The researchers were able to synchronize two independent femtosecond lasers and phase-lock the respective electric fields underneath the pulse envelopes to generate a single pulse of light that exhibits the properties of both lasers simultaneously.
“By combining the two lasers so precisely, we can create new shapes of light pulses that could not be created by either laser individually,” said lead author Robert Shelton, a professional research assistant at JILA, a joint program of the University of Colorado at Boulder and the National Institute of Standards and Technology, who completed the work in the lab of Jun Ye. A paper on the subject by Robert Shelton, Long-Sheng Ma, Henry Kapteyn, Margaret Murnane, John Hall and Jun Ye of JILA appears in the August 17 issue of the journal Science.
Ultrafast lasers, or femtosecond lasers, act as an ultrafast light switch similar to a strobe light, only the pulses of light from the laser are many orders of magnitude shorter than the strobe, Shelton said. Scientists use these flashes of laser light to freeze the motion of events that occur in atoms and molecules.
The interaction of coherent light with atoms and molecules, and the control of atoms and molecules have been prominent scientific themes in recent years, he said. Being able to combine the characteristics of two or more pulsed lasers working at different colors will give scientists a more flexible approach in their work with light and matter.
According to Hall, stabilized femtosecond laser pulses also have made possible an unanticipated route for connecting radio and optical frequency spectral regions.
The group�s work was accomplished by the successful merger of pulsed laser technology pioneered by researchers Murnane and Kapteyn with frequency domain laser control techniques developed by Hall and Ye.