Photonic devices having degenerate spectral band edges and methods of using the same
View Patent ↗Provided herein are photonic devices configured to display photonic band gap structure with a degenerate band edge. Electromagnetic radiation incident upon these photonic devices can be converted into a frozen mode characterized by a significantly increased amplitude, as compared to that of the incident wave. The device can also be configured as a resonance cavity with a giant transmission band edge resonance. In an exemplary embodiment, the photonic device is a periodic layered structure with each unit cell comprising at least two anisotropic layers with misaligned anisotropy. The degenerate band edge at given frequency can be achieved by proper choice of the layers' thicknesses and the misalignment angle. In another embodiment, the photonic device is configured as a waveguide periodically modulated along its axis.
1. A photonic device, comprising:
a periodic structure having an electromagnetic dispersion relation that exhibits a frequency gap with a degenerate band edge for an input electromagnetic wave propagating in a first direction, wherein the structure is periodic in the first direction, wherein the structure is configured as an electromagnetic waveguide comprising a plurality of periodic segments and wherein the first direction is a Z direction and each segment has a variable cross-sectional shape measured along a X-Y plane formed by an X direction and a Y direction, the X direction being perpendicular to the Z direction and the Y direction being perpendicular to the X and Z directions.
2. The photonic device of claim 1 , wherein the structure is a fiber configured to operate over a frequency range in the optical portion of the electromagnetic spectrum.
3. The photonic device of claim 1 , wherein the cross-sectional shape of at least a portion of each segment is anisotropic in the X-Y plane.
4. A photonic device, comprising:
a periodic structure having an electromagnetic dispersion relation that exhibits a frequency gap with a degenerate band edge for an input electromagnetic wave propagating in a first direction, wherein the structure is periodic in the first direction, wherein the structure is configured as an electromagnetic waveguide comprising a plurality of periodic segments and wherein each of the segments comprises a first portion and a second portion located successively along the first direction, the first portion comprising a first non-uniform material and the second portion comprising a second non-uniform material, wherein the first portion has an anisotropy in the X-Y plane misaligned from an anisotropy of the second portion.
5. The photonic device of claim 4 , wherein each of the segments comprises a third isotropic in the X-Y plane portion.