Speaker
Ms
Elham Salehi
(Department of Physics, Amirkabir University of Technology)
Description
In recent years, theoretical and experimental studies have been shown that a relativistic electron in helical undulator emits an optical vortex which carries orbital angular momentum. In another word, the photon beam is the optical vortex, which has helical phase front.
In order to investigate the optical properties of optical vortex beams from undulators, Fresnel and Fraunhofer diffraction experiments are in progress at BL1U of UVSOR-III. There, optical vortex beam in the visible range can be produced as the second harmonics of the APPLE-II undulator in the helical mode and can be extracted without any optical components other than the quartz window. The diffraction experiments can be done in the air and a UV CCD Camera can be used as the detector. Therefore, the experiments are much easier as comparing with those at a higher energy machine. The low emittance of the UVSOR-III storage ring is also advantageous because the electron beam is almost in the diffraction limit in the UV range, otherwise the diffraction pattern may be smeared out.
In this presentation, we will show numerical simulation results on Fresnel and Fraunhofer diffraction of vortex beam by a knife edge and the double slits. They are compared with the latest experimental results from BL1U at UVSOR-III.
Author
Dr
Najmeh Sadat Mirian
(UVSOR- IMS)
Co-author
Ms
Elham Salehi
(Department of Physics, Amirkabir University of Technology)
