Carrier-envelope phase of ultrashort pulses

Abstract

Clearly, α is an important new parameter that can be explored in high-field experiments. Recent progress has shown that it can be "tamed" inside modelocked oscillators and preserved through amplification. Many of the first experiments in these directions have been described in this chapter. In addition to high-field experiments, control of the evolution of α has already had a big impact on optical frequency metrology, the measurement of absolute optical frequencies referenced directly to cesium. Prior to the introduction of mode-locked lasers, absolute optical frequency measurement required the use of complex phase-coherent frequency chains [69, 70]. Although the potential of mode-locked lasers was recognized more than 20 years ago [71], only with recent improvements in the technology have significant measurements with mode-locked lasers been made. The enormous simplification made possible by self-referencing and related techniques [2, 72, 73] has led to an explosion of measurements and significant improvement in precision. For a review of optical frequency metrology with mode-locked lasers, see Ref. [74]. Closely related to optical frequency metrology has been the development of optical atomic clocks based on mode-locked lasers. An optical atomic clock uses an optical frequency transition as its "oscillator" instead of a microwave transition used in traditional atomic clocks. This significantly reduces the uncertainty in a given averaging time because of large frequency. The first demonstration using a trapped single Hgb ion yielded stability results comparable to the best cesium clocks [75]. An optical clock has also been demonstrated using I2, which could lead to transportable clocks [76]. Remarkable advances have resulted from the synergy between precision optical techniques used in metrology and parallel progress in the generation of high-intensity pulses. Cross-fertilization between these seemingly disparate areas of research has resulted in truly remarkable strides over the past 5 years [77]. © Springer Science+Business Media, LLC 2008.