Vladimir Zhukov, Alexander Rubenchik, Mikhail Fedoruk and Nadezhda Bulgakova, Novosibirsk State University Physics Department graduates, published an article in the well-known international Journal of the Optical Society of America. This article was included in the top 15 most read and downloaded articles on «Lasers and Laser Optics» in 2017 (6th place).
The article is devoted to mathematical modeling of the interaction of doughnut-shaped laser pulses with glasses in volumetric recording of photonic structures modes. Numerical calculations conducted by the NSU computing cluster showed that light pulses in the form of a ring (doughnut in the English-language literature) are much more efficiently absorbed by glass than standard Gaussian pulses with an ellipsoidal shape. Under equal conditions (energy, duration, angle focus), the maximum energy density of the laser radiation absorbed locally by the glass in the case of a doughnut pulse, is more than an order of magnitude higher than in a Gaussian pulse.
The results of this study shed light on a number of previously unexplained phenomena observed when femtosecond laser pulses were applied to transparent materials. For example, when effective fragmentation of metallic nanoparticles in a colloidal solution is achieved by replacing Gaussian pulses with doughnut pulses.
The NSU graduates discovered that the effect of ultra-strong localized absorption in volume can have applications in: materials processing technologies, studies of matter in extreme high temperature and ultrahigh pressure conditions, and the creation of new phase states of materials.
The article also shows that the interaction of ultrashort laser pulses with glass leads to a strong shift in the short-wavelength region of the radiation spectrum scattered by the plasma produced by the free electrons. This phenomenon is due to light passing through a plasma cloud with a rapidly changing density. The authors of the article believe that measuring the shift of the spectrum can be a reliable method for diagnosing the spatiotemporal dynamics of radiation absorption in experiments on the effect of ultrashort strongly focused laser pulses with matter.
V.P. Zhukov, A.M. Rubenchik, M.P. Fedoruk, N.M. Bulgakova, Interaction of donut-shaped laser pulses with glasses // JOSA B. 2017. Vol. 34. No 2. P. 463-471. (8 pages) [Journal of the Optical Society of America B, IF = 1.843]. https://doi.org/10.1364/JOSAB.34.000463