Biomedical subjects

Elisabeth Soergel

Publications and source records attributed to Elisabeth Soergel.

4 recordsLinked to original sources

PubMed2005

Large-area Fabry-Perot modulator based on electro-optic polymers.

We present a large-area electro-optic Fabry-Perot modulator utilizing a photoaddressable bis-azo polymer placed between two dielectric mirrors with an open aperture of 2 cm. A modulation efficiency of 1% at an effective modulation voltage of 20 V for a wavelength of 1.55 microm is demonstrated. By comparing distance tuning of the cavity with wavelength tuning, an effective electro-optic coefficient of -7 pm/V is measured.

Journal Article↗

PubMed2004

Light deflection from ferroelectric domain structures in congruent lithium tantalate crystals.

Congruently grown lithium tantalate crystals containing ferroelectric domain structures have been illuminated with ultraviolet light along the crystallographic c axis with simultaneous application of an external electric field. This gives rise to a star-shaped light diffraction pattern in the transmitted beam. The characteristics of this phenomenon are investigated and compared with those observed in lithium niobate crystals.

Journal Article↗

PubMed2004

Increased thermal stability of a poled electro-optic polymer using high-molar-mass fractions.

Polymer fractionation yields materials with higher average molar masses and thus substantially increased glass transition temperatures. We apply this technique to a photoaddressable polymer that exhibits high electro-optic coefficients, in order to enhance the thermal stability of the poled material. The degree of orientation of the dipolar chromophores is investigated with both pyroelectric and electro-optic measurements. The pyroelectric measurements at elevated temperatures show no significant contribution of beta relaxation as compared to alpha relaxation.

Journal Article↗

PubMed2003

Visualization of ferroelectric domains with coherent light.

Illumination of a lithium niobate or lithium tantalate crystal along the crystallographic c axis with coherent light while simultaneously applying an external electrical field through transparent electrodes allows real-time, in situ, nondestructive monitoring of ferroelectric domain patterns. Imaging of the optical near-field through a lens directly visualizes the domain walls, whereas the far-field yields averaged information about the spatial orientation of the domain boundaries.

Journal Article↗