FREQUENCY CHAIN TOWARDS THE CA INTERCOMBINATION LINE BASED ON LASER-DIODES - 1ST STEP

Stable, narrow linewidth operation of red and 1.3 mum free-running las er diodes with external gratings in non-Littrow geometry is demonstrat ed. The resonance of the saturated fluorescence of an atomic beam with a contrast of 25% and a linewidth of 400 +/- 50 kHz of the Ca interco mbination line 4(1)S0-4(3)P1 (lambda = 657 nm) is shown. A high-power (110 mW) single-mode external cavity laser diode at 1.3 mum is used fo r second-harmonic generation in a KTP crystal. The beat signal (signal to noise ratio about 25 dB) of 10 nW second-harmonic radiation at 1.3 mum and the radiation of a laser diode in the visible spectrum, as a step to realize a frequency chain, is observed.