Wave propagation and dispersion in space-time periodic media

Optical isolation based on space-time engineered asymmetric photonic band gaps

“…This permittivity represents a periodic Bragg structure whose spatial profile moves in time at the modulation velocity v m . Related space-time periodic media were first studied in the context of traveling-wave parametric amplification and parametric energy conversion [46][47][48][49][50][51][52]. The electric field in such a medium satisfies the following wave equation [50]:…”

Protecting MRI rooms by dielectric diffraction gratings

“…Several different techniques have been used to analyze the diffraction of electromagnetic waves by spatially modulated media. The most common of these methods are the coupled-wave approach and the modal approach [14][15][16][17][18][19][20].…”

Negative refraction and photonic-crystal optics in a cold gas

“…The number of different FB modes with the same value of k z and their propagation directions can be deduced from the equi-frequency surface (EFS) for Eq. (4) in the k x , k z plane [10,14,15]. Fig.…”

“…Normals to the EFS (depictes by arrows in Fig. 1(c)) determine the group velocity directions of these modes [10,14,15]. Figure shows that for k z0 close to π/a there are two normal modes with positive x-component of the group velocity: an N-mode (with k x ≡ k N , point C) and a P-mode (with k x ≡ k P , point B).…”

“…Applying modal approach [15], we find an analytical solution for the Maxwell equations for TE-polarized waves, E = (0, E, 0), H = (H x , 0, H z ), as follows. Due to periodicity along z, the eigenstates are Floquet-Bloch (FB) modes [14] consisting of partial waves (marked by index m) of the form…”