Anisotropy of two-photon absorption in gallium selenide at 1064nm

• Published in: Optics communications Vol. 261; no. 1; pp. 60 - 64
• Main Authors: Allakhverdiev, K.R., Baykara, T., Joosten, S., Günay, E., Kaya, A.A., Kulibekov (Gulubayov), A., Seilmeier, A., Salaev, E.Yu
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.05.2006
• ISSN: 0030-4018; 1873-0310
• DOI: 10.1016/j.optcom.2005.11.046

The Bridgman method is used to grow single crystals of ε-GaSe. The two-photon absorption (TPA) coefficient β was measured for especially un-doped crystals at room temperature for the ordinary o-ray (β⊥) and extraordinary e-ray (β∥) using single-wavelength excitation by a Nd:YVO4 laser at 1.064μm with a pulse duration of 10ps and a repetition rate of 81MHz. No large anisotropy was observed for the TPA coefficients between the two geometries. The TPA coefficients were found to be β⊥=1.07×10−9cm/W and β∥=1.88×10−9cm/W. It was found that doping slightly increases the TPA coefficient. The value of the TPA for crystals doped with 0.5at.% of Tl is β⊥=7.56×10−9cm/W.