A theoretical model for the effect of optical path difference on coherent polarization beam combination of ultrashort laser pulses is established, and the effects of optical path difference and spectral width on coherent polarization beam combination efficiency of ultrashort laser pulses are studied. The corresponding control index is put forward, and this research has certain guiding significance for the design of coherent polarization beam combination system of ultrashort laser pulses.
Advanced an online low 1ω drive irradiance tuning technique of frequency conversion crystals of high power solid-state laser facility, which can acquire the best match angle of frequency conversion crystals through online low 1ω drive irradiance tuning curve test, and achieve fast and high precision angle correction to assure the frequency conversion crystals to achieve the highest energy conversion efficiency in shot experiments. Analyzed the possibility of online low 1ω drive irradiance tuning technique of frequency conversion crystals, researched the technical scheme of online low 1ω drive irradiance tuning of frequency conversion crystals, and applied this technique on SG facility, which achieved 60%~70% frequency conversion efficiency in high energy shots.
To assure that the frequency conversion crystals of SG facility are always being in the
best shot position, and have the highest energy conversion efficiency with various beam conducting
directions, we researched the precise tuning technique of frequency conversion crystals with the SG
facility. The on-line quick tuning method of target point detecting with preshot was used in precise
tuning of crystal match angle, and helped to correct the off-line match angle satisfactorily. With
crystal alignment technique and crystal accompany technique, the precise tuning of crystal match
angle can assure the crystals to maintain a stable high efficiency in a long experiment period.