Quantum control of ultrafast nonlinear optics

The research on femtosecond optical pulses in physics, chemistry, engineering and medicine to study ultrafast phenomena has become widespread in recent years, and has led to the establishment of whole disciplines such as soliton fiber communications, ultrafast high field physics, multi-photon microscopy and femtochemistry, among others. In particular, the development of laser systems capable of producing femtosecond laser pulses has opened the possibility to study quantum control schemes for chemical reactions in real time.

Our research

Coherent Stark nonlinear spectroscopy

We have recently developed a nonlinear spectroscopy tool based on the coherent control of transient optical four-wave mixing interactions in two and three-level systems. Quantum control of the four-wave mixing produced by two-color w-3w femtosecond laser pulses is accomplished by varying the relative phase between the two laser pulses. The phase-sensitivity of the spectral 5w anti-Stokes component is cancelled when the ac Stark shift produced by the w and 3w pulses is compensated. In a two-level system, we have found that the phase-sensitivity cancellation frequency is given by

                                            (w₁₂/w)²=5            PHASE-SENSITIVITY CANCELLATION

Ultrashort pulse control of spatial-dependent excitations

Coherent control of regions with spatial excitation of populations and coherence between two lower states in three-level L-type quantum systems mediated by the self-induced transparency (SIT) phenomenon is theoretically investigated with one- and two-color ultrashort pulses and with pulse sequences. The effects of different parameters characterizing the pulses and the medium on the location as well as the width of such excited regions have been studied numerically by means of the finite-difference time-domain (FDTD) method.

Coherent control of ultrafast dynamics in biosystems

We model transient-absorption and four-wave mixing experiments to study coherent control of ultrafast dynamics in complex molecular systems. In particular, we study quantum control in Carotenoids and in Nile Blue molecules with multipulses (http://www.uni-marburg.de/fb15/ag-motzkus/research/wavepackets).

People

Carles Serrat
Yurii Loiko

Collaborations

Quantum Optics, Universitat Autònoma de Barcelona
AG Motzkus, Philipps Universität Marburg, Germany

Selected publications

Carles Serrat, Coherent control of ultrafast optical four-wave mixing with two-color ω-3ω laser pulses, Phys. Rev. A 72, 023808 (2005)
Carles Serrat, ac Stark-mediated quantum control with femtosecond two-color laser pulses, Phys. Rev. A 72, 051803(R) (2005)
Yurii Loiko and Carles Serrat, Coherent and phase-sensitive phenomena of ultrashort laser pulses propagating in three-level L-type systems studied with the finite-difference time-domain method, Phys. Rev. A 73, 063809 (2006)
C. Serrat, Yu. Loiko, R. de la Cruz, and J. M. Cela, Coherent Stark nonlinear spectroscopy with chirped pulses, Phys. Rev. A (in press)
Yu. Loiko, C. Serrat, R. Vilaseca, V. Ahufinger, J. Mompart, and R. Corbalán, Ultrashort pulse control of spatial-dependent excitations in a three-level system, Phys. Rev. A (in press)