Integrated photometer with porous silicon interference filters

Porous silicon transmission interference filters with laterally varying tra nsmission wavelengths are used to manufacture a photometer. Because of the linear varying transmission characteristic of the filter it is possible to measure, beyond small regions of the porous layer, the correlated spectral photo current. It is therefore necessary to bring up a series of ohmic meta l contacts along the porous filter. Between two neighbouring contacts one c an measure the spectral photo current of the transmission wavelength at thi s specific point of the surface. By measuring multiple pairs of contacts, t he whole spectrum between 400 and 1100 nm wavelength can be recorded. First results of the resolution capability and sensitivity are demonstrated. (C) 2000 Elsevier Science S.A. All rights reserved.