Thursday, August 18, 2011

What is the highest harmonics number ever created up to date?

Sorry for the belated post but I felt the urge of writing about the wonderful talk On Thursday the planary session by professor Margaret Murnane:



NLO from 2 w to 5100 w in 50 years.



(It was original titled "Nonlinear Optics at the Timescale of the Electron – Bright

Coherent Attosecond-to-Zeptosecond KeV X-Rays". I like the new title much more.)



I alway enjoyed her talks. I noticed during her talk she used the word "beautiful" many times, which showed her strong passion toward her work.



Indeed, this year they sucessfully generated 6-cycle FWHM, 3.9 micro meter 20-Hz, multi-mJ pulses from a novel optical parametric chipred pulse amplifcation architecture, which has the higest pulse energy from a femtosecond mid-IR source to date. (Optics letters Vol. 36 page 2755 2011, published a few weeks before the NLO meeting).



With this laser, full phase matching of HHG in the KeV region of th spectrum (up to the 5031th order) is possible. (CLEO 2011 postdeadline and 2011 NLO papers).



She mentioned that 5th and 7th HHG was discovered by accident in 1987. I wonder what those people would think of her achievement of producing several thousands of harmonics today?



The broadest coherent supercontinuum they generated support transform limited 2.5 attoseocnd pulse duration, scalable to zeptosecond time scales (1 zs=10 to the minus 21 s).



Below is a picture of the laser-like x-ray beam which I found from the 2011 CLEO postdeadine paper:







By the end, she mentioned the exciting application of the X-ray as the ideal probes of the nanoworld. It can also be used for coherent lensless imaging.







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