title: Optical imaging module for astigmatic detection system.
abstract: In this paper, an optical imaging module design for an astigmatic detection system (ADS) is presented. The module is based on a commercial optical pickup unit (OPU) and it contains a coaxial illuminant for illuminating a specimen. Furthermore, the imaging module facilitates viewing the specimen and the detection laser spot of the ADS with a lateral resolution of approximately 1 μm without requiring the removal of an element of the OPU. Two polarizers and one infrared filter are used to eliminate stray laser light in the OPU and stray light produced by the illuminant. Imaging modules designed for digital versatile disks (DVDs) and Blu-ray DVDs were demonstrated. Furthermore, the module can be used for imaging a small cantilever with approximate dimensions of 2 μm (width) × 5 μm (length), and therefore, it has the potential to be used in high-speed atomic force microscopy.
authors.affiliation: Institute of Physics, Academia Sinica, Taipei 11529, Taiwan.
authors.forename: Wei-Min
authors.initials: WM
authors.lastname: Wang
authors.affiliation: Institute of Physics, Academia Sinica, Taipei 11529, Taiwan.
authors.forename: Chung-Hsiang
authors.initials: CH
authors.lastname: Cheng
authors.affiliation: Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116 Braunschweig, Germany.
authors.forename: Gabor
authors.initials: G
authors.lastname: Molnar
authors.affiliation: Institute of Physics, Academia Sinica, Taipei 11529, Taiwan.
authors.forename: Ing-Shouh
authors.initials: IS
authors.lastname: Hwang
authors.affiliation: Department of Mechanical Engineering, National Taiwan University, Taipei 10617, Taiwan.
authors.forename: Kuang-Yuh
authors.initials: KY
authors.lastname: Huang
authors.affiliation: Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116 Braunschweig, Germany.
authors.forename: Hans-Ulrich
authors.initials: HU
authors.lastname: Danzebrink
authors.affiliation: Institute of Physics, Academia Sinica, Taipei 11529, Taiwan.
authors.forename: En-Te
authors.initials: ET
authors.lastname: Hwu