Optimization of one-dimensional photonic crystals with double layer magneto-active defect

• Published in: Optical materials 2018-04, Vol.78, p.521-530
• Main Authors: Mikhailova, T.V., Berzhansky, V.N., Shaposhnikov, A.N., Karavainikov, A.V., Prokopov, A.R., Kharchenko, Yu.M., Lukienko, I.M., Miloslavskaya, O.V., Kharchenko, M.F.
• Format: Article
• Language: English
• Subjects: Faraday effect; Magneto-optical materials; Photonic crystals
• ISSN: 0925-3467; 1873-1252
• DOI: 10.1016/j.optmat.2018.03.011

Success of practical implementation of one-dimensional photonic crystals with magneto-active layers is evaluated in high values of magneto-optical (MO) quality factor Q and figure of merit F. The article relates to optimization of one-dimensional photonic crystals with double layer magneto-active (MA) defect of composition Bi1.0Y0.5Gd1.5Fe4.2Al0.8O12/Bi2.8Y0.2Fe5O12 located between the nongarnet dielectric Bragg mirrors. The structure design was performed by changing the number of layer pairs in Bragg mirrors m and the optical thickness of MA defect lM to achieve high values of MO characteristics. Theoretical predictions were confirmed by experimental investigation of eight synthesized configurations with m = 4 and m = 7. We have demonstrated the maximum Q = 15.1 deg and F = 7.5% at 624 nm for structure with m = 4 and lM = (2.5·λ0/2), where λ0 = 690 nm is the photonic band gap center. Configurations with m = 3 can also provide their effectiveness in realization. Maximum MO activity was achieved for configurations with m = 7. The structures with lM = (0.8·λ0/2) and lM = (2.5·λ0/2) showed respectively the specific Faraday rotation −113 deg/μm (that exceeds in 62 times the Faraday rotation of MA double layer film) at 654 nm and absolute Faraday rotation −20.6 deg at 626 nm. [Display omitted] •It is determined the structures showing the best magneto-optical (MO) efficiency.•Three of the eight synthesized crystals have provided the record characteristics.•Three and four pairs of layers in Bragg mirrors (m) are the most favorable for use.•Synthesized crystal with m = 4 has the MO quality factor 15.1 deg at 624 nm.•The crystals with m ≥ 5 should provide the Faraday rotation more than 20 deg.