Densely-aligned void arrays of the length of hundreds of micrometers are fabricated in SrTiO3 crystal by tightly focusing multiple femtosecond (fs) pulses and fixing the focal point at a certain depth of SrTiO3 crystal without translation. The effect of the laser energy and the laser irradiation time as the well as entrance crystal plane on the induced structures is investigated. It is possible to control these factors to achieve the desirable void strings. This kind of self-fabrication method combined with the high linear refractive index of SrTiO3 (2.30 at 800 nm) largely extends the fabrication scope which is generally limited by the short working distance of the high numerical aperture (NA) objective lens in scanning fabrication mode. The possible formation mechanism is also discussed.
© 2007 Chinese Optics LettersPDF Article