Atomic Physics Research News

Itzik Ben-Itzhak

PictureThe J.R. Macdonald Laboratory continues at the forefront of AMO (Atomic, Molecular and Optical) ultrafast laser physics research and AMO in general. Hosting the 2nd international conference on Attosecond Physics at the K-State Alumni center in July 2009 has helped us establish this theme. Another big step in this will be the addition of PULSAR – a high repetition rate laser system that will complement our existing laser systems, provide ample beam time, and open new research opportunities for our experimental group. The PULSAR will occupy space that once housed the linear accelerator (LINAC) installed in JRML in the late 1980’s.

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 2 mJ of energy at 2.0 kilohertz. The pulse can be shortened to 6 fs and the phase of the “carrier” of the laser relative to the pulse “envelope” can be stabilized. In spite of the efficient use of KLS beam time, lack of laser time has been the main limiting factor on our experimental program. As mentioned above, we expect that the DOE funded PULSAR (~1.3 million dollar) laser system will alleviate this problem. We plan to have this new laser system operational before the fall of 2011.

In the meantime, Zenghu Chang’s group has kept up with the high demand for laser time, while continuously developing new capabilities such as isolated sub 100 attosecond (<10-16 s) laser pulses. Lew Cocke’s group is conducting cutting-edge attosecond physics experiments, in which a short train of attosecond pulses is generated and used to probe atoms and molecules. In addition, Lew continues his collaborative research on the interaction of light with simple molecules at the ALS as well as COLTRIMS and VMI studies of laser interaction with simple molecules locally, the latter in collaboration with Matthias Kling. Vinod Kumarappan continues to align and orient complex molecules in space and images them using VMI tomography or a recently developed optical method. 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. The ECR ion source has been used heavily by Steve Lundeen, from Colorado State Univ., to study uranium and thorium ions, and by Itzik Ben-Itzhak’s group to study fragmentation of molecular ions including unique molecular system, such as vibrationally cold CO2+, in intense ultrashort laser pulses.

The JRML theory effort has paralleled our experimental work. For example, Chii-Dong Lin’s group has employed their quantitative rescattering (QRS) theory to image a chemical reaction, Uwe Thumm’s group investigated the dissociation dynamics of molecules in ultrashort laser pulses and attosecond time resolved electron emission from atoms and metal surfaces by XUV pulses, and Brett Esry’s group studied the behavior of simple benchmark atoms and molecules in ultrashort, intense laser pulses. In addition, Brett’s research on cold collisions and Efimov physics has intensified since the approval of the MURI grant to the multi-university group he is part of.

We are especially proud to report that distinguished professor Chii-Dong Lin has received the 2010 Olin Petefish Award in Basic Science from the Higuchi Endowment Association. The Higuchi awards recognize accomplishments of researchers at Kansas Board of Regents institutions.

The groups of Kristan Corwin and Brian Washburn specialize in nonlinear optics and molecular spectroscopy in photonic crystal fibers (PCF) for metrology and laser physics. Recently, they demonstrated a new type of laser, in which molecular gases like acetylene and hydrogen cyanide, inside PCF, form a laser in the infrared (funded by the Department of Defense). In addition, their group continues to use phase-stabilized fiber lasers as frequency combs to perform precision spectroscopy on gases inside PCF, and to improve portable near-infrared frequency references.

Changes of key JRML personnel continued with the hiring of Dr. Carlos Trallero, from NRC Ottawa, Canada, as a new faculty member in our department. Professor Zenghu Chang resigned his faculty position this summer and moved to the University of Central Florida. His research group is undergoing a transition period that is projected to end by February 2012. We have also had many changes in junior lab personnel. As new postdocs, Baozhen Zhao from Osaka Univ., Japan, has joined Zenghu Chang’s group; Nicolais Guevara from Univ. of Florida, Christian Madsen from the Univ. of Arhus, Denmark, and Ed Meyer from JILA, have joined Brett Esry’s group. William Hageman from CREOL, Univ. of Central Florida, has joined Brian Washburn’s group. A couple of our postdocs moved to new jobs: Shouyuan Chen – a Research Assistant Professor at the Univ. of Nebraska, Lincoln, and Blake Laing – post-doc at Rowan Univ.  Six of our graduate students (advisor) received their PhD’s and moved to postdoc or industry positions: Steve Gilbertson and He Wang (Chang), post docs at Los Alamos and Lawrence Berkeley National Labs, respectively, Dipanwita Ray (Cocke), post doc at Argonne National Lab, Kevin Knabe (Corwin), post-doc at NIST, Boulder, CO, Yujun Wang (Esry), post doc at JILA, Boulder, CO, and Hyounguk Jang (DePaola), just graduated. New graduate students in the JRML include: Utuq Abulikemu and Ben Berry (Ben-Itzhak), Yan Cheng (Chang), Hui Li (Kling/Cocke), Geoffrey Jacobs (Thumm), Wes Erbsen (Trallero), May Ebbeni (Washburn).

We have had a long parade of excellent colloquium speakers in AMO this year. Oleg Kornilov from UC Berkeley, Brett Barwick from Cal Tech, Hans Wörner from NRC, Ottawa, Canada, Carlos Trallero from NRC, Ottawa, Canada, and Bernold Feuerstein from Max-Planck Inst. for Nuclear Physics, Heidelberg, Germany. Outside speakers at our AMO seminar this year have included Matthias Weidemüller from Heidelberg Univ., Germany, Ya Cheng from Shanghai Institute, China, Oded Heber from Weizmann Institute of Science, Israel, Bernold Feuerstein from MPI, Heidelberg, Germany, Cosmin Blaga from Ohio State Univ., Steve Lundeen from Colorado State Univ., Uri Lev from Weizmann Institute of Science, Israel, Martin Centurion from the Univ. of Nebraska, and Hiromasa Ito from RIKEN, Japan.