New facility for primary calibration of differential spectral responsivity of solar cells using LDLS-based monochromatic source

A newly established setup for primary calibration and characterization of solar cells at NMCC/SASO is presented. This differential spectral responsivity (DSR) measurement instrument uses laser-driven light source (LDLS)-based modulated (AC) source to measure the spectral responsivity of photovoltaic (PV) detectors and solar cells. The setup is intended for measuring the spectral responsivity in the wavelength range from 250 nm to 2000 nm, bias level up to 1.5 kW/m2, with which a measurement uncertainty of 1.06 % (k = 2, in the range of 300 nm to 900 nm) could be achieved. We present validation measurements as well as spectral responsivity and external quantum efficiency (EQE) measurements of reference solar cells to demonstrate the objective of the setup. We present a preliminary evaluation of the associated uncertainty components as well as an uncertainty budget for validation, optimization and standardization of our setup.

Optimization of a Polarization Nephelometer

The effect of parameters of a polarization nephelometer on its accuracy characteristic is analyzed. Errors in approximation of the actual scattering volume and actual optical beam by the elementary scattering volume and elementary beam are considered. A five-wave monochromatic source of radiation with the high spectral intensity of 0.15÷0.6 W is described. The design of polarization units is demonstrated.

Source location and evolution of the 26 s microseism from 3-C beamforming

<p><strong>Source location and evolution of the 26 s microseism from 3-C beamforming</strong></p><p>Authors: Charlotte Bruland<sup>1,</sup> Sarah Mader<sup>2,</sup> Céline Hadziioannou<sup>1</sup><br>1 Institut für Geophysik, Universität Hamburg, Germany<br>2 Karlsruher Institut für Technologie, Karlsruhe, Germany</p><p>The interest in ambient noise has increased in the recent years due to its applications in imaging and monitoring the subsurface without the use of an active source. One of the major unknowns in this field is the origin of the noise used for these analyses. Better constraints on the location and behavior of noise sources will help us understand the ocean-solid Earth interaction processes driving them and improve our applications of ambient noise. One of the most enigmatic noise sources is the 26 s microseism. This very monochromatic source has been identified in the 1960’s and seems to come from a fixed location in the Gulf of Guinea. The source mechanism of this signal is unknown.<br><br>To investigate the origin and physical mechanisms responsible for the 26 s microseism, data from permanent broadband stations in Germany, France and Algeria, and temporary arrays in Morocco and Botswana is used for spectral analysis and 3-component beamforming. The source exhibits a strong temporal variation in spectral amplitude. The signal is not always detectable, but occasionally it becomes so strong it can be detected on stations all around the world. Such burst events can last for a couple of hours up to a couple of days. From January to April 2013, the peak was detected globally 28 percent of the time. The beamforming results confirm that the energy is coming from the Gulf of Guinea, as shown in previous studies, and the direction is temporally stable. Whenever the signal is detectable, both Love and Rayleigh waves are generated. Looking into the 26 s microseism over different time periods and using different arrays, the source is expected to be temporally stable in frequency and location, but varying in energy.</p>

Multiperiodic nanohole array for high precision sensing

In this article, we present a multiperiodic nanohole array structure for improved sensing. The structure consists a series of rows of nanoholes, each having a different period in an ascending order. A monochromatic source illuminates the structure, and a resonance condition is met for the row having a momentum matching Bloch wave, which leads to extraordinary optical transmission. With this new plasmonic structure, the sensing signal can be retrieved using the spatial position of the transmission maxima. This setup requires a simple optical setup while achieving increased resolution and accuracy. A resolution of 4.6×10−6 refractive index units is achieved, which is comparable to surface plasmon resonance system based on the Kretchmann configuration.