The Resonance Ionization Laser Ion Source (RILIS) relies on a versatile, reliable and easy to use laser system to enable selective and efficient multi-step resonance photo-ionization of radioisotopes, for the majority of experiments at CERN-ISOLDE. A set of titanium sapphire (Ti:Sa) lasers complements the dye laser system of the ISOLDE RILIS installation , providing convenient access to the near infrared and blue parts of the optical spectrum.
Since their first use at ISOLDE , the Ti:Sa lasers have been under continuous development, extending their performance in terms of ease of use, spectral resolution, output power and beam quality. Intra-cavity frequency doubling has been achieved by introducing a non-linear BiBO crystal at the phase matching angle into the cavity. High efficiency and output power, together with a Gaussian profile of the generated second harmonic beam, have enabled us to easily saturate atomic transitions used for resonance ionization of elements of interest. A technique for scanning the frequency-doubled laser wavelength without additional beam steering has been developed. Subsequent frequency conversions to third and fourth harmonics have become more efficient due to the improved beam shape quality, leading to generation of high power UV laser light.
Here we report on the advanced performance of the RILIS Ti:Sa lasers as well as their applications in resonance ionization spectroscopy of stable and radioactive isotopes. An outlook for continued development activities, aiming at closing the existing gap in spectral range between dye and Ti:Sa lasers, will be presented.
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