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

Abstract

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 μs. The decrease in ΔT gi with a change in |t i| from 90 to 10 μs 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 μs, 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.