The Ultra-fast Character Of The Alloyed Oxyorthosilicate Crystal

Efficient and reliable ultrafast lasers have many applications, iucluding inscientific research, industrial, medicine and communication. LD pumped solid-statelasers have become the central focus of recent researches, due to their simple structure,high efficiency, stable property. Yb crystals as laser gain medium in the ultrafast laserhave been occupied the ultrafast laser research important position. Yb-dopedLuYSiO₅is alloyed oxyorthosilicate crystal with high thermal conductivity and wideabsorb and emission crosssection. It is an ideal laser crystal in the realization of LDpumped ultralfast lasers. This dissertation mainly researched the ultra-fast character ofthe alloyed oxyorthosilicate crystal （Yb: LYSO）. Main contents can be summarized asfollows:1. We retrospected the development history and research status of ultrafastlasers, and introduce the characteristics of Yb³⁺-doped crystal and someimportant saturable absorber.2. We introduced the mechanism of mode-locking theory, including passivemode-locking, dual-wavelength mode-locking wave.3. We reported the diode-pumped Yb: LuYSiO₅laser mode locked bysingle walled carbon nanotube saturable absorber （SWCNT-SA） for thefirst time. Under the absorbed pump power of 12.83 W, continuous wave（cw） mode-locked pulses were generated with the maximum averageoutput power of 1.50 W. We obtained pulses as short as 5.2 ps around acenter wavelength of 1058.6 nm. The peak power and the single pulseenergy of the mode-locked laser were up to 2.9 kW and 15.0 nJ,respectively.4. Passively diode-pumped Yb: LuYSiO₅（Yb: LYSO） laser mode lockedby reflection-type single walled carbon nanotubes saturable absorber（RSWCNT-SA） is reported for the first time. Under the absorbed pumppower of 13.23 W, continuous wave （CW） mode-locked pulses were generated with the maximum average output power of 157 mW. Weobtained pulses as short as 4.0 ps around a center wavelength of 1038.3nm. The peak power and the single pulse energy of the mode-lockedlaser were 0.38 kW and 1.52 nJ, respectively.5. We report a passively dual-wavelength mode-locked Yb: LuYSiO₅（Yb:LYSO） laser with a double-wall carbon nanotube saturable absorber（DWCNT-SA） for the first time. Simultaneous mode locking at the1045.5 nm and 1059.0 nm were achieved and the dual-wavelength modelocked pulses had a pulse width of 8.0 ps. Ultrahigh repetition rateultrafast pulses with 750 fs pulse width and 3.66 THz repetition ratewere further formed. An output power of 1.27 W with a repetition rate of103.5 MHz was obtained using absorbed pump power of 12.83 W, with aslope efficiency of 13.0%.6. We introduced a dual-wavelength mode-locked Yb:LuYSiO₅（Yb: LYSO）laser with a graphene oxide saturable absorber .The center wavelength ofthe laser output is 1043.2 nm with pulses duration about 5.0 ps. Whenthe pump power reached up to 8.16 W, dual-wavelength mode lockingultrafast pulses operating at 1036.3 nm and 1043.5 nm simultaneouslywere detected. The maximum average output power was measured to be0.18 W. To the best of our knowledge, the dual-wavelength mode lockedlaser was first achieved by using graphene oxide saturable absorber.