Period doubling and deterministic chaos in continuously pumped regenerative amplifiers

Abstract

Multi-energy and chaotic pulse energy output from a continuously pumped regenerative amplifier is observed for dumping rates around the inverse upper state lifetime of the gain medium. The relevant regimes of operation are analyzed numerically and experimentally in a diode-pumped Yb:glass regenerative amplifier. The boundaries between stable and unstable pulsing are identified and stability criteria in dependence on the amplifier gate length and pump power are discussed.

Study on laser characteristics of Ho:YLF regenerative amplifiers: Operation regimes, gain dynamics, and highly stable operation points

“…The first experimental hint that there is an inherently stable RT beyond the bifurcation instability, as illustrated in Fig. 1 at high RTs, was demonstrated in [3]. This was more precisely studied for an Nd:YVO 4 RA, showing bifurcation for a large range of RTs, prior to the start of further inherently stable RTs [5].…”

“…Initially, observed instabilities in the output pulses from an RA were attributed to inherent noise originating from the pump sources [1]. However, later, it was reported that exceeding the repetition rate beyond a certain threshold value can also be a potential cause for large energy fluctuations [2,3]. This phenomenon, called bifurcation (or multifurcation), can cause output pulses to fluctuate between two (or more) values, and is an effect of the gain dynamics in RAs for consecutive pump and amplification cycles [3].…”

“…However, later, it was reported that exceeding the repetition rate beyond a certain threshold value can also be a potential cause for large energy fluctuations [2,3]. This phenomenon, called bifurcation (or multifurcation), can cause output pulses to fluctuate between two (or more) values, and is an effect of the gain dynamics in RAs for consecutive pump and amplification cycles [3]. Figure 1 illustrates the output pulses of an RA that shows bifurcation as a function of the round trip (RT).…”

“…126 Page 2 of 17 published by Dörring et al [3] for a Yb:glass RA. The susceptibility of RAs to show unstable output pulses was connected to the repetition rate of the RAs and the excited state lifetime of the gain medium ( gain ).…”

“…The numerical models that have been reported and used for the simulation of RAs either focused on a rather qualitative understanding of pulse instability and the underlying gain dynamics [3,4], or on the reproduction of concrete laboratory measurements [11,14,15]. In the first case, rather simplistic mathematical expressions were used, neglecting for example an explicit dependence of the pump intensity on the gain build-up.…”