
Pitch-variable blazed grating consisting of freestanding silicon beams
Author(s) -
Yongjin Wang,
Yoshiaki Kanamori,
Kazuhiro Hane
Publication year - 2009
Publication title -
optics express
Language(s) - Uncategorized
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.17.004419
Subject(s) - materials science , grating , blazed grating , optics , diffraction efficiency , diffraction , diffraction grating , silicon on insulator , microelectromechanical systems , etching (microfabrication) , optoelectronics , silicon , layer (electronics) , nanotechnology , physics
Theoretical analysis is presented for a pitch-variable blazed grating which consists of freestanding silicon beams. The pitch-variable blazed grating is implemented by combining silicon-on-insulator (SOI) technology with microelectronicmechanical system (MEMS) technology. The whole device is fabricated on a 10 microm silicon device layer to guarantee sufficient stiffness. The 4-level blazed surface profile is realized by combining a two-mask process with fast atom beam etching. Electrostatic combdrive microactuators with double folded springs are proposed to stretch the freestanding grating beams. In association with reactive ion etching and vapor HF release, the freestanding grating beams and the microactuators are obtained, and a Cr/Au film is deposited onto the blazed grating surfaces by a protective mask process to improve the diffracted power. Mechanical response and diffraction efficiency of fabricated devices are characterized and the experimental results indicate that the fabricated 4- level blazed gratings extend both the tuning range and the diffraction efficiency of the 1st diffraction order of present MEMS diffraction gratings.