Characteristics Of All-solid-state Short Pulsed Nd:CNGS Lasers

Due to many advantages,such as simple constructions,high stability,long service time,high beam quality,high efficiency,small thermal effect,all-solid-state short pulsed lasers have an important application in industry,military,medical and other fields.The exploration and development of laser gain media have greatly promoted the development of all-solid-state short pulsed lasers.Up to now,the most widely used laser gain medium is active ions doped crystals.Among those crystals,neodymium ion(Nd3+)doped ones have the widest research and applications.Nd:YAG,Nd:YVO4,Nd:YLF,Nd:YAP as representatives of gain medium have been extensively researched and successfully used.However,in recent years,the demand and standard of the lasers in every field are getting higher and higher,so exploring new laser crystals and their characteristics has been the direction and goals of researchers.In 1998,Russian researchers reported and analyzed Ca3NbGa3Si2O14(CNGS)crystal for the first time,proving that CNGS is a kind of excellent piezoelectric crystals.Recently,considering its good thermal and optical properties,CNGS is expected to become a new type of matrix material for laser gain medium.Through a large number of research and experimental exploration,Guo Shiyi Professor group of our key laboratory has doping Nd3+ into CNGS and achieved a series of Nd:CNGS with different doping concentration.On this basis,our team evaluated the mechanical,thermal,spectral and multi-fuctional composite properties cooperating with Guo Professor team.The results present Nd:CNGS crystal have a potential for ultrafast laser.Thus,the main work of this dissertation is to analyze the performance of Nd:CNGS Q_switched lasers and mode-locked lasers based on the study of the optical properties and continue wave lasers of Nd:CNGS.The main content of this dissertation is listed as follows:?A brief introduction of Q-switched theory,the basic principle of acousto-optic(AO)Q-switched technology have been analyzed.Diode-pumped Q-switched Nd:CNGS lasers with AO modulator have been realized.By adjusting the AO driver,the laser operated at different repetition frequencies,and the corresponding average output power and pulse width have been measured under the different absorbed power.The corresponding peak power and pulse energy have been calculated.Pulses with duration of 13.8 ns were obtained,the corresponding single pulse energy and the peak power were determined to be 92.7 ?J and 6.3 kW.? Some basic parameters of Cr:YAG and V:YAG crystals have been simply introduced.The theoretical model of passively Q-switched with Cr:YAG as saturable absorber(SA)have been detailedly investigated.Based on the Cr:YAG and V:YAG crystals,passively Q switched Nd:CNGS lasers have been realized.At last,the maximum average output power was 0.59 W of y-cut Nd:CNGS crystal,pulses width duration of 22.89 ns at a repetition rate of 11.7 kHz were obtained,with single pulse energy of 92.7 ?J and peak power of 6.3 kW.? The character of black phosphorene and the preparation method of black phosphorene saturable absorption mirror(SAM)have been introduced.Using the prepared BP-SAM,passively Q switched Nd:CNGS laser at the wavelength of 1.3 ?m have been realized,and the output characters have been analyzed.The minimum pulses width duration was 22.89 ns were obtained with single pulse energy of 1.88 ?J and peak power of 6.3 kW? A simple analysis of mode-locked theory and solutions of avoiding the Q-switched mode locking in the passively mode locking laser have been explored.Ultrashort pulses of picosecond level with Nd:CNGS crystal have been detailedly investigated at the center wavelength of 1.0?m.Pulses with duration of 1.0 ps at a repetition rate of 49.2 MHz were obtained with the average output power was 115 mW.The corresponding single pulse energy and the peak power were determined to be 2.33 nJ and 2.23 kW,? A detailed analysis of the dispersion compensation of mode locking laser have been introduced.By Adding a chirped dispersion compensation prism in our picosecond cavity,the pulse width has been successfully compressed to 759 fs.The maximum average output power was 133mW,single pulse energy was 92.7 ?J and peak power was 6.3 kW.The results demonstrate the attractive potential for realizing femtosecond lasers using Nd:CNGS crystal.