Design of AlN-subwavelength grating for deep ultraviolet wavelength reflector operating at 244 nm of wavelength

Highly reflective reflector (> 99.9%) operating at deep ultraviolet (DUV) wavelength region around 244 nm was proposed by using subwavelength grating (SWG) patterned AlN substrate. Structural parameters of AlN-SWG were desgined for DUV reflector using the wavenumber dispersion relation of the eiegenmdoes resulting from its periodic refractive index distribution. The electromagnetic field calculated by finite-difference time-domain (FDTD) method revealed the polarization selective reflection characteristics of the designed AlN-SWG, and the SWG can achieve more than 99% reflectivity of p-polarization (the electric field is perpendicular to the grating fingers) at the DUV wavelength of 244 nm. This extremely high reflectivity, polarization selectivity and compactness of our AlN-SWG are very useful for various DUV applications, such as cavity of DUV laser diodes.

Yuusuke Takashima, Atsuki Sasada, Kentaro Nagamatsu, Masanobu Haraguchi, and Yoshiki Naoi "Design of AlN-subwavelength grating for deep ultraviolet wavelength reflector operating at 244 nm of wavelength ", Proc. SPIE 11926, Optical Manipulation and Structured Materials Conference 2021, 1192618 (27 October 2021); https://doi.org/10.1117/12.2616175

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