Tuning the defect mode in ternary photonic crystal with external voltage for designing a controllable optical filter

• Published in: The European physical journal. D, Atomic, molecular, and optical physics Atomic, molecular, and optical physics, 2015-09, Vol.69 (9), Article 221
• Main Authors: Jamshidi-Ghaleh, Kazem, Rashidi, Shiva, Vahedi, Ali
• Format: Article
• Language: English
• Subjects: Applications of Nonlinear Dynamics and Chaos Theory; Atomic; Molecular; Optical and Plasma Physics; Physical Chemistry; Physics; Physics and Astronomy; Quantum Information Technology; Quantum Physics; Regular Article; Spectroscopy/Spectrometry; Spintronics
• ISSN: 1434-6060; 1434-6079
• DOI: 10.1140/epjd/e2015-60283-4

In this work, behavior of defect mode in one-dimensional ternary photonic crystal (1DTPC) structure with arrangement of (MgF 2 /Ag/TiO 2 ) 5 LiNbO 3 (TiO 2 /Ag/MgF 2 ) 5 was investigated under the applied external electric dc voltage. The defect layer is lithium niobate (LiNbO 3 ), an electro-optical (EO) material whose refractive index is voltage-dependent with high EO coefficient. In comparison, magnesium fluoride (MgF 2 ) and titanium dioxide (TiO 2 ) layers have very low EO coefficients. A narrow localized defect mode with perfect transmittance was appeared inside the photonic band gap. Under applying the positive or negative biases, red shift and blue shift was observed in the defect mode, respectively. More than 120 nm tunability was obtained under externally applied voltage in the range of −200 V to 200 V. The physical interpretation is very simple. Change in optical path-length displaces the localized wavelength of the defect mode due to Bragg interface condition. The externally tunable localized mode can be employed in designing a controllable optical filter, one of the essential devices for new-generation all-optical integrated circuits. Graphical abstract