ABSTRACT
We describe a variable path length waveguide setup developed to accurately measure the complex dielectric permittivity of liquids. This is achieved by measuring the complex scattering parameter of the liquid in a waveguide section with a vector network analyzer in combination with an E-band frequency converter. The automated measurement procedure allows fast acquisition at closely spaced intervals over the entire measurement bandwidth: 60-90 GHz. The presented technique is an absolute method and as such is not prone to calibration errors. The technique is suited to investigate low-loss as well as high-loss liquids in contrast to similar setups described previously. We present measurements for a high-loss liquid (water), an intermediate-loss sample (ethanol), and for nearly loss-less n-octane. Due to the available phase information, the present data have an improved accuracy in comparison with literature data.
ABSTRACT
We describe the realization of a phase-sensitive and ultrafast near-field microscope, optimized for investigation of surface plasmon polariton propagation. The apparatus consists of a homebuilt near-field microscope that is incorporated in Mach-Zehnder-type interferometer which enables heterodyne detection. We show that this microscope is able to measure dynamical properties of both photonic and plasmonic systems with phase sensitivity.
Subject(s)
Interferometry/instrumentation , Microscopy, Scanning Probe/instrumentation , Surface Plasmon Resonance/instrumentation , Equipment Design , Equipment Failure Analysis , Interferometry/methods , Microscopy, Scanning Probe/methods , Reproducibility of Results , Sensitivity and Specificity , Surface Plasmon Resonance/methodsABSTRACT
We present the design and testing of a rotating device that fits within a commercial helium cryostat and is capable of providing at 4 K a fresh sample surface for subsequent shots of a 1-10 kHz amplified pulsed laser. We benchmark this rotator in a transient-absorption experiment on molecular switches. After showing that the device introduces only a small amount of additional noise, we demonstrate how the effect of signal degradation due to high fluence is completely resolved.
Subject(s)
Artifacts , Freezing , Specimen Handling/instrumentation , Spectrophotometry, Ultraviolet/instrumentation , Equipment Design , Equipment Failure Analysis , Reproducibility of Results , Sensitivity and Specificity , Specimen Handling/methods , Spectrophotometry, Ultraviolet/methods , Time FactorsABSTRACT
A brief description is given of the design principles and layout of the Dutch-Belgian beamline at the ESRF. This beamline optimizes the use of the available bending-magnet radiation fan by splitting the beam into two branches, each accommodating two experimental techniques.
