Manuela Hofmann

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We present a novel technique for ultrafast on-off switching and wavelength tuning of an external-cavity laser diode (ECLD) using an intracavity reflective electroabsorption modulator array as the end mirror. on-off and wavelength switching of the ECLD are based upon the electrically induced control of the modulator's reflectivity yielding a modulation of(More)
Organic light emitting diodes (OLED) are the basic components of a new display generation. They are convincing compared to liquid crystal displays (LCD) by a higher contrast ratio and smaller power consumption. Additionally, these luminescent elements can be produced ultra-thin. "Conventional" OLEDs are usually processed on glass and provided with an(More)
For the first time an external cavity laser diode whose operating wavelength is controlled by an array of vertical electro-absorption modulators (EAM) is successfully demonstrated. It provides wavelength switching, intensity modulation und multiple wavelengths lasing due to purely electronical control of the EAMs. Fast on-off switching as well as wavelength(More)
In this paper, a vertical pin-modulator is described, which replaces the standard backside mirror of the external cavity in a Littman-type laser system. By controlling the reflectivity of the pin-modulator the power of the output beam can be modulated. A pin-modulator with a reflectance contrast of about 4 dB leads to a contrast of more than 22 dB of the(More)
The loss of visualization in neuroendoscopy due to intraoperative bleeding is called “red out”. Although red out is a well-known problem during endoscopy, clear physical descriptions of this phenomenon are lacking. The aim of this study was to investigate the optical properties of red out. In particular, the attenuation coefficient, comprising scattering,(More)
BACKGROUND Patients and medical personnel are eager to use blood glucose meters that are easy to handle and fast acting. We questioned whether accuracy and precision of these new, small and light weight devices would meet analytical laboratory standards and tested four meters with the above mentioned conditions. METHODS Approximately 300 capillary blood(More)
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