Refraction at the atomic level

Jian Qi Shen

A new mechanism for realizing negative refractive index with a four-level atomic system is suggested. The explicit expressions for the electric permittivity and magnetic permeability at probe frequency are presented. It is shown that there is a frequency band in which the four-level photonic-resonant atomic vapour may exhibit simultaneously negative permittivity and permeability, and that such an atomic vapour may become a left-handed material (negatively refracting medium). Compared with the previous schemes to realize negative refraction within the framework of classical electromagnetic theory, the most remarkable features of the present scenario are as follows: (i) isotropic material with microscopic structure units at atomic-scale level, (ii) negative refraction in visible and infrared frequency bands, (iii) controllable manipulation by external fields and (iv) based on quantum coherence in a multilevel atomic system.

Pierre Meystre

Hongju Guo Hongju Guo, Hongjun Zhang Hongjun Zhang, Chunfang Wang Chunfang Wang +1 more

Multicolor manipulation of negative refraction in a three-level Λ atomic system is theoretically investigated.Based on multicolor coherence, the negative refractive index can be obtained with reduced absorption.The refractive index can also be controlled by changing the sum of the phases of the sidebands in the trichromatic driving fields.By adjusting the sum phase, the refractive index can be varied between negative and positive in two different frequency bands.Furthermore, the frequency band corresponding to the negative refractive index is widened by increasing the intensity and the frequency difference of the trichromatic field.

O. N. Gadomskiĭ, Sergey G. Moiseev

Nguyen Huy Bang, Nguyen Van Phu, Vu Ngọc Sau +2 more

In this paper, we present the study on negative refractive index in an inhomogeneously broadened four-level inverted-Y atomic medium based on electromagnetically induced transparency (EIT). The expressions of the relative permittivity and the relative permeability are derived under Doppler broadening. For this four-level system, we have found two frequency bands of negative refractive index in an optical region corresponding to two EIT windows. The influences of coupling and signal laser fields as well as temperature on frequency bands of negative refractive index are investigated. Our research can be convenient for experimental implementation with real atomic media under different temperatures.