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Past Events
Joint Chemistry & Physics Departments Graduate Lectures: Interaction of Atoms and Molecules with Lasers
| Speaker: | Prof. Wing-Ki LIU |
| Affiliation: | Department of Physics, University of Waterloo, Canada |
| Date: | Part I: November 17 / 19, 2009 Part II: November 24 / 26, 2009 |
| Time: | 4:00-5:00 p.m. |
| Venue: | JG01, James Hsioung Lee Science Building / S324, Meng Wah Complex |
Part I: Coherent electronic and vibrational excitations of molecule
| Date | Time | Venue |
| Nov 17, 2009 | 4:00 - 5:00 p.m. | JG01, James Hsioung Lee Science Building |
| Nov 19, 2009 | 4:00 - 5:00 p.m. | S324, Meng Wah Complex |
The coherent interaction of lasers with an atom or a molecule (the system) will be discussed using a simple quantum mechanical 2-level model for the system and the laser will be described classically. The optical Bloch equations will be derived and interpreted classically. The experiment by Melinger, et al., J. Chem. Phys. 95 (1991) 2210, in which significant population from a lower rovibronic level of I2 was transferred to an upper level can be understood using this model as an example of adiabatic following. For multi-level systems, coherent adiabatic process will be discussed in terms of dressed states. Experiments on selective population of sublevels as well as excitation of ladder systems will then be described. A Raman chirped adiabatic rapid passage (RCAP) experiment carried out at Waterloo (J. Phys. B: At. Mol. Opt. Phys. 39 (2006) 3769) will be discussed. We used a femtosecond laser to ionize and Coulomb-explode the molecule undergoing RCAP to access the final vibrational excitation of the process, and understanding the ionization process leads to Part II of the lectures.
Part II: Introduction to attosecond science
| Date | Time | Venue |
| Nov 24, 2009 | 4:00 - 5:00 p.m. | JG01, James Hsioung Lee Science Building |
| Nov 26, 2009 | 4:00 - 5:00 p.m. | S324, Meng Wah Complex |
The effects of a high intensity ultrafast far-IR laser pulse on an atom -- above-threshold ionization (ATI) and high harmonic generation (HHG) -- will be addressed. The mathematical technique of saddle-point approximation to integrals will be reviewed, and then applied to the theories of ATI and HHG. The possibility of generating attosecond coherent XUV pulses will be explained, and recent experiments will be described.
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