We present the potential and the benefits of actuable micromirror arrays for large area applications for daylight
deflection. The described micromirror arrays are intended to be implemented into windows of buildings and to provide
functionalities like daylight guiding into rooms, heat regulation and glare protection. Placed between two panes of a
window, these mirrors are maintenance-free and not subject to defilement. The use of micro system technology on large
areas requires very low cost processes and materials, as well as a concept with a minimum of process steps and a very
easy and reliable process control. We present theoretical and technological approaches and first technological results.
We present an alternative method of determining the oscillating state of a laser and demonstrate the suitability of relative
intensity noise (RIN) measurements for this purpose.
The experiments were carried out using a two-section DFB laser. Optical and RIN spectra have been recorded and
correlated subsequently. The variation of the maxima of the RIN spectra have been evaluated with respect to intensity and
position in the frequency domain. Varying the frequency, a distinct transition in the above mentioned parameters can be
observed, wich can be correlated clearly to the mode degeneracy at the transition and a dominating oscillating mode below
and above. This delivers a conclusive means of determining the lasing state from RIN spectra.
Micro-opto-electromechanical systems (MOEMS) based on micromechanical mirrors can be used as key elements for
light guiding, steering and concentration. We propose micromechanical mirror arrays for light concentration on
photovoltaic modules. The semiconductor materials for solar cells are the most expensive components of a photovoltaic
system. One of the ways to reduce cost is to use light concentration by focusing sunlight onto small solar cell areas using
optical components such as lens systems. The whole system requires an external rotation mechanism to track the suns
position. As an alternative, we propose and implemented micromachined mirror arrays to concentrate light. This allows
precise dynamic light steering onto the solar cell module. These micromirror arrays can be electrostatically tuned to track
the sun position or the maximum of the brightness distribution in the sky. The micromirror arrays are located in a sealed
environment and, therefore, insensitive to external influences, such as atmosphere and wind. The advantages of the
micromachined mirrors based concentrator photovoltaic systems are dynamic light steering onto solar cells, mass
production compatibility, long lifetime and low cost. The concept of the micromachined mirror arrays will be presented.
As a new treatment model for endometriosis, photodynamic therapy was applied to endometriotic and endometrial cultures. It could be demonstrated that both endometrial components (epithelium and stroma) were present in the cultures, proved by immunocytology and electron microscopy. No major differences were seen between endometriotic and endometrial cells. The cultures were treated by HpD-sensitized PDT. Incubation time was 24 h and concentrations of 5 and 10 (mu) g/ml were used. Irradiation was performed by an argon-pumped dye laser at 630 nm with a power density of 80 mW/cm2. Evaluation both morphologically and by trypan blue exclusion test, was effected 24 h after irradiation. Toxicity in endometriotic and endometrial cultures was practically identical. Stroma cells were more sensitive to photodynamic treatment than epithelial cells. Complete stromal cell destruction was reached at 15 J/cm2, whereas epithelial cells showed 100 lethality at 40 J/cm2 (10(mu) g/ml HpD). These and subsequent results demonstrate that the sensitivity of stromal cells was about seven times higher than that of epithelial cells.
As a new treatment model for endometriosis, photodynamic therapy (PDT) was applied to endometrium cultures. Endometriosis is a benign disease. Therefore primary cultures were used instead of cell lines. Endometrium is composed of epithelial and stromal cells which can also be found in primary culture. While stromal cells take a polygonal shape in culture, epithelial cells form cell colonies. PSIII (Photasan III), which is similar to hematorporphyrin derivate (HpD), meso-tetra (4-sulfonatophenyl) porphyrin (TPPS4), which posses a high fluorescence quantum yield and may be useful in fluorescence diagnosis of subtle endometriotic spots, and methylene blue (MB), a vital dye with phototoxic properties, were used as photosensitizers. Different sensitizer concentrations and incubation times were applied. The highest phototoxicity was observed for PSIII; TPPS4 and MB were less phototoxic. We compared our results with the sensitivity of cell lines described in the literature. The necessary irradiation to destroy stromal cells was relatively high but still in the same dimension as for cell lines. However they were even more sensitive than epithelial cells. This was true for all sensitizers used.