RESUMO
An array of micro spectrometers for parallel spectral sensing is designed, set up and tested. It utilizes a planar prism grating combination to obtain an almost linear optical system of 6 mm length only. Arranging such micro spectrometers in an array configuration yields 2'000 spectrometers when utilizing a common 4/3" CCD image sensor well adapted to e.g. microscopic image dimensions. The application in microscopic imaging in the 450-900 nm spectral range is demonstrated as proof of concept, which can be adapted to massively parallel sensing in the frame of integrated sensor concepts.
RESUMO
In this paper we present a novel technological approach for the fabrication of multilevel gratings in the resonance domain. A coded chromium mask is used to avoid alignment errors in electron beam lithography, which typically occur within the standard multistep binary micro-optics technology. The lateral features of all phase levels of the grating are encoded in a single chromium mask. The final profile of the structure is obtained by selective etching process for each level. This new technological method is applied for the fabrication of two different three-level gratings in resonance domain. The corresponding optical response as well as structural characterizations are presented and discussed. In particular, a first order diffraction efficiency of 90% is demonstrated for a grating period twice the wavelength at normal incidence.