Frequency stabilization of an internal mirror HeNe laser at 543.5 nm to I2-Saturated absorptions

Compact digital system for an iodine-stabilized laser

A compact digital control system based on an all-programmable system-on-chip iodine-stabilized laser is presented for realization of the meter. The system is composed of ZYNQ7000, peripheral circuits, and human-computer interaction, which can operate independently. An nth-harmonic extraction algorithm with less resource consumption is used in this system. The digital system overcomes the problems of complex debugging, large volume, and manual locking. Additionally, customers can set up, calibrate, and upgrade the system by themselves. Its stability is similar to that of the current analog system, with long-term stability of up to 10^-13. The repeatability of the two lasers with the digital system is approximately 1.5×10^-11, and the absolute frequencies satisfy the international recommendation.

Frequency stabilization of a green He-Ne laser

A new process for stabilizing the frequency of commercially available 543-nm He-Ne lasers is described. The stabilization method is based on anomalous dispersion of the gain medium. A total of four green lasers have been stabilized-two at the National Institute of Standards and Technology and two at the Institute of Scientific Instruments of the Czech Academy of Sciences-making it possible to study frequency variations of the lasers relative to each other. We have also stabilized a 633-nm laser by the use of the same method used for 543 nm.