Open AccessDevelopment of a Tunable UV Laser System Synchronizing Precisely with Synchrotron Radiation Pulses from UVSOR
Author(s) -
Mizutani M.,
Tokeshi M.,
Hiraya A.,
Mitsuke K.
Publication year - 1997
Publication title -
journal of synchrotron radiation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.172
H-Index - 99
ISSN - 1600-5775
DOI - 10.1107/s0909049596013520
Subject(s) - synchrotron radiation , undulator , laser , monochromator , optics , synchrotron , photoionization , storage ring , photomultiplier , physics , materials science , atomic physics , ionization , wavelength , beam (structure) , ion , quantum mechanics , detector
A mode‐locked Ti:sapphire laser is made to oscillate at the frequency of the UVSOR storage ring, 90.115 MHz, in a multi‐bunch operation mode. The third harmonic of the laser is available in the wavelength range 243–280 nm. Synchrotron radiation from an undulator is monochromated by a grazing‐incidence monochromator and introduced coaxially with the laser. The temporal profile of the photon pulses is monitored in situ by a luminescing substance/photomultiplier combination. The delay timing between the laser and synchrotron radiation can be changed from 0 to 11 ns by adjusting an electronic module that provides phase‐locked loop stabilization of the laser pulse. The reliability and feasibility of this laser‐synchrotron radiation combination technique are demonstrated by applying pump‐probe experiments to two physical systems. The first system is photodissociation of iodomethane (CHA) with a laser photon, followed by photoionization of I and CH 3 fragments with synchrotron radiation. The second, two‐photon ionization of He atoms, is studied as the prototype of a time‐resolved experiment. The He + signal counts as a function of the laser–synchrotron radiation delay are found to be enhanced in a narrow time window, which can be interpreted in terms of a short lifetime of the resonant state, He*(1 s 2 p 1 P ), produced by primary synchrotron radiation excitation.