| Popis: |
Abstract Based on the transfer matrix theory, I realize a nearly perfect wavelength-selective absorption of near-IR waves in a one-dimensional defective photonic crystal, $$(AB)^ND(BA)^M$$ ( A B ) N D ( B A ) M , containing a vanadium dioxide (VO $$_2$$ 2 ) phase transition layer as a defect. Firstly, the effect of the period numbers, N and M, on the absorption spectrum is studied to achieve a perfect absorption peak. It is shown that optimal period numbers of the structure to maximize the absorption peak are N = 7 and M = 16. Our results also indicate that a narrow-band, almost perfect absorption is achieved due to the symmetry of the structure with respect to VO $$_2$$ 2 . Also, the absorption amount of the considered structure is about 50 times larger than that of a free-standing VO $$_2$$ 2 . Furthermore, the absorption peak value and resonant wavelength can be continuously tuned while VO $$_2$$ 2 transits from semiconductor to metal phase at 340 K temperature. In addition, how different parameters such as the polarization and incident angle affect the absorption spectra is discussed. Finally, the nonlinear absorption spectra of the structure are graphically demonstrated beside the linear case. The current system can be applied in designing practical tunable optical devices such as IR sensors, limiters, and switches. |
