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Optics

Division 4

Division 4 which is responsible for optics is home to three base units: that of length, time and luminous intensity. On this basis, standards and measuring methods of highest accuracy are developed for various optical quantities.

 

Tasks

Division "Optics" supports industry, science and society by providing measurement services, research and development in the field of optical technology. Based on the SI units of length, time and luminous intensity different units are realized and disseminated. Further more, accurate standards and measurement techniques are developed.

The division realizes the time scale UTC (PTB), which is the legal time in the Federal Republic of Germany, performs precision measurements in different fields of optics and cooperates in international standardisation and certification.

News

Spectral responsivity (SR) measurements are a powerful technique to measure the opto-electronic properties of photovoltaic devices like solar cells or PV modules. Although the SR determination of solar cells is a common and established technique for many years, much more effort must be taken to determine the SR of PV modules due to their size. Significantly larger and more complex solar simulator must be used, which led to a variety of different measurement techniques, each with its own disadvantages. In this work we present SR and linearity measurements performed with an LED-based solar simulator, which is capable of measuring the SR of a whole PV module within a reasonable amount of time. The principal solar simulator characteristics with its advantages and challenges are presented, including the properties of the emitted spectrum and the homogeneity of the resulting light field. The evaluation of our method, which is performed at...

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Solar simulators for PV modules often consist of several lamps arranged side by side to provide the irradiance necessary for PV module testing under standard test conditions. Since these simulators are no point sources, the angular distribution of the radiance emitted by the simulators can lead to systematic deviations in measured PV device’s performances. To quantify the opening angle of a solar simulator, pictures of a digital single-lens reflex (DSLR) camera and irradiance measurements of a CCD-array spectroradiometer were combined to derive its approximate spectral radiance distribution. We applied our technique to an LED-based solar simulator, where the radiance of 18 different LED colors could be examined separately and thus an approximation of the spectral radiance emitted by the simulator can be made. An angle of incidence of 15.6° has been observed for this system at the center of a PV module, raising to about 21.5° towards the...

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Am LENA, in Kooperation mit der TUBS und der PTB, werden nanostrukturierte GMR-Mikrofarbfilter designt, entwickelt und gefertigt. In Kombination mit CCD oder CMOS Bildsensoren sollen damit effiziente spektroskopische Sensoren für Anwendungen in Medizin und Biologie entwickelt werden. Die GMR-Farbfilter basieren auf periodischen Subwellenlängen-Metallgittern in Kombination mit einer dielektrischen Wellenleiterschicht. Die Filterfunktion wird dabei pixel-spezifisch über die Strukturparameter (z.B. Gitterperiode oder Füllfaktor) angepasst.

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