,where particle n has mass m n , position r n , and momentum p n , and interacts with particle n 2 l via a potential V n,n2l . The external force is F ext n ͑t͒ 1 2 P n E 2 ͑t͒ and F ext n ͑t͒ q n E ͑t͒ for ISRS and IR excitation, respectively. Here E ͑t͒ is the longitudinally polarized electric field, P n ϵ ͑≠P ͞≠r n ͒ 0 is the electronic polarizability derivative evaluated at the equilibrium configuration, and q n is the effective charge.Our model is a 1D diatomic lattice with masses m and M ͑.m͒ and nearest-nei...