Takanori Tanikawa

Status and Prospects of Coherent Light Source Developments at UVSOR‐II

We are developing coherent light sources at the UVSOR‐II electron storage ring. We have developed a resonator type free electron laser in the visible to the deep UV range, coherent harmonic generation source in VUV range and coherent synchrotron radiation source in the terahertz range. A new five year plan has been started from FY2008, where a new 4m straight section will be created by moving the beam injection point, a new optical klystron type undulator will be installed and dedicated beam‐lines will be constructed. Great advances on the coherent light source developments at the new straight section are expected.

Observation of Saturation Effect on Vacuum Ultraviolet Coherent Harmonic Generation at UVSOR-II

We have observed coherent harmonic generation in a deeply saturated regime. We measured the intensities of coherent harmonic (CH) up to the ninth harmonic of a Ti:sapphire laser in a wide range of peak laser powers. The CH intensities increase with the peak laser power and reach a maximum. The maximum occurs at a lower peak laser power for the higher CHs. Beyond this maximum, the CH intensity oscillates as the peak laser power is increased. A one-dimensional model explains these results in term of the formation of a double-peak structure in the longitudinal electron distribution.