Professor Gérard A. Mourou is the A. D. Moore Distinguished University Professor of Electrical Engineering and Computer Science and Applied Physics at the University of Michigan. He is the Director of the National Science Foundation Center for Ultrafast Optical Science.  He has been the recipient of the Wood Prize from the Optical Society of America, the Edgerton Prize from the SPIE, the Sarnoff Prize from the IEEE, and the 2004 IEEE/LEOS Quantum Electronics Award.  He is a fellow of the Optical Society of America and a fellow of the IEEE (Institute of Electrical and Electronics Engineers). He is a member of the American Physical Society and is a member of the National Academy of Engineering.

 

For thirty years, Professor Gérard Mourou has pioneered the field of Ultrafast Lasers and their applications in scientific, engineering and medical disciplines. Here are some of his accomplishments:

 

Creation of Ultrahigh-Intensity Fields: Focusing the world electrical grid’s power on a micrometer spot. With students D. Strickland, S. Williamson, P. Maine, and M. Pessot, he demonstrated the technique known as Chirped Pulse Amplification (CPA).  This technique has revolutionized the laser science field by making possible the amplification of ultrashort pulses to a level 10³–10⁵ higher in power than what was possible using conventional techniques.  Tabletop lasers could deliver pulses with terawatt peak power.  A terawatt is the power of the world’s electric grid.  This power can be focused over a spot size on the order of a few micrometers.  Extremely high intensities can then be achieved, in the range of 10¹⁸ W/cm², opening up a new regime in physics.  With these excessive intensities, we can create the highest electric field — 10¹² V/cm (a million times the breakdown field of most materials), the highest pressure — terabars (10¹² or a trillion times atmospheric pressure), and the highest temperatures — 10⁷ K (as hot as the center of the sun, 1000 times hotter than the surface of the sun).  The physical conditions that can be recreated are those that existed 1 millisecond after the “Big Bang”.

 

Opening the field of Relativistic Nonlinear Optics. The laser-matter interaction at these intensities has opened up the field of nonlinear optics, where the nonlinear interaction is due to the relativistic character of the electron motion. Harmonics, self-focusing effects have been demonstrated.

 

An attempt to bring “Big Science” back to the university. One revolutionary aspect of this science is that some of the experiments traditionally done on large-scale instruments can now be done with relatively compact and inexpensive CPA laser systems. In a sense, the CPA technology offers the possibility of bringing the science done on large instruments back to university laboratories. This technology has been adapted to large, existing lasers built for laser fusion and has enabled laser-matter interaction with a power 10³–10⁴ larger than previously possible. The impact of CPA in science can be appreciated in the Figure 1 (below, left).  One of the applications of the colossal intensities that can be obtained is the acceleration of electrons and protons (see Figure 2 below, right).

 

 

Femtosecond Precision Surgery. With student D. Du, J. Squier, and Drs. R. Kurtz and P. Lichter, he showed that a CPA system with the right energy level, pulse duration, and repetition rate could be used as a very accurate scalpel with no collateral damage (see Figure 3 below, left). His colleagues are using femtosecond lasers for ophthalmic surgery, photorefractive surgery, and glaucoma treatment. 

 

Ultrafast Electronics. With student J. Valdmanis, he applied ultrafast lasers for the characterization of ultrafast devices. They demonstrated the technique of electro-optic sampling, which has a few-hundred femtosecond resolution corresponding to terahertz bandwidth. This technique is considered the best way to characterize high-speed electronic devices and circuits (see Figure 4 below, right).

 

 

Generation of Terahertz Radiation. With student D. Blumenthal, he demonstrated the generation of single-cycle terahertz radiation from a semiconductor.  This technique has been improved by numerous groups and makes possible a new type of spectroscopy in the terahertz regime.

 

Picosecond High-Power Switching. Using laser-induced photoconductivity, he and student W. Knox showed that kilo-electron-volts could be switched with sub-picosecond precision. This technique is the cornerstone of synchronization of ultrafast instruments such as streak cameras. It is applied now in time-resolved x-ray diffraction with synchrotron radiation.

 

Picosecond Electron Diffraction. With student S. Williamson, he demonstrated that electron diffraction could be done on the 10-ps time scale. They used this technique to time-resolve phase transition. In aluminum, they studied the physics of melting.

 

Materials Science: Micromachining. His group was the first to observe the deterministic character of the damage threshold for femtosecond pulses. This characteristic must be seen in opposition to the stochastic character of damage threshold observed for long pulses. This property, combined with the reduced thermal diffusion, makes possible the ablation of materials with sub-micrometer precision. This characteristic special to femtosecond pulses led to the applications in micromachining, certainly the most important real-world applications of femtosecond lasers (see Figure 5 below).

 

 

Materials Science: Epitaxial deposition.  Using femtosecond lasers, members of CUOS led by P. Pronko have recently demonstrated the ability to deposit epitaxially thin films of oxides and semiconductors on a substrate.  Figure 6 (below) shows the individual atomic layers of tin-dioxide deposited on sapphire. Note the quality of the interface (indicated with arrows).

 

Materials Science: Isotope separation.  The strong magnetic and electric field produced by the interaction of intense femtosecond pulses with a solid target was used by the CUOS materials science group to demonstrate a new isotope separation technique. The technique works like a centrifuge of micrometer scale.