Patent ID: 7949018

Claim:
A mode-locked solid-state laser apparatus comprising: a resonator having an output mirror at one end of the resonator; a solid-state laser medium arranged in said resonator; and a saturable absorbing mirror; wherein said solid-state laser medium is arranged at a distance equal to or smaller than twice the Rayleigh range from said saturable absorbing mirror; said saturable absorbing mirror has a depth of absorbing modulation equal to or greater than 0.4%; said mode-locked solid-state laser apparatus is configured to impart a total intracavity linear dispersion D to light having a predetermined wavelength during a round trip of the light in said resonator, where the total intracavity linear dispersion D is smaller than zero and the absolute value |D|, having a relationship expressed by an equation,  D  = ( 1.76 ⁢ A eff , L 4 ⁢ π ⁢ ⁢ n 2 ⁢ l S ⁢ 1 0.315 ⁢ c ⁢ ⁢ Δλ P λ 0 ⁢ 1 E P ) - 1 with a light velocity c, a center wave length λ 0 of the light, a beam cross section A eff,L ( = πω L 2 ) of the light in the solid-state laser medium, a nonlinear refractive index n 2 , a crystal length 1 s of the solid-state laser medium, and pulse energy E P in the resonator, is within a range of minimum value 0 to maximum value which is calculated from pulse bandwidth Δλ P , in which ΔG(CW)=ΔR/2 and ΔG(DP)=ΔR/S are satisfied (where, ΔG(CW) is the gain advantage of the CW background with respect to the fundamental soliton pulse, ΔG(DP) is the gain advantage of the double pulse with respect to the fundamental soliton pulse in the resonator, and S is the saturation level of the saturable absorption mirror); and said output mirror is a negative-dispersion mirror which has a dielectric multilayer structure being formed on a substrate, including three or more multilayer mirrors and cavity layers, and having a thickness, the three or more multilayer mirrors are arranged at predetermined intervals across the thickness of the dielectric multilayer structure, each of the cavity layers is sandwiched between two of the three or more multilayer mirrors so as to cause resonance of the light between the two of the three or more multilayer mirrors, and the negative-dispersion mirror causes a mirror dispersion of −3000 fsec 2 to −600 fsec 2 and realizes a reflectance of 97% to 99.5%.