Frequency Stabilization Of A Laser Based On The Control Of Intermode Beat Note

Frequency-stabilized He-Ne lasers are widely used in interferometers as optical frequency (wavelength) standards, and used to calibrate optical wavelength meters due to its advantages such as stability, compactness and so on.In this work, a new technique for laser frequency stabilization has been introduced based on the relationship between laser frequency and intermode beat note. The intermode beat note was locked to the radio frequency standard to keep the cavity stable, as a result, the stabilization of He-Ne laser as well as the transform from radio frequency standard to optical frequency standard was realized.Theoretical analysis shows that the stability of the laser is identical with that of the intermode beat note; Experimentally, the intermode beat note was precisely locked to the radio frequency standard, as a result, laser frequency stabilization was achieved. The frequency comparison between two frequency-stabilized He-Ne lasers has been made. The result showed that the laser had a frequency stability of 5×10^-10 at 1 s of average time and 5 ×10^-11 in 100 s of average time. The laser frequency can be tuned precisely in the gain curve and it can be used as an optical frequency standard.