Introduction to the Issue on Ultrafast Science and Technology

IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS, VOL. 12, NO. 2, MARCH/APRIL 2006

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Introduction to the Issue on Ultrafast Science and Technology HIS is the ninth issue of an IEEE journal to focus on ultrafast science and technology—three special editions on this topic appeared in the IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS (JSTQE), preceded by five special issues published in the IEEE JOURNAL OF QUANTUM ELECTRONICS (JQE). Since the first “ultrafast-featured” edition in 1983, each of the additions to the series represented a snapshot of the state of the art in ultrafast laser science, technology, and applications and comprised a collection of papers of archival value. Over these 23 years, these issues of JQE and JSTQE have chronicled a remarkable evolution that the ultrafast field has undergone in its every area. At the time of the first special issue, femtosecond pulse generation and amplification still nearly exclusively relied on dye lasers, whereas now it is dominated by solid-state Ti:sapphire technology. Novel approaches based on parametric amplification and fiber laser technology are becoming increasingly critical for further progress toward shorter pulses, higher energies, and higher average powers. The femtosecond laser has matured from a capricious laboratory apparatus and an object of research into a robust versatile tool suitable for a variety of “real-world” applications, which range from applications in optical characterization, ranging, and data processing to micro- and nanomachining and fabrication, to biomedical imaging and surgery. The 2005 Nobel Prize in physics, awarded to Roy J. Glauber, John L. Hall, and Theodor W. H¨ansch, has highlighted the use of a broadband femtosecond laser in metrology as a source of an ultrastable optical frequency comb. In the past four years, the ultrashort frontier has moved from the femtosecond to the attosecond domain. Reliable generation of single-attosecond XUV pulses has become possible as the result of numerous improvements in the ultrafast technology, including higher peak intensities, better pulse compression techniques, and control over the pulse carrier-envelope phase. These technological developments have had ground-breaking scientific implications, enabling a shift from the studies of femtosecond structural dynamics in matter to real-time visualization of subfemtosecond electron dynamics. The purpose of this issue is to reflect on some recent developments that have occurred in ultrafast science and technology since the previous special issue in 2004 and to highlight the current trends. The collection of 17 exciting papers samples the state of the art across a broad range of ultrafast disciplines, ranging from novel ultrashort pulse generation techniques to novel

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applications of femtosecond pulses for radiofrequency signal processing. The opening set of papers describes on-going efforts in optical parametric chirped pulse amplification toward TW and PW peak powers and few- and single-cycle optical pulse generation. Further improvements in the pulse compression and amplification techniques have led to few-cycle optical pulse generation from conventional Ti:sapphire-based chirped pulse amplification laser systems. As a result of these advances, ultrashort amplified pulses now can be generated close to the Ti:sapphire gain-bandwidth-limited duration—or even beyond that—by employing external spectral broadening. The ability to achieve high intensities in few-cycle pulses with table-top laser systems has been instrumental in demonstrating new approaches to generating attosecond pulses. Continuing development of fiber-laserbased technology for chirped pulse amplification is leading toward unprecedented high-average powers from ultrashort pulse lasers and an extremely high practicality of such sources. A set of three papers examines progress in ultrashort-pulse semiconductor diode lasers, which offer the ultimate laser system compactness, efficiency, and robustness. One paper is devoted to novel material modification techniques that became available with femtosecond pulses and are continued to be further explored and perfected. Newly proposed techniques for ultrashort pulse characterization are discussed by two papers in the acknowledgment of the vital role that accurate pulse diagnostics has always played in improving femtosecond pulse sources and in their applications. Finally, the closing papers of this special issue give a different perception of the “ultrafast” science and technology—ultrahigh speed data analysis. These articles describe exciting applications of femtosecond pulses and optical carrier waves in general for rapid all-optical and RF–optical signal processing. The Guest Editors would like to express their sincere thanks to all of the authors who have submitted their papers and to all the reviewers whose valuable input has been instrumental in ensuring high quality and standards of the final selection of the papers. Finally, the editors are extremely grateful to Janet Reed and the great IEEE/LEOS team for their excellent administrative assistance, patience, and hard work in bringing this issue to fruition.

Digital Object Identifier 10.1109/JSTQE.2006.873825

1077-260X/$20.00 © 2006 IEEE

ALMANTAS GALVANAUSKAS, Guest Editor Electrical Engineering and Computer Science Department University of Michigan Ann Arbor, MI 48109-2122 USA

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IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS, VOL. 12, NO. 2, MARCH/APRIL 2006

MASAYUKI KAKEHATA, Guest Editor National Institute of Advanced Industrial Science and Technology (AIST) Tsukuba 305-8568, Japan

ANDRIUS BALTUSˇ KA, Guest Editor Max-Planck Institut f¨ur Quantenoptik D-85748 Garching, Germany

Almantas Galvanauskas was born in Vilnius, Lithuania, in 1963. He received the diploma in physics from Vilnius University, Vilnius, Lithuania, in 1986, and the Ph.D. degree in physics from the Royal Institute of Technology, Stockholm, Sweden, in 1992. From 1993 to 2001, he was with IMRA America Inc., Ann Arbor, MI, where he was leading research and development efforts on high-energy and high-power femtosecond fiber laser technology. Since 2002, he has been an Associate Professor in the Electrical Engineering and Computer Science Department, University of Michigan, Ann Arbor. His current research interests include nonlinear optics, fiber optics, ultrashort pulse, and high-intensity fiber lasers and their use for a variety of laser plasma applications. Dr. Galvanauskas is a member of the Optical Society of America.

Masayuki Kakehata was born in Iwate, Japan, in January 1966. He received the B.S., M.S., and Ph.D. degrees from Keio University, Yokohama, Japan, in 1988, 1990, and 1993, respectively, all in electrical engineering. He joined the Electrotechnical Laboratory (ETL) in 1993. In 2001, the laboratory was reorganized as National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan. He has worked on control of high-intensity femtosecond laser pulses. In particular, he has concentrated on generation of time-dependent polarization pulses, measurement of carrierenvelope phase, and development of carrier-envelope phase stabilized amplifier systems. His current research interests include control of optical field and its applications. Dr. Kakehata is a member of the Japan Society of Applied Physics, Laser Society of Japan, Institute of Electrical Engineers of Japan, and Optical Society of America (OSA).

Andrius Baltuˇska received the diploma in physics from Vilnius University, Vilnius, Lithuania, in 1993, and the Ph.D. degree in chemical physics from the University of Groningen, Groningen, The Netherlands, in 2000. From 2000 to 2002, he was a Research Associate with the group of Prof. T. Kobayashi at the University of Tokyo, Tokyo, Japan. Since 2002, he has been a Researcher with the group of Prof. F. Krausz at the Photonics Institute, Vienna University of Technology, Vienna, Austria, and the Max-Planck Institute f¨ur Quantenoptik, Garching, Germany. His current research interests include applications of intense fully controlled laser pulses in ultrafast spectroscopy and high-field physics. He plans on joining the Faculty of Electrical Engineering and Information Technology, Vienna University of Technology, in the spring of 2006. Dr. Baltuˇska is a member of the Optical Society of America. He was the recipient of the 2004 European Young Investigator Award from the European Science Foundation.