J. Eur. Opt. Society-Rapid Publ. 22, 7( 2026) 77
which produced two distinct pulses at a repetition rate of 1.612 kHz. Upon increasing the pump energy density to 50 J / cm 2, the system generated up to 22 pulses per burst at intra-burst repetition rate( f rep) of7.142kHz. Forthe longest cavity length studied( 465 mm), a higher threshold of 40 J / cm 2 was observed, with five pulses produced at 1.922 kHz at threshold and 17 pulses at 6.25 kHz when pumped at 50 J / cm 2.
Moreover, the temporal dynamics of dual pulse train generation in the passive Q-switched Nd: YAG laser were characterized, with a measured inter-train interval of 13.12 ms and individual train durations of approximately 250 ls. The pulse width within each train was found to be 45 ns, featuring a peak amplitude of 56 mV.
Finally, green light generation at 532 nm was successfully achieved through intracavity second-harmonic generation employing a KTP nonlinear crystal within the passive Q-switched laser cavity. The optimized frequency-doubled output exhibited pulse durations on the order of 6 ns, peak voltages reaching 65.2 mV, an intra-burst repetition rate( f rep) of 3.846 kHz, and a pulse period of 6 ns, reflecting efficient coherent nonlinear conversion in the KTP crystal.
Funding
This research was supported by Shahid Chamran University of Ahvaz, Iran under the grant number SCU. SP1401.259.
Conflicts of interest
Theauthorsdeclare thattherearenoconflicts of interest related to this work.
Data availability statement
The data that support the findings of this study are available from the corresponding author upon reasonable request.
Author contribution statement
Hossein Albaji: Experimentation, Data Curation, Writing – Original Draft.
Mohammad Sabaeian: Project Administration, Funding Acquisition, Methodology, Supervision, Conceptualization.
Hajar Alirezaei: Co-supervision, Experimentation, Writing – Review & Editing.
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