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Q: Quantenoptik
Q 433: Poster: Laser – Grundlagen und Anwendungen
Q 433.11: Poster
Thursday, March 7, 2002, 16:30–18:30, Schloss
Modulation-free Rb-stabilised diode laser for interferometry — •Bernd Bodermann and Volker Burgarth — Bundesallee 100, 38116 Braunschweig
Frequency stabilised laser diodes are powerful, reliable light sources available at many wavelengths and capable of supplementing or substituting HeNe-lasers e.g. in high precision interferometrical length measuring systems.
For this purpose we developed compact frequency stabilised diode lasers emitting at 780 nm.
Conventional modulation techniques used for frequency stabilisation (e.g. 3f-technique)are expensive and the modulation contributes to the measuring uncertainty. However, until now no modulation-free frequency stabilisation method has achieved comparable long-time stability.
We investigated a new method using polarisation-optical differential detection of saturated Rb-absorption lines. A compact, low-cost and modulation-free stabilisation scheme based on this method has been realised. This system achieves a relative frequency reproducibility of δν/ν < 10−9.
A frequency comparison with a system using frequency modulation of the laser emission and standard 3f-detection for the frequency stabilisation to saturated Rb-lines was performed. We measured an Allan standard deviation of ∼ 3·10−11/√τ between both systems.