Frequency stabilization of a diode laser to Doppler-free spectrum of molecular iodine at 633 nm

Abstract We report on frequency stabilization of a diode laser to the hyperfine components of the P(33) 6-3 and R(127) 11-5 transitions of molecular iodine at the He-Ne laser wavelength of 633 nm. Single frequency operation and wavelength control of the diode laser in a compact form is obtained by employing weak optical feedback from an integrated microlens. The diode laser driven by an ultra low noise current supply provides nearly shot noise limited detection. A relative frequency stability of 5×10 −12 is achieved at an integration time of 100 s. Harmonic distortion of the modulated output of the diode laser due to spurious optical feedback is considered to be the main effect limiting the day-to-day frequency reproducibility of 5×10 −11 .