Femtosecond enhancement cavity with kilowatt average power

Zhang Jin^{1, 2}, Hua Lin-Qiang^{1, †}, Yu Shao-Gang^{1, 2}, Chen Zhong^{1, 2}, Liu Xiao-Jun^{1, ‡}

(a) Ideal enhancement can be reached when all the laser modes match the resonance modes of the fsEC. (b) Less enhancement appears when some of the laser modes match the resonance modes of the fsEC. (c) The effect of f₀ on the enhancement.