Study On The Preparation And Non-linear Optical Properties Of Ge-Ga-S-KX(X=Cl,Br,I) Chalcohalide Glasses

Because of the nonlinear optical glasses with low cost,simple preparation,high chemical stability and so on,it will became the first-choice as materials for preparation of low costed optics devices,which make it hot topic by vast scientific researchers now. Chalcohalide glasses will show larger second- and third-order nonlinearity than those in oxide glasses,because they own higher refractive index and the structure change is also easily induced with applied field.The objective of this work is to investigate Ge-Ga-S-KX(X=Cl,Br,I) chalcohalide glasses to offer reference for its further applications.The third-order nonlinear optical property of the Ge-Ga-S-KX(X=Cl,Br,I) chalcohalide glasses was investigated by the femtosecond time-resolved optical Kerr effect(OKE) and Z-scan measurements.The Raman spectra of 0.56GeS₂-0.24Ga₂S₃-0.2KX(X=Cl,Br,I) glasses were also investigated to discuss the relationship between the structure and the nonlinear optical property.The third-order nonlinear optical property of the 0.56GeS₂-0.24Ga₂S₃-0.2KBr implanted by Ag⁺ was also performed by OKE and Z-scan measurements.Atomic force microscope(AFM) was also performed to observe the nano-particls in the glasses.Larger and ultrafast third-order optical nonlinearity was observed in the Ge-Ga-S-KX(X=Cl,Br,I) glasses.It was indicated that 0.56GeS₂-0.24Ga₂S₃-0.2KBr glass showed the fast response time with 300fs The introduction of different halogen atoms caused the difference in the structure of the glass by Raman measurements.The visible transmission spectra of the samples showed that the absorption edge of the sample implanted by 2×10¹⁷ ion/cm² red-shifted obviously because of surface plasma resonance introduced by Ag⁺ nano-particle.The third-orde nonlinear susceptibility increased with increasing the content of Ag⁺ dopant,but it decreased finally.The real and imaginary part of the third-order non-linear susceptibility was measured by Z-scan measurements.The nano-particle was observed obviously by AFM measurements when the dopant was more than 1×10¹⁷ions/cm² size on the surface of the glasses increased with increasing the dose for implanting.The enhancement of third-order non-linearity was due to the stronger surface plasma resonance induced by the nano-particles in the glasses.Second-harmonic generation was observed in the 0.56GeS₂-0.24Ga₂S₃-0.2KI chalcohalide glasses with the effective thermal poling process.The maximum of second-harmonic generation as great as 3.74 pm/V was obtained under the optimized poling condition with 5.2 kV,260℃and 120 minutes with Maker fringe measurements. The second-harmonic intensity increased with the increasing of poling voltage, temperature and time.The mechanism of second-harmonic generation in the glasses was also discussed by the alignment of dipoles.