Compact ultrastable laser system for spectroscopy of {sup 2}S{sub 1/2} → {sup 2}D{sub 3/2} quadrupole transition in {sup 171}Yb{sup +} ion

We report the results of studying a compact laser system designed for manipulating a quantum state of the optical qubit based on the {sup 2}S{sub 1/2} → {sup 2}D{sub 3/2} quadrupole transition in the {sup 171}Yb{sup +} ion at a wavelength of 435.5 nm. An emission power of the laser system reaches 500 μW at λ = 435.5 nm and the relative frequency instability of at most 3 × 10{sup −15} is achieved at averaging intervals from 0.5 to 50 s with a subtracted linear frequency drift. The compactness of the developed system makes it possible to employ it in transportable systems including optical clocks. (laser spectroscopy)