Atomic Physics Research News

Itzik Ben-Itzhak

The J.R. Macdonald Laboratory has now firmly established AMO (Atomic, Molecular and Optical) ultrafast laser physics as its research theme. We hosted the 2^nd international conference on Attosecond Physics at the K-State Alumni center in July 2009. This successful meeting attracted more than 230 participants from  all over the world. Chii-Dong Lin and Zenghu Chang were co-chairs and led our group effort to organize this meeting with the help of many others in our department and K-State.

The Kansas Light Source (KLS) continues to serve as our main workhorse, now scheduled essentially 24 hours per day 7 days per week. This laser delivers 25 fs, 800 nm pulses with 3 mJ of energy at 1.5 kilohertz. The pulse can be shortened to 6 fs and the phase of the “carrier” of the laser relative to the envelope can be stabilized. In spite of the efficient use of the KLS beam time, lack of laser time has been the main limiting factor on our experimental program. To alleviate this problem, we have submitted a few proposals for a new and more advanced laser system. Recently, one of these proposals was funded by DOE at approximately 1.3 million dollars. We plan to have this new laser system operational before the end of 2010.

In the meantime, Zenghu Chang’s group has been working hard to keep up with the high demand for laser time, while continuously developing new capabilities such as isolated 140 attosecond laser pulses. A “Dazzler”, a device capable of generating “designer” pulses by cutting out or modifying user-chosen slices of the wavelength range of the pulse, has been used by Brett DePaola’s group and by Eric Wells, from Augustana College, to control reaction dynamics of atoms and molecules. We were excited to see Lew Cocke’s collaborative research on the interaction of light with simple molecules in the prestigious Science magazine (Vol. 322.p1081). Lew’s group is conducting similar cutting-edge experiments in our laboratory, in which a short train of attosecond pulses is generated and used to probe atoms and molecules. Igor Litvinyuk’s group uses intense laser pulses for time-resolved imaging of molecules – Coulomb explosion imaging with COLTRIMS or velocity map imaging (VMI). Vinod Kumarappan has begun aligning and orienting complex molecules in space and imaging them using VMI tomography. The new permanent-magnet ECR ion source has been used by Steve Lundeen, from Colorado State Univ., to study uranium ions, and by Itzik Ben-Itzhak’s group to study fragmentation of molecular ions by intense ultrashort laser pulses.

The JRML theory effort has paralleled our experimental work. For example, Chii-Dong Lin’s group developed a quantitative rescattering (QRS) theory that can be used for dynamic chemical imaging of a transient molecule or to characterize the laser pulse, Uwe Thumm’s group developed tools to predict the effects of strong laser fields on the electronic and nuclear dynamics in molecules and adsorbate-covered metal surfaces, and Brett Esry’s group studied the behavior of simple benchmark atoms and molecules in ultrashort, intense laser pulses and developed a general theory of multi-color control.

The groups of Kristan Corwin and Brian Washburn specialize in nonlinear optics and photonic crystal fibers (PCF) and their use for frequency metrology and laser physics. They have a Department of Defense (DOD) and an NSF funded project to develop frequency references in PCFs.  Using a phase stabilized fiber laser frequency comb, they measured to a 10 kHz accuracy an acetylene filled kagome PCF reference. They also have two DOD funded projects to develop a molecular gas laser inside a PCF.    

Changes of key JRML personnel continued with the hiring of Dr. Matthias Kling, from MPQ Garching, Germany, as a new faculty member in our department. Professor Igor Litvinyuk resigned his faculty position this summer and moved to Griffith Univ., Australia. We are especially proud to report that Zenghu Chang and Brett Esry were recently appointed Ernest K. and Lillian E. Chapin Professors in recognition of their contributions to JRML and the Physics department. We have also had many changes in junior lab personnel. As new postdocs, Kun Zhao from the Univ. of Nebraska-Lincoln has joined Zenghu Chang’s group, and Guillaume Laurent from the Univ. of Madrid, Spain, has joined Lew Cocke’s group. A couple of our postdocs moved to new jobs: Kamal Singh – Assistant Professor at the Indian Institute of Science Education and Research (IISER), Mohali, Chandigarh, India, Karl Tillman – Research Faculty at the Institute for Shock Physics in Spokane, Hiroki Mashiko – post-doc at Lawrence Berkeley National Lab (LBNL), Ximao Feng – post-doc at K-State chemistry, Jarlath McKenna – post-doc at Imperial College, London, UK, and Feng He was offered a professorship in Shanghai University starting in the summer of 2010. Three of our graduate students (advisor) received their PhD’s and moved to postdoc or industry positions: Fatima Anis (Esry) still at K-State, Irina Bocharova (Litvinyuk) now at LBNL, Ioannis Chatzakis (Richard/Ben-Itzhak) now at Iowa State Univ. In addition, a few of our graduate students completed their MSc’s: Nora G. Johnson (Ben-Itzhak), Jianjun Hua (Esry), Maia Magrakvelidze (Litvinyuk/Thumm), Maia and Nora are presently working toward a PhD. New graduate students in the JRML include: Qi Zhang (Chang), Chenchen Wang (Corwin), Bachana Lomsadze (DePaola), Dustin Ursrey and Shuo Zeng (Esry), Varun Makhija (Kumarappan), and Aihua Liu (Thumm).

We have had a long parade of excellent colloquium speakers in AMO this year. Roland Wester from Univ. of Freiburg, Germany, Matthias Kling from the Max Planck Institute for Quantum Optics, Germany, Markus Guehr from Stanford Univ., and Karen Sauer from George Mason Univ.. Outside speakers at our AMO seminar this year have included Gerhard Paulus from the Univ. of Jena, Germany, and Texas A&M Univ., Christian Madsen from the Univ. of Aarhus, Denmark, Claus Peter Schulz from the Max-Born Institut, Germany, Andre Staudte from NRC Canada, Lars Madsen from the Univ. of Aarhus, Denmark, Kathy-Anne Soderberg from the Univ. of Chicago, Christine Aikins from KSU Chemistry, Michal Bajcsy from Harvard, and Valer Tosa from the Natl. Inst. R&D, Romania.