In-Plane Optical Anisotropy of GaN Refractive Index in Visible Light Region

Dylewicz, R., Patela, S., Hogg, R.A., Fry, P.W., Parbrook, P.J., Airey, R. and Tahraoui, A. (2009) In-Plane Optical Anisotropy of GaN Refractive Index in Visible Light Region. IEEE Photonics Technology Letters, 21(14), pp. 966-968. (doi: 10.1109/LPT.2009.2021150)

Abstract

The optical properties of metal-organic chemical vapor deposition gallium nitride layers were measured with the use of a grating-assisted optical coupler. The application of a waveguide-based grating structure for in-coupling of radiated modes was the basis of the work presented here. A set of six grating couplers, providing different propagation angles with respect to the a-axis of GaN, was fabricated in a multimode GaN planar waveguide layer grown directly on c-axis (0001) sapphire. Measurements of the refractive index were carried out for laser wavelength lambda = 632.8 nm and both transverse-electric and transverse-magnetic polarized light. It was found that the refractive indices were dependent not only on the polarization state but also on the propagation direction of the excited optical mode in the plane. The 60 degree periodic in-plane anisotropy of GaN optical properties in the visible spectrum was clearly observed with maximum refractive index difference Delta n = 0.018 for both polarizations

• Item Type: Articles
• Keywords: Anisotropic Media, Chemical-Vapor-Deposition, Corrugated Waveguides, Couplers, Deposition, Electromagnetic Coupling, Fabrication, Gallium Compounds, Gallium Nitride, GaN, Gratings, Integrated Optics, Laser, Layer, Layers, Light, Nm, Optical, Optical Couplers, Optical Propagation In Anisotropic Media, Optical Waveguides, Optical-Properties, Propagation, Refractive-Index, Spectra, Wave-Guides
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Dylewicz, Dr Rafal
• Authors: Dylewicz, R., Patela, S., Hogg, R.A., Fry, P.W., Parbrook, P.J., Airey, R., and Tahraoui, A.
• College/School: College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
• Journal Name: IEEE Photonics Technology Letters
• Publisher: IEEE
• ISSN: 1041-1135