High-sensitive spectroscopy of molecular iodine by means of power-stabilized light from a diode laser spectrometer

The hyperfine features of molecular iodine at 657 nm were observed with a high S/N ratio using a diode laser spectrometer whose intensity noise was reduced by feedback stabilization. The spectrometer consisted of a master/slave laser system, which enabled to stabilize the power independently of the frequency as well as to obtain stable single mode oscillation with moderate output power. The quantum limit of the sensitivity attainable by the power-stabilized laser was also calculated. The power-stabilized diode laser is available for the development of compact length standards having an output with very low intensity noise.