Browsing by Subject "Photoresists"

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    50 nm Hall Sensors for Room Temperature Scanning Hall Probe Microscopy
    (Institute of Physics Publishing, 2004) Sandhu, A.; Kurosawa, K.; Dede, M.; Oral, A.
    Bismuth nano-Hall sensors with dimensions ∼50nm × 50 nm were fabricated using a combination of optical lithography and focused ion beam milling. The Hall coefficient, series resistance and optimum magnetic field sensitivity of the sensors were 4 × 10-4 Ω/G, 9.1kΩ and 0.8G/√Hz, respectively. A 50nm nano-Bi Hall sensor was installed into a room temperature scanning Hall probe microscope and successfully used for directly imaging ferromagnetic domains of low coercivity garnet thin films.
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    Bismuth nano-Hall probes fabricated by focused ion beam milling for direct magnetic imaging by room temperature scanning Hall probe microscopy
    (The Institution of Engineering and Technology (IET), 2001) Sandhu, A.; Masuda, H.; Kurosawa, K.; Oral, A.; Bending, S. J.
    Bismuth nano-Hall probes fabricated by using focused ion beam (FIB) milling were studied. The nano-Hall probes were used for direct magnetic imaging of domain structures in low coercivity garnets and demagnetized strontium ferrite permanent magnets. The analysis was performed using room temperature scanning Hall probe microscopy and it was found that the Bi nano-probes could overcome limitations due to surface depletion and large series resistances.
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    Laser action studies of π-conjugated polymer microcavities
    (IEEE, 2008) Tülek, Abdullah; Vardeny, Z. V.
    Unidirectional laser emission was observed from φ-conjugated polymer microcavities with spiral geometry, and from microdisks containing line defects. For both type of cavities directionality contrast of the laser emission was found to be ̃ 10, with far-field lateral divergence angle of ̃ 15°. No significant increase in the laser threshold intensity was observed compared with simple microdisk cavities. In addition we also studied the emission spectra of microring polymer lasers fabricated on nylon microfibers upon application of uniaxial stress with strain up to ̃ 12%. Substantial change in the laser emission spectrum was observed when stress was applied; showing enhanced optical sensitivity to stress larger than the changes induced in the emission spectrum caused by the microfiber diameter change. We explain the enhanced sensitivity to stress as due to the induced change in the polymer refractive index dispersion, in particular at the laser emission wavelength (̃ 635 nm).
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    Parametrically coupled multiharmonic force imaging
    (AIP Publishing, 2008) Abak, M. K.; Aktas, O.; Mammadov R.; Gürsel, I.; Dâna, A.
    We report use of nonlinear tip-sample interactions to parametrically convert the frequency components of periodic tip-sample interaction forces to frequencies where they can be resonantly detected. One flexural mode of a cantilever is used for tapping-mode imaging and another flexural mode is used for detection of forces converted in presence of an externally injected mechanical oscillation at the difference frequency of the detecting mode and a harmonic of the tapping mode. Material contrast in attractive and repulsive regimes are demonstrated on samples with polymethyl methacrylate patterns and with deoxyribonucleic acid strands on silicon. © 2008 American Institute of Physics.