Paper
14 May 2008 Concave diffraction gratings fabricated with planar lithography
Author Affiliations +
Abstract
This paper reports on the development and validation of a new technology for the fabrication of variable line-spacing non-planar diffraction gratings to be used in compact spectrometers. The technique is based on the standard lithographic process commonly used for pattern transfer onto a flat substrate. The essence of the technology presented here is the lithographic fabrication of a planar grating structure on top of a flexible membrane on a glass or silicon wafer and the subsequent deformation of the membrane using a master shape. For the validation of the proposed technology we fabricated several reflection concave diffraction gratings with the f-numbers varying from 2 to 3.8 and a diameter in the 4 - 7 mm range. A glass wafer with circular holes was laminated by dry-film resist to form the membranes. Subsequently, standard planar lithography was applied to the top part of the membranes for realizing grating structures. Finally the membranes were deformed using plano-convex lenses in such a way that precise lens alignment is not required. A permanent non-planar structure remains after curing. The imaging properties of the fabricated gratings were tested in a three-component spectrograph setup in which the cleaved tip of an optical fiber served as an input slit and a CCD camera was used as a detector. This simple spectrograph demonstrated subnanometer spectral resolution in the 580 - 720 nm range.
© (2008) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
S. Grabarnik, A. Emadi, H. Wu, G. De Graaf, and R. F. Wolffenbuttel "Concave diffraction gratings fabricated with planar lithography", Proc. SPIE 6992, Micro-Optics 2008, 699214 (14 May 2008); https://doi.org/10.1117/12.781057
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KEYWORDS
Diffraction gratings

Lithography

Spectrometers

Semiconducting wafers

Spectrographs

Microelectromechanical systems

CCD cameras

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