The design and construction of a compact instrument that automatically measures Kerr-based third order nonlinearities
(both nonlinear refractive index: γ, and nonlinear absorption: β) in materials, is presented. The instrument includes
control of the polarization state of the input laser beam and was calibrated with well known reference samples. The
mechanical translation system and the polarizer rotation-stage are controlled via a home-made electronic circuit, whereas
the data acquisition from three photodiodes is performed by a National Instruments 12-bits DAQ. The entire system is
fully controlled by means of an application program encoded in LabView. The importance of the developed experimental
device is its reliability, compactness, easy implementation and transport, table-top installation, low cost and high
In this work we report on a fabrication method for producing large-area multilayer polymer membranes and describe its
application to the instrumentation of a deformable mirror. This implementation allows for highly flexible mirrors in
which mechanical properties vary in a controlled manner in order to better match optical requirements. In addition, the
mechanical properties of such membranes allow for a large number of closely spaced actuators. We report on the
mechanical properties of metal-polymer membranes and discuss their application to pulse shaping experiments.
In this work we present near field microwave images of microelectronic circuits and their interpretation to
complement the conventional optical analysis. We show a highly simplified design of a resonant probe with
dynamically tunable capacitive coupling and with high sensitivity. Images were obtained by measuring the
microwave reflection coefficient operating a 7 GHz. This design represents a simplified and highly effective
approach to implementing near field microwave microscopy.
We present an all-optical approach to detecting magnetization reversal events in submicron ferromagnetic structures that is non-perturbative and compatible with ultrafast optical techniques. We demonstrate experimentally that structures much smaller than the wavelength of light can be probed using both near-field and far-field laser techniques combined with a cavity Kerr enhancement technique and two different polarimetry methods. Controlled magnetization reversal events are detected in nickel magnets approaching the 100nm scale. This leads to a promising way to measure sub-picosecond dynamics of nanomagnets for fast device applications.
We present the first near-field scanning optical magneto-optic Kerr effect (MOKE) of sub-micron magnetic structures, where a Kerr rotation of 0.11° from a 0.25μm nickel magnet was observed. This is enabled by a cavity based technique to enhance the Kerr rotation of light reflected from a magnetized surface. Spatially resolved magneto-optic measurements are performed involving both conventional microscopy and near-field scanning optical microscopy (NSOM). Cavity enhancement is achieved with either a single dielectric coating or a dielectric-metal bilayer coating applied to the ferromagnetic structure of interest. We present a scattering matrix approach to calculating the enhancement resulting from a multilayer dielectric coating and show good agreement with experiment. This demonstrates a non-invasive optical technique for magnetometry with ultrahigh spatial resolution.
We have investigated the terahertz photoresponse of a single semiconductor quantum dot, electrostatically defined by a sharp conducing Atomic Force Microscope tip in contact with a resonant tunneling diode structure. The quantum dot is excited by radiation from a Free Electron Laser in experiments both at room temperature and at cryogenic temperatures. Pronounced resonant tunneling features and classical rectification at frequencies from 0.3 to 3THz are observed in the I-V curves of these devices. These results demonstrate a novel approach to achieving terahertz excitation and studying transport in quantum dots.