Lasing dynamics of diode-pumped Yb – Er laser with a passive Q switch exposed to high-power external light

The temporal dynamics of diode-side-pumped Yb – Er laser, with a passive Co²⁺ : MgAl₂O₄ Q switch illuminated by a light beam (total fluence of 0.15 – 0.16 J cm^-2) from a semiconductor pulsed module, is investigated. It is shown that, using this external illumination, one can change the lasing onset delay and the time jitter ΔT_gi. The dependence of ΔT_gi on the interval between the instant of switching the illumination module on and the lasing peak position t_i has a minimum at |t_i| ≈ 10 ms. The decrease in ΔT_gi with a change in |t_i| from 90 to 10 ms indicates that instant of lasing peak occurrence for the Yb – Er laser is partially controlled by the pulse from the highly stable semiconductor module. If |t_i| < 10 ms, the enhanced luminescence fluence in the cavity of Yb – Er laser exceeds 0.16 J cm^-2; the light beam from the module does not affect much the lasing process in the ytterbium – erbium laser; and, as a consequence, the time jitter recovers the initial value.