Frequency Comb Laser

From Qwiki

Introduction

A Frequency Comb Laser (or Optical Frequency Comb) is essentially a well-stabilized Mode-Locked Laser. When the laser's spectrum can be made to span an optical octave, measurements (and hence stabilization) of the absolute laser frequency are possible. Thus, this device provides a very useful and practical tool whereby optical frequencies may be easily referenced to accurately known radio frequencies (Note that since the definition of the time unit "second" is based on an RF transition in Cesium, referencing an optical frequency to this standard is essentially the best one can hope for.) The frequency comb method thus provides a great advance relative to the Frequency-Chain methods which were previously employed for optical frequency measurement.

Basic Operation

Starting with a Mode-Locked Laser...

Additional Information

One half of the 2005 Nobel Prize in Physics was shared by John L. Hall and Theodore W. Hänsch largely for their contributions to the advancement of laser spectroscopy and specifically for their development of the Optical Frequency Comb technique.

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