Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Phase-stabilized ultrafast lasers signal new era in measurement and research



Tara M. Fortier, A Bartels, Scott A. Diddams


The development of short-pulsed lasers has progressed steadily over the past 30 years. In the search for better techniques and materials to generate shorter and shorter pulses, the 1990?s witnessed the arrival of Kerr-lens mode-locked Ti:sapphire lasers as the system of choice for many applications. With the broadest fractional gain bandwidth of any conventional lasing material, Ti:sapphire can support the oscillation of millions of coherently related frequencies. In a mode-locked laser, these laser cavity frequency modes have a fixed phase relationship and add together coherently such that the Fourier superposition results in a very strong amplitude modulation of the optical carrier-wave. With sufficiently broad gain bandwidth, this modulation is so strong that all the light waves add up constructively for only a few femtoseconds (10-15 s), resulting in ultrashort pulses that repeat at a periodic interval determined by the roundtrip travel time of the field inside the laser cavity (typically 1-20 ns). Since all of the energy in the light waves is concentrated in such a short time span, these light pulses possess significant peak power (~1 MW). In the research field of ultrafast phenomena, such a laser?s applications have traditionally been two-fold; one may either make use of the large peak power for non-linear optics, or take advantage of the fs resolution for time-domain spectroscopy.
Laser Focus World


optical frequency combs, optical frequency metrology, ultrafast lasers


Fortier, T. , Bartels, A. and Diddams, S. (2006), Phase-stabilized ultrafast lasers signal new era in measurement and research, Laser Focus World, [online], (Accessed July 19, 2024)


If you have any questions about this publication or are having problems accessing it, please contact

Created May 15, 2006, Updated February 17, 2017