Ultrafast laser molecule interaction, control and imaging of molecules with femtosecond laser pulses

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The program will be built around the Coulomb explosion technique (Coulomb imaging) this method uses the intense field of a laser to remove many electrons from a molecule in rapid succession, the atomic ions which the molecule is reduced to then repel each other with Coulombs force and fly apart. We will use time and position sensitive detection to detect all of these fragment ions and reconstructing the geometry of the molecule.  In order to make the best representation of a molecule it is necessary to remove as many electrons from the molecule in the shortest time, therefore as part of the program we will continue to develop and seek out the shortest pulses possible, with the highest intensity available.  One very important application of Coulomb imaging is to study the changing geometry of a molecule during an excitation or dissociation. We will aim to image the changing shape of molecules during a non dissociating excitation for the first time.Closely related to the pursuit of the Coulomb imaging process is a study of the ionization and dissociation mechanisms in small molecules.  Here we will use the capabilities of our apparatus to make complete measurements of molecular disintegration, to try to distinguish different pathways in the ionization process, we will map the way ionization changes as the molecule breaks apart.Finally we will aim to control the vibrational state of a molecule using two laser pulses which have energies varying in time such that the difference in their energies is always equal to the energy needed to increase the vibrational level. This is known as Raman chirped adiabatic passage or RCAP.  This method might be able to transfer a high proportion of a molecules vibration population to a specific level.  We expect that we might be able to image these vibrating molecules with a Coulomb explosion method.  This last part of the project will take place at the Advanced Laser Light Source near Montreal.