Hamburg 2009 – wissenschaftliches Programm

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Q: Fachverband Quantenoptik und Photonik

Q 55: Poster III

Q 55.3: Poster

Donnerstag, 5. März 2009, 16:30–19:00, VMP 8 Foyer

Tunable Frequency References for LISA – Piezo-Tuned Cavities — •Katharina Möhle, Klaus Döringshoff, Evgeny V. Kovalchuk, and Achim Peters — Humboldt Universität zu Berlin, Institut für Physik, AG Optische Metrologie, Hausvogteiplatz 5-7, 10117 Berlin

The interferometric read out of the space-borne gravitational wave detector LISA requires a high frequency stability of the employed Nd:YAG lasers, which should be achieved in three steps, including prestabilization to a Fabry-Perot cavity. The requirements for this prestabilization are a frequency stability of 30   Hz/√Hz from 1 mHz to 1 Hz, as well as a tunability of ±   15  MHz, in order to accommodate slow Doppler-shifts caused by yearly variation of the triangular satellite configuration. In addition there should be the capability to tune the frequency by more than one free spectral range from time to time.

Given the constraint of not using an optical modulator for offset locking, the first approach for a tunable prestabilization is to make the cavity itself tunable by adding a piezoelectric actuator. In this case one has to evaluate how the actuator affects the mechanical stability of the cavity, taking into account typical piezo material effects like hysteresis, creep and aging, but also other effects like thermal expansion and voltage noise. We present first results for the frequency stability obtained with different piezoelectric materials and discuss alternative approaches.