用飞秒锁模激光测量光的频率

Measurement of laser frequencies with femlosecond mode-locked lasers

介绍了2005年诺贝尔物理学奖的获奖工作-用锁模飞秒激光光梳去测量光的频率。飞秒激光光梳技术大大简化了光频的测量。锁模飞秒激光通过光子晶体光纤时,由于自相位调制,在可见光和近红外区能够产生上百万等间隔的梳状频率,其频率间隔等于锁模脉冲的重复率。利用光频梳和倍频技术,把对光频的测量变为对射频的测量,这样就能够很容易地测出光的频率。使得光频测量精度和原子钟精度达到前所未有的高度,从而对物理学和计量学的发展有重要意义。

The work of the winners of the 2005 Nobel prize in physics is briefly reviewed, They measured the frequency of light with mode-locked laser comb. Femtosecond laser-frequency comb techniques are vastly simplifying the measurement. A single mode-locked femtosecond laser, its spectrum broadened by self-phase modulation in a photonic crystal fiber, can produce millions of sharp laser lines in a precise evenly spaced grid spanning much of the visible and near-infrared spectrum, the spacing of the frequency equal to the repetition of the modelocked pulse. They measured the radio frequency instead of optical frequency measurement with optical frequency comb and technology of octave-spanning. This is a significant step toward precision of optical frequency measurement and precision of atomic clock and a new brilliancy in physics and metrology.