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Fig
. 21. The effect of increasing train pulses on the Intra-burst repetition rate( f rep) and period( a) cavity A,( b) cavity B,( c) cavity C, and( d) cavity D.
Fig. 22. Time between two successive burst.
Fig. 23. A group of burst pulses.
2. Intracavity linear polarization enforcement(> 99.9 % purity) via the fused-silica Brewster plate ensures optimal spatial and temporal overlap of ordinary and extraordinary waves in the type-II phase-matching process, thereby minimizing polarization-dependent phase-matching fluctuations that contribute significantly to output instability [ 36 ].
3. Utilizing high-quality 10 mm gray-tracking-resistant KTP enhances long-term stability and mitigates the green-induced degradation( gray-tracking) even at high peak intensities and intra-burst repetition rates, as demonstrated by the improved average 532 nm output power and reduced thermal effects compared to conventional KTP [ 37 ].
4. To minimize thermal‐dephasing and avoid phasematching drift which are known to degrade SHG stability in intracavity( KTP) the crystal temperature
Fig. 24. Single pulse produced in a pulse burst.
was actively stabilized using a compact thermoelectric cooler( TEC). This temperature control( on the order of a few tenths of a degree) helps prevent thermal