Optimized tunable Alvarez-Lohmann-lenses

In the late 1960s Alvarez and Lohmann independently suggested cubic phase plates as varifocal elements. A variety of different theoretical as well as experimental approaches have been discussed since. Today compact tunable optics is of specific interest e.g. in miniaturized optical systems. Recently developed fabrication technologies like diamond turning or milling nowadays enable the fabrication of higher order freeform surface profiles as implementation of efficient phase plates for an optimization of the imaging properties. We present a non-paraxial analysis of the imaging behavior of diffractive, refractive and hybrid Alvarez-Lohmann lenses with increased numerical aperture. Our analysis includes the influence of lateral focus shifts as well as monochromatic and polychromatic aberrations over the tuning range. Experimental results with phase plates fabricated by diamond milling and lithographic techniques will be presented

Design and integration of a multi-channel fluorescence detector

In combination with fluidic systems, fluorescence detectors have a large variety of applications e.g. in biomedicine for ph-sensoring or the characterization of chemical reaction processes. Highly integrated and miniaturized optofluidic microsystems enable the handling of very small sample volumes in so-called segmented flow systems, which is beneficial for the practical application. A single-channel fluorescence sensor using planar integrated free space optical systems has been developed in the past. In order to increase the measuring flexibility and accuracy the extension to a multi-wavelength and multi-channel sensor system based on this concept is currently investigated. We present the concept, optical design and fabrication strategy of a highly integrated free space optical fluorescence detector for the application in a segmented-flow environment. The performance of the system is characterized and the application as a biochemical analysis system is discussed

Parallelisierte chromatisch-konfokale Mikroskopie mit einem Mehrkanalspektrometer

Die konfokale Mikroskopie ist ein weit verbreitetes Verfahren der industriellen Messtechnik. Wir präsentieren ein chromatisch-konfokales Messsystem, das sich eines Farblängsfehlers zur parallelen Erfassung der Tiefeninformationen an mehreren lateralen Messpunkten bedient. Die Auswertung der Messdaten erfolgt mit einem Mehrkanalspektrometer

Planar integrated free-space optical fluorescence detector for micro fluidic applications

Based on the planar integrated free space optical systems approach the design and manufacturing results of a fluorescence detector are presented. The system is fabricated by micro milling on a KUGLER microgantry® 5x milling machine. The fluorescence detector is designed for the integration into the segmented flow environment for pH-sensing in fluid segments