Rene Dändliker

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We discuss the realization of highly efficient fan-out elements. Laser-beam writing lithography is available now for fabricating smooth surface relief microstructures. We develop several methods for optimizing microstructure profiles. Only a small number of parameters in the object plane are necessary for determining the kinoform. This simplifies the(More)
A coherent photon scanning tunneling microscope is presented. The setup employs heterodyne interferometry, allowing both the phase and the amplitude of the optical near field to be measured. Experimental results of measurements on a standing evanescent wave reveal the high resolution that is obtainable with such an approach. In fact we have measured the(More)
Micro-optical systems based on refractive microlenses are investigated. These systems are integrated on a chemical chip. They focus an excitation beam into the detection volume (microliter or even submi-croliter scale) and collect the emitted light from fluorescent molecules. The fluorescence must be carefully separated by spatial and spectral filtering(More)
We have extended the use of a dispersive white-light interferometer for absolute distance measurement to include effects of dielectric multilayer systems on the target. The phase of the ref lected wave changes as a function of wavelength and layer thickness and causes errors in the interferometric distance measurement. With dispersive white-light(More)
High Resolution Interference Microscopy (HRIM) is a technique that allows the characterization of amplitude and phase of electromagnetic wave-fields in the far-field with a spatial accuracy that corresponds to a few nanometers in the object plane. Emphasis is put on the precise determination of topological features in the wave-field, called phase(More)
Conditions in the inner ear for interferometric measurements are quite different from those encountered in other mechanical systems: (i) The inner ear is not mechanically stable, due to blood pulsations and breathing artifacts; (ii) access to the inner ear is limited by anatomical constraints that make it difficult to visualize the structures of interest;(More)
We propose a new tunable laser source concept for multiple-wavelength interferometry, offering an unprecedented large choice of synthetic wavelengths with a relative uncertainty better than 10(-11) in vacuum. Two lasers are frequency stabilized over a wide range of frequency intervals defined by the frequency comb generated by a mode-locked fiber laser. In(More)
In two-wavelength interferometry, synthetic wavelengths are generated in order to reduce the sensitivity or to extend the range of unambiguity for interferometric measurements. Here a novel optoelectronic technique, called superheterodyne detection, is presented, which permits measurement of the phase difference of two optical frequencies that cannot be(More)
We describe a signal-processing method for determining the center position of a white-light fringe signal. This is achieved in two steps. First, the center of gravity of the signal power is calculated to better than half a fringe period. Second, a synchronous sampling with four samples per fringe period is used to calculate the phase of the zero fringe. The(More)
The recording of efficient fan-out elements as volume holograms is investigated by using the coupled-wave theory. In contrast to the results published in the standard literature, we find that the efficiency and the uniformity of regular fan-out elements depend strongly on the relative phases of the object waves, at least, if the thickness of the hologram is(More)