ABSTRACT
We report on the frequency stabilization and on the measurement of the spectral density of frequency fluctuations (range 20 Hz to 20 kHz) and of the Allan variance (0.02 ms to 10(5) s) of a Nd:YAG laser for the VIRGO interferometric detector of gravitational waves. The short-term frequency fluctuations presented here compare favorably with those of other known oscillators. The Allan variance is better than 10(-14) for all measurement times below 0.1 s.
ABSTRACT
A method is given for the build up of simple off-axis beam expanders for Gaussian beams with low aberrations. In particular we show that it is possible to correct exactly the astigmatism in such a system. A realistic example is given.
ABSTRACT
A numerical model predicts the beam profile of solid-state variable-reflectivity resonators, taking into account diffraction, gain saturation, and stored energy depletion. An experimental analysis of propagation effects shows that the beam profile in the intermediate field is extremely sensitive to residual diffraction effects in the resonator.
ABSTRACT
We describe a frequency-stabilized diode-pumped Nd:YAG laser that is actively frequency stabilized relative to a reference Fabry-Perot cavity using the Pound-Drever technique. We describe the servo loop and the measurement of its noise and gain performance and demonstrate its ability to reduce the laser frequency noise close to the shotnoise limit of 12.5 mHz/ radicalHz. This corresponds to a linewidth of approximately 1 mHz, well below the Schawlow-Townes limit of 0.13 Hz that applies for a free-running laser.
ABSTRACT
Using an injection-locking technique, we obtain high-power single-frequency emission from a multimode argon-ion laser. Furthermore, a phase-control loop permits the stable, coherent summation of the beams from the two lasers.
