抄録
Development and recent progress of laser frquency control of gas, dye, and semiconductor lasers are reviewed. Narrowing of laser spectral width, stabilization of the center frequency and freqency tuning with high frequency stability are described. Ultrahigh frequency stabilties of 3×10-16 for a He-Ne laser and 10-14-10-15 for an Al Ga As laser has been realized. In these cases “phase stable” laser is more appropriate than “frequency stable” laser after J. L. Hall.
