Noble metal containing photo-sensitive glasses have pulled the attention of many researchers for their photo-sensitivity for 3D micro-fabrication using femtosecond laser direct writing (FLDW). Moreover, ease of tailoring their optical properties relying on surface plasmonic behavior can be provided by changing metallic compositions and the size and concentration of metal nanoparticles. A combination of FLDW with metal containing glasses can be therefore an effective pathway to fabricate photonic 3D micro-devices such as micro-sensors.
It has been demonstrated by LPT that a formation of silver micro-structures using MHz regime femtosecond laser can exhibit a second order susceptibility in silver containing zinc phosphate glass. Figure 3 shows the laser-written silver micro-structure in zinc phosphate glass which is the basis of second order nonlinearity. A unique tube structure is formed due to the photo-dissociation by the tip of Gaussian beam shape.
Figure 3 shows a second harmonic intensity from a micro-structure probed by a laser at 1043nm. It proves that second order susceptibility is induced by a laser-written structure that is intrinsically prohibited in a centro-symmetric material such as glasses.