Controlling the electromagnetic density of modes in one-dimensional photonic crystal with defect using acoustic wave

We have theoretically analyzed the effect of acoustic parameters on the electromagnetic density of modes (DOM) in a one-dimensional photonic crystal featuring a defect mode. The whole structure is modulated by a longitudinal acoustic wave. The transfer matrix method and Wigner time approach are used to calculate the transmittance and electromagnetic DOM, respectively. The results show that the electromagnetic DOM is dynamically controlled by the acoustic amplitude. A sharp peak in DOM is found at the defect site whose magnitude decreases with the increase in acoustic amplitude and shows periodic swing with fractional change in time period of acoustic wave. Furthermore, the result of polarization of electromagnetic wave is also discussed and it is found that the location of the defect mode can be modulated in a large frequency rage without changing the structure of the photonic crystal.