Coherent Control of Atoms and Molecules

Coherent Control of Atoms and Molecules byRandy Alan Bartels Co-Chairs: Henry C. Kapteyn & Margaret M. Murnane Whenever scienti c tools are signi cantly advanced, new discoveries soon follow.My thesis work relies on advances in ultrafast laser technology that allow precisecontrol over the shape of sub 20-fs laser pulses. This laser system enabled many newexperiments that yielded signi cant advances in attosecond science, atomic physics,extreme nonlinear optics, quantum chemistry, coherent control, molecular physics,ultrafast optical phase modulation, EUV coherent imagines, and EUV radiationsources.By using an automated learning control algorithm coupled to our deformablemirror pulse shaper, we have demonstrated the control of a process on an attosecondtime-scale for the rst time. We demonstrate the manipulation of the phase of anelectron wave packet, allowing us to tailor the EUV spectrum generated by high-orderharmonic generation. These optimal elds were discovered by a learning algorithmthat both found an unknown optimal solution, but also discovered an unknown phase-matching mechanism that occurs in the interaction of a single atom and light pulse.We control molecular vibrational and rotational coherences with the same learn-ing algorithm, demonstrating selective control in room temperature molecules atatmospheric pressures. Moreover, we demonstrate that modi cations to the algo-rithm can help automatically uncover the physics of the control mechanism found bythe learning algorithm.We also demonstrate a new pulse-compression technique using rotational phasemodulation, where optical pulses were compressed by an order of magnitude afterphase modulation by a molecular rotational coherence and subsequent propagation through a transparent window. This technique will enable e cient pulse compressionin the deep-UV.Finally, we measure the coherence of EUV light generated by high-harmonicupconversion of a femtosecond laser. In phase-matched hollowber geometry, theEUV light exhibits the highest inherent spatial coherence of any source in this regionof the spectrum. We use this source to demonstrate the coherent image with rsttable-top EUV radiation. Since this source exhibits full spatial coherence at veryshort wavelength, this light source represents has smallest inherent e ective source-size of any light source yet created. We also demonstrate that the spectrum ofan optical eld can be determined by measuring the interference of a double-slitpattern.