Research On The Passively Q-switched Lasers Based On Novel Nanoparticles

Passively Q-switched lasers have been a research hotspot due to their high efficiency,excellent beam quality,low cost,etc.As the switches of the Q-switching operating,their properties directly influence the quality of the pulsed laser.The preparation and application technology of the traditional saturable absorbers such as semiconductor saturable absorber mirrors,has been mature.But complicated fabrication,high cost and narrow absorption band restrict their further development.At the beginning of the twentieth century,graphene raised a study upsurge in optical field for their excellent optical properties.Graphene has the advantages of simple preparation,high damage threshold,wide absorption band and fast recovery time,which make it become the ideal material of the saturable absorber.As the influence of the graphene,people start to pay attention to the two-dimensional materials,and study the passively Q-switched lasers based on them.In this dissertation,we mainly study the passively Q-switched lasers based on gold nanotriangles,Au nanocages/SiO2 and rhenium disulfide.The main works are as follows:1.Study the passively Q-switched Nd:YAG ceramic lasers based on gold nanotriangles.By using gold nanotriangles as saturable absorbers,the pulses at 1064 nm and 1123 nm were obtained.For the laser with the wavelength of 1064 nm,we gained the pulsed laser with the average output power of 226 mW,repetition rates of 320 kHz and pulse width of 179 ns under the pump power of 4.1 W;while for the laser with the wavelength of 1123 nm,we gained the pulsed laser with the average output power of 172 mW,repetition rates of457 kHz and pulse width of 231 ns under the pump power of 7.01 W.2.Optimized the preparation of saturable absorber,prepared the gold nanotriangles in the form of poly vinyl alcohol film and used it in the Nd:GdVO4 laser to achieve pulse output.Under the output couplers with the transmittance of 4%,we gained the pulsed laser with the output power of 136.7 mW and pulse width of 237.5 ns under the pump power of 2.42 W.While under the output couplers with the transmittance of 10.8%.we gained the pulsed laser with the output power of 191.5 mW and pulse width of 268.6 ns under the pump power of 3.30 W.3.Study the passively Q-switched Nd:YVO4 lasers based on Au nanocages/SiO:.Utilized Au nanocages/SiO2 to realize the pulses output with the wavelength of 1064.3 nm.Under the output couplers with the transmittance of 40%.we gained the pulsed laser with the maximum output power of 140.6 mW.shortest pulse width of 154.2 ns and maximum repetition rates of 280 kHz under the pump power of 2.11 W.While under the output couplers with the transmittance of 10.8%,we gained the pulsed laser with the maximum output power of 150.2 mW.shortest pulse width of 222.0 ns and maximum repetition rates of 279.1 kHz under the pamp power of 2.42 W.It proved that Au nanocages/SiO2 has the saturable absorption properties.4.Study the passively Q-switched ytterbium-doped fiber laser based on Au nanocages/SiO2.Added Au nanocages/SiO2 into ytterbium-doped fiber laser and we obtained the stable pulse with the wavelength of 1060.5 nm.Under the pump power of 152 mW,we gained the pulsed laser with the maximum output power of 11.3 mW.shortest pulse width of 1.27?m and maximum repetition rates of 119.4 kHz.5.Study the passively Q-switched Nd:YAG laser based on rhenium disulfide.Under the pump power of 2.8 W,we obtained the pulsed laser with the central wavelength of 1064 nm.maximum output power of 209.2 mW.shortest pulse width of 312.3 ns and maximum repetition rates of 243.4 kHz.It proved that rhenium disulfide has the saturable absorption properties at 1?m.