Research Index / High-Field Technology
Faculty: John Nees - Roseanne Sension - Victor Yanovsky
Research Fellows: Vladimir Chvykov - Jinyuan Liu - Bing Shan
Graduate Students: Ahmasi Harris - Seung-Whan Bahk - Ned Saleh
Visiting Researcher: Pascal Rousseau
Past Researchers: Zenghu Chang - Dongfeng Liu - Haiwen Wang
CUOS has pioneered nonlinear optics in the single-period and single-wavelength regime. For the first time, we have demonstrated that relativistic intensities can be produced with a millijoule-level laser working with a few-optical-cycle pulse focused on a single wavelength. Deformable mirrors in conjunction with a f#1 paraboloid are used to focus the beam over the 1 micron, corresponding to the laser wavelength. The intensities produced by the mJ-kHz system are as large as the ones produced by much larger laser systems. These small, compact, high-repetition-rate lasers will make the field of relativistic optics accessible to a large number of kHz-mJ laser systems and will speed up the investigation of the new field of relativistic optics.
These very short pulses can produce a point source of x-rays of only a few-micron dimension. Because the plasma does not have time to expand during the pulse duration of 20 fs or less, the spot size can be as small as the laser spot size of 1 micron (in diameter). The x-source size that we have demonstrated is on the order of 5 microns and can be considered the smallest source of x-rays produced. This small spot size makes possible x-ray magnification. This type of source will be important for applications in high-resolution (millimeter) x-ray radiography.
The construction of our 150-TW laser is progressing. It is a Ti:Sapphire-based system delivering 4.5 Joules in 30 fs. Adaptive optics will be used to focus the light to a one-micron spot size to produce a laser intensity up to 1022W/cm2. The ultrahigh-intensity program includes a large component in contrast improvement.
In high-field atomic physics, higher harmonics can be obtained by using a femtosecond laser pulse at longer wavelengths (1500 nm or about twice the 800-nm wavelength of Ti:Sapphire). Using this approach, radiation with wavelengths in the sub-nanometer range can be obtained.
Copyright © Center for Ultrafast Optical Science, University of Michigan