High contrast grating

The concept of high contrast grating took off with a report on a broadband high reflectivity reflector for surface-normal incident light (the ratio between the wavelength bandwidth with a reflectivity larger than 0.99 and the central wavelength is greater than 30%) in 2004 by Constance J. Chang-Hasnain et al.,[1][2] which was demonstrated experimentally in the same year.

[11][12] Fully rigorous electromagnetic solutions exist for gratings, which tends to involve heavy mathematical formulism.

Due to a large index contrast and near-wavelength dimensions, there exists a wide wavelength range where only two waveguide-array modes have real propagation constants in the z direction and, hence, carry energy.

The two modes interfere at the input and exiting plane of the high contrast grating, leading to various distinct properties.

[4][5][12][17] The light-weight of high contrast grating enables fast microelectromechanical structure actuation for wavelength tuning.

[5] The reflection phase of the high contrast grating is engineered to control the emission wavelength of vertical-cavity surface-emitting lasers.

[7][8] Applications such as slow light [19] and optical switch [20] can be built on the hollow-core waveguide by using the special phase response and resonance property of high contrast grating.