Electromagnetically induced 2D grating via refractive index enhancement in a far-off resonant system

• Published in: Laser physics letters Vol. 14; no. 7; pp. 75202 - 75209
• Main Authors: Chen, Yu-Yuan, Liu, Zhuan-Zhuan, Wan, Ren-Gang
• Format: Journal Article
• Language: English
• Published: IOP Publishing 01.07.2017
• Subjects: diffraction grating; electromagnetically induced 2D grating; refractive index enhancement
• ISSN: 1612-2011; 1612-202X
• DOI: 10.1088/1612-202X/aa74ee

We propose a scheme for electromagnetically induced 2D grating in a mixture of two three-level Λ systems driven by two pairs of far-detuned coherent standing-wave fields. The key idea, which has been used to achieve the refractive index enhancement with vanishing absorption, is to induce two Raman resonances for the probe field, and their strength can be tuned via the two-photon detunings and the intensity of coupling field. By manipulating the absorption and gain properties of these two Raman resonances, absorption-phase grating, phase grating and gain-phase grating which effectively diffract a probe field into high-order directions can be formed in the atoms with the help of standing-wave pattern coherent fields. The diffracting power of the presented gratings strongly depends on the two-photon resonance condition and amplitude of coherent fields, hence the gratings can be used as all-optical multi-channel splitters or all-optical router in optical networking and communication.