Ein transportables optisches Calcium-Frequenznormal

Abstract

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