Measurement of isotope shifts in Sm I by using sub-doppler optogalvanic spectra with a single-frequency semiconductor master-oscillator power-amplifier laser

High-resolution optogalvanic spectroscopy near 670 nm was performed on atomic samarium generated in a hollow cathode discharge. For this experiment, a master-oscillator power-amplifier semiconductor diode laser source with a nominal output power of 500 mW was constructed. The isotope shifts were measured in sub-Doppler atomic spectra for two transitions: one at 667.151 nm (4f6 6s27F6 - 4f6 6s6p 9F7) and the other at 672.588 nm (4f6 6s2 7Fo - 4f6 6s6p 9F1). We showed that the field shifts estimated from the King plots contributed mainly to the observed isotope shifts for both transitions. Changes in the mean-square nuclear charge radii were derived from the field shifts, The output characteristics of a semiconductor power-amplifier with a laterally tapered gain region and seeded by a grating-tuned external-cavity diode laser are also reported