A laser system for the excitation of rubidium Rydberg states using second harmonic generation in a PPLN waveguide crystal

We report on a laser system at a wavelength of 495 nm which is suitable for the excitations of low lying Rydberg states of rubidium atoms. The system is based on frequency doubling of a seeded diode laser in a periodically poled waveguide crystal. We achieve an output power of up to 35 mW and prove the single-frequency performance by direct two photon laser spectroscopy of the rubidium 14D 5/2 and 14D 3/2 states. The measured fine structure splitting is consistent with quantum defect theory calculations.