Events

Bright, tunable sources of narrow-band THz radiation are highly desirable for studies of low energy excitations of various systems such as phonons, strongly correlated electron systems, and the rotational and vibrational states of molecules. Techniques developed so far to obtain narrow-band THz pulses include mixing chirped optical pulses in a photoconductive switch; optical rectification of shaped pulses; and optical rectification in quasi-phase matching nonlinear crystals.

For more information, please see www.physics.oregonstate.edu/TeachSeminar

Wide band gap semiconductors are important elements in a new class of applications that can be broadly categorized as transparent t electronics. They are used as transparent electrodes, insulators, and active layers (e.g. channel layers in transistors or light emitters in diodes). In this talk, I will focus on chalcogenides, s, oxy-chalgogenides, and chalogenide fluorides as examples of such materials.

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For more information, please see www.physics.oregonstate.edu/TeachSeminar

Laser processes have been applied to microscale to nanoscale technologies where wafer level laser micromachining or surface processing of silicon, glass, and other materials are crucial steps to realize the potential of new products or their developments. Especially, the laser processing of silicon using nanosecond laser pulses provides the capabilities of high precision and fast processing in micromachining applications.

The phrase "research and development" apart from its conventional meaning of scientific research and technological development has a special commercial significance and may be thought of as "activities conducted by specialized units or centers belonging to companies, universities and state agencies". These activities are usually future-oriented, longer-term, and without predetermined outcomes and with broad hope of commercial yield.

For more information, please see www.physics.oregonstate.edu/TeachSeminar

My research is focused on applying photodynamic therapy (PDT) towards bone cancers. In PDT, inert photosensitizers (PS) are administered to targeted areas for treatment. Once illuminated by wavelengths specific to the absorption properties of each PS, the PS reaches an excited state and interacts with nearby oxygen, forming reactive species and free radicals. The reactive oxygen and free radicals then damage nearby cells. The goal of PDT is to create sufficient free radicals and reactive oxygen to destroy targeted sites.

Semiconducting carbon nanotubes are extremely sensitive to their electrostatic environment. We use this property to build single-nanotube sensors in liquid environments that detect bio-molecule adsorption in real time via changes in device conductivity. The mechanisms for conductance modulation upon adsorption have been controversial. I will present scanned probe measurements and liquid gating measurements that resolve much of this controversy. We show how modulation of Schottky barrier contacts, together with bulk doping of the nanotubes, lead to gate-dependant changes in conductivity.

For more information, please see www.physics.oregonstate.edu/TeachSeminar

There has been considerable interest in the potential application of terahertz (THz) time domain spectroscopy (TDS) for a variety of problems, including the detection of explosive devices and imaging for biomedical applications. The THz regime has many advantages, including the possibility of a safe (non-ionizing) screening modality and the potential for high-resolution 3D imaging. It also has the advantage of exhibiting spectral peaks that can be used, for example, to classify explosives or detect the presence of cancerous cells.