Entwicklung einer Transient Photocurrent Response-Methode zur zerstoerungsfreien Untersuchung von Stoerstellen in Solarzellen

Es wird ein neues Messverfahren zur zerstoerungsfreien Charakterisierung von Verunreinigungen in der Basis grossflaechiger [(20x20) mm"2] Solarzellen bzw. Photodetektoren vorgestellt. Bei diesem TPCR-Messverfahren wird das durch eine repetierende, rechteckfoermige, monochromatische Bestrahlung erzeugte transiente Photostrom-Signal in Abhaengigkeit von der Dunkelzeit zwischen den Bestrahlungspulsen und von der Temperatur der Zelle aufgenommen. (orig./HW)A new measuring method for the destruction-free characterisation of impurities in basically large-surface [(20 x 20) mm"2] solar cells or photo detectors is explained. During this TPCR measuring method the transient photocurrent signal, generated by a repeating, rectangular, monochromatic irradiation, is recorded in dependence on the darkness between the irradiation pulses and on the temperature of the cells. (orig.)SIGLEAvailable from TIB Hannover: RA 3254(46) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Ein transportables optisches Calcium-Frequenznormal

In the course of this dissertation, a transportable optical frequency standard has been developed and characterized to disseminate the frequency of the calcium intercombination line at #lambda# #approx# 657 nm. The key components of the transportable frequency standard are a miniaturized thermal calcium beam apparatus and a frequency-stabilized diode laser system. A specially designed diode laser system in an extended cavity configuration was set up as a prerequisite to achieve the required narrow laser linewidth. The laser frequency was then stabilized to an eigenfrequency of a high finesse Fabry-Perot cavity by using frequency modulation spectroscopy. As a result, the frequency noise of the laser system was drastically reduced leading to a laser linewidth of below 2 kHz within an observation time of up to 1 s. For the long term stability, the laser frequency was stabilized to the intercombination line of atomic calcium. To suppress the interaction-time-broadening caused by the high velocities of the Ca-atoms in the effusive beam, a separated-field excitation scheme (optical Ramsey-excitation) was employed. This technique allowed the resolution of spectroscopic structures with a full width at half maximum (FWHM) of below 20 kHz which were used to stabilize the laser frequency to the frequency of the intercombination line. (orig.)SIGLEAvailable from TIB Hannover: RA 3254(59) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Strukturbreitenmessung auf photolithographischen Masken und Wafern im Lichtmikroskop: Theorie, Einfluss der Polarisation des Lichtes und Abbildung von Strukturen im Bereich der Aufloesungsgrenze

Available from TIB Hannover: RA 3254(55) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Atominterferometrie in statischen elektrischen Feldern

Using a Borde atom-interferometer with a thermal atomic calcium beam, the shift of the interference structure in electric fields was studied. From the Stark shift of the intercombination line (4s4p "3P_1 - 4s"2 "1S_0) for the #pi# and the #sigma# transition the scalar and sensor polarizability of the 4s4p "3P_1 state were calculated. The measured Aharonov-Casher effect is by a factor of 10"3 smaller than the Stark effect and its measured value is close to the theoretically derived value. It is proposed to use the Borde atom interferometer for an optical frequency standard of high stability. (WEN)Available from TIB Hannover: RA 3254(48) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Vierwellen-Mischung in Laserdioden

Available from TIB Hannover: RA 3254(43) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Realisierung des Lorenz-Modells in Fir-Lasern

SIGLEAvailable from TIB Hannover: RA 3254(30) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Ein optisches Frequenznormal mit kalten und ultrakalten Atomen

The work presented here was concerned with the development and characterization of an optical frequency standard based on laser-cooled "4"0Ca atoms. For the realization of such a standard the frequency of a laser is stabilized to the narrow line of the clock transition of calcium at 657 nm. A frequency standard with cold Ca atoms at a temperature of 3 mK has been realized within the scope of the work. Furthermore, first experimental investigations regarding the application of ultracold atoms with a temperature of below 10 #mu#K have been performed. These investigations aimed at the improvement of stability as well as uncertainty of the Ca frequency standard. In the first part of the work, a new trap-apparatus was developed and used to investigate systematic errors with a relative uncertainty of 1 x 10"-"1"4. In the second part of the work, first atom interferometric investigations using ultracold atoms (temperature #theta##approx#10 #mu#K) showed their potential in the Ca optical frequency standard. (orig.)SIGLEAvailable from TIB Hannover: RA 3254(66) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Optische Eigenschaften von Augenschutzgeraeten und Methoden fuer deren Bestimmung

Copy held by FIZ Karlsruhe; available from UB/TIB Hannover / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Interferometrie mit laserpraeparierten Kalziumatomen zur Realisierung eines Frequenznormals

By investigations of Ramsey resonances at laser cooled Ca atoms it is demonstrated that with cool atom beams frequency standards are available with instabilities about 10 "-"1"4 ( "s"/ t_M) "1"/"2 and uncertainties #partial deriv##nu#/#nu# #approx# 10 "-"1"4 . The uncertainty can be reduced to < 10 "-"1"5 using pulsed excitements and laser trapped atoms. The frequency standard can be further improved by back-pumping of the "1D_2 state population via 5"1P_1 state into the cooling cycle and using the intercombination line for the cooling process. (WEN)SIGLEAvailable from TIB Hannover: RA 3254(40) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Ein optisches Frequenznormal auf der Basis lasergekuehlter Calciumatome

SIGLEAvailable from TIB Hannover: RA 3254(58) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman