Dr. Yoshitaka Taira
Generation of gamma-ray vortices by nonlinear inverse Thomson scattering
After remarkable work conducted by L. Allen et al., which revealed that a Laguerre Gaussian (LG) laser mode carries orbital angular momentum (OAM) , research on optical vortices using visible wavelength lasers has thrived and resulted in successful applications in various research fields. Recently, generation methods of gamma-ray vortices have been theoretically investigated. We have proposed that the gamma-ray vortex in the MeV energy range can be generated by nonlinear inverse Thomson scattering using an intense laser . The gamma-ray vortex is thought to trigger new phenomena in Compton scattering and photonuclear reaction. Also, if the OAM of gamma-rays interacts with the OAM of quarks and gluons inside a proton, it may become a strong tool to measure the spin configuration of protons.
In this seminar, I will present the OAM characteristic and the spatial intensity distribution of the gamma-ray vortex generated by nonlinear inverse Thomson scattering as well as an experimental plan to be conducted at an accelerator facility. I also show some experimental results of a short pulse gamma-ray generated by inverse Thomson scattering.
 L. Allen, et al., “Orbital angular momentum of light and the transformation of Laguerre-Gaussian laser modes”, Phys. Rev. A, 45, 8185-8189, (1992).
 Y. Taira, T. Hayakawa, M. Katoh, “Gamma-ray vortices from nonlinear inverse Thomson scattering of circularly polarized light”, Scientific Reports, 7, 5018-1-9, (2017).