Long-term carrier-envelope phase coherence achieved. (General Development).NIST (National Institute of Standards & Technology, Washington, DC, www.nist.gov) The standards-defining agency of the U.S. government, formerly the National Bureau of Standards. It is one of three agencies that fall under the Technology Administration (www.technology. researchers have reported a significant extension of the laser technology being developed for optical frequency metrology and optical atomic clocks. While frequency-domain stabilization had heretofore been the chief concern, there are additional applications--in coherent control coherent control n. The use of coherent radiation, such as that generated by a laser, to change the behavior of atomic, molecular, or electronic systems, often to alter the likelihood of a chemical reaction. , signal processing See DSP. , and high-field physics--that also depend on long-term stabilization of the light field in the time domain. Recent measurements have demonstrated coherence times exceeding 100 s--corresponding to over 10 x [10.sup.10] consecutive laser pulses--of the optical-frequency carrier wave with respect to its pulse modulation. This work is based on ultrashort ul·tra·short adj. 1. Of or relating to radio waves with a wavelength less than 10 meters (33 feet). 2. Of extremely short duration: an ultrashort flash. 3. (femtosecond scale) pulses generated by mode-locked lasers. Light pulses this fast consist of only a few "wiggles wiggles - [scientific computation] In solving partial differential equations by finite difference and similar methods, wiggles are sawtooth (up-down-up-down) oscillations at the shortest wavelength representable on the grid. " of the electromagnetic field electromagnetic field Property of space caused by the motion of an electric charge. A stationary charge produces an electric field in the surrounding space. If the charge is moving, a magnetic field is also produced. A changing magnetic field also produces an electric field. , so the timing of the light wave relative to its pulse envelope is physically significant. Indeed, a repetitive train of such pulses is most useful when this phase relationship is maintained--and therefore, reliable--for extended periods of time. Previous research had focused on frequency-stabilizing the Fourier-transform of this complex optical signal, which appears spectrally as a "comb" of regularly-spaced spectral lines. However, for the additional target applications, the carrier-envelope phase coherence is more important. The new time-domain stability was achieved by using improved feedback loops and actuators in the mode-locked laser. This work was reported in the Aug. 15 issue of Optics Letters. CONTACT: Steve Cundiff, (303) 492-7858; cundiff@jila.colorado.edu. |
|
||||||||||||||||
Printer friendly
Cite/link
Email
Feedback
Reader Opinion