Novel micro-optical collector design for a gas chromatographic detector based on atomic emission spectroscopy

摘要

We report a novel micro-optical systems approach for gasnchromatographic detection based on plasma excitation of the eluate andnsubsequent emission spectroscopic evaluation. Specifically, we proposena detector architecture that integrates a microhollow cathode setup andnan optical collector system on a common planar microsystems platform.nThe collector consists of an array of identical imaging systems that surroundnthe microplasma and couple the emitted light side-on into fibers vianwhich it can be fed into a spectrometer. Elliptically shaped reflector profilesnensure nearly aberration-free achromatic imaging and hence a highncoupling efficiency. This is confirmed by ray-tracing simulations. An experimentalndemonstration of the detector module is assembled. The ellipticalnprofiles are milled out of aluminium with diamond tools on an ultraprecisionnmachining center. Experimental tests with a He plasma prove thatna higher optical coupling efficieny than with the traditional end-on signalnpickup scheme can be achieved.