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Remarks on “group velocity, negative and ultra‐high index of refraction in photonic band gap materials”
Author(s) -
Gómez Alvaro,
Vegas Angel,
Solano Miguel A.
Publication year - 2004
Publication title -
microwave and optical technology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.304
H-Index - 76
eISSN - 1098-2760
pISSN - 0895-2477
DOI - 10.1002/mop.20617
Subject(s) - refractive index , group velocity , microwave , negative refraction , optics , photonic crystal , physics , dispersion relation , phase velocity , photonics , dispersion (optics) , negative index metamaterials , condensed matter physics , quantum mechanics
In the paper of Ojha et al. (Microwave Opt Technol Lett 42 (2004), 82–87), an erroneous definition of the effective refractive index n eff in a photonic band gap (PBG) structure is used. The effective refractive index n eff is defined as a function of the group velocity; this suffers from two main errors: firstly, the concept of group velocity is not useful in regions of anomalous dispersion, and this is just the region of interest for the calculus in Ojha et al. (Microwave Opt Technol Lett 42 (2004), 82–87) of n eff of the PBG structure, and secondly, in any case the refractive index has to be defined in terms of the phase velocity. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 44: 302–303, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20617