Research Of Dual-Color Fluorescence Phenomenon On Yb:YAG Laser Crystal

Yb³⁺ has only one basic state and one excited-state with the absence of excited-state absorption and upconversion.In addition,YAG has the good mechanism character and wide absorption band and it can be well coupled with pump source-InGaAs laser diodes,it also can be doped with a high concentration,so Yb:YAG is a promising crystal.The content of the paper include the following aspects:1.The advantages and development of all-solid-state lasers with the new Yb³⁺-doped crystals are introduced.The two coupled modes:end-pumped and side-pumped are presented.2.The optical characteristic and physical characteristic with the Yb:YAG crystals are introduced.The luminescence mechanism of the rare earth ions is introduced.3.The series of 460-494nm visible fluorescence of Yb:YAG crystal are excited by a semiconductor lnGaAs laser.The cause of visible fluorescence is analyzed.The mechanism of visible fluorescent is different to infrared fluorescent;it is cooperative absorption and emission of ion pairs.The emission intensities change with excitation power square.By increasing the density of ion pairs in the crystal. More strong visible fluorescence can obtained.4.The 485 nm blue laser of Yb:YAG with 6at.%doped by InGaAs LD end pumping is obtained.The cavity length of half-confocal plane concave cavity is 25mm.The output power is 472μW at pumping power 10W and beam angle of divergence is 9.5mrad.Wavelength of laser peak is 485.81nm and half width is 1.1nm.Another laser output positions are 471.90nm,494.63nm,460.23nm and 480.38nm.The mechanism of visible laser is analyzed.It is cooperative absorption and emission of ion pairs.