Last week one could admire an additional star over Ottobeuren, where we carried out basic experiments at the Volkssternwarte (public observatory). The aim was to increase the fluorescence of the laser guide star by up to 60% with the help of special tricks originally developed for laser cooling in quantum technology.
Two buses with TOPTICA employees were able to witness the spectacle live last Tuesday and Wednesday. A 55-watt laser beam in the beautiful night sky is quite impressive and produced many “Ahhs” and “Ooohs” as well as various great photos. The event was accompanied by an exciting lecture by Wilhelm and Frank, respectively, as well as a nice evening snack (sponsored by the Leibinger prize money) and a guided tour through the observatory. Even if the following sleep was very short – the excursion was worthwhile for everyone.
After the departure of our TOPTICA colleagues, we went back to the measurements the same night, because the actual reason for the undertaking is the tests with which we want to measure the influence of so-called “frequency chirping” on the brightness of the guide star. For this we modulated the laser frequency with a sawtooth function and a rate of about 1 MHz/µs. This is not too much of a problem for the seed laser, but in order for the frequency doubling to follow this fast detuning, a greater development effort had been required. The principle had been successfully tested in earlier measurement campaigns on La Palma, but only at low power levels below 20 W. This time we have almost three times the power available and are curious about the chirping effect.
Two weeks the airspace over Ottobeuren remained closed for our measurements during the nights, now it is important to bring the laser system back safely and analyse the results.
This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 848413
