Second-harmonic generation from Ge-Se-Sb chalcogenide films

Abdallah Slablab, Kalle Onni Aleksi Koskinen, Robert Czaplicki, M. Kailasnath, Indu Sebastian, C. Pradeep Chandran, Padmanabhan Radhakrishnan, Martti Olavi Kauranen

    Research output: Chapter in Book/Report/Conference proceedingConference contributionProfessional


    Chalcogenide glasses (ChG) are very promising for photonics because they have attrac- tive optical properties. The Ge-Sb-Se ChG films has been systematically studied with the aim of understanding the origin of their strong non-linear second-harmonic genera- tion (SHG) and the role for example of the multipolar contributions and the possible to quantitatively characterize the susceptibilities of bulk and surface of materials.
    In the most nonlinear optical materials, higher-multipole effects are negligible and the electric-dipole approximation adequately describes the process. However, for some ma- terials magnetic and electric-multipole effects can be shown to be non-negligible. Fur- thermore, the effects of different multipolar origin behave differently under different symmetry conditions. For example, the electric-dipole SHG is forbidden in the bulk of centrosymmetric materials but SHG due to electric-quadrupole effects is not. Conse- quently, understanding the behavior of multipole contributions is essential for proper analysis of certain materials and structural systems. The separation of dipole and higher- multipole effects is possible by SHG using two non-collinear fundamental beams. Very direct evidence of the higher-multipole contributions can be obtained by detecting s- polarized SGH light and modulating the polarization of one of the incident beams.
    The Ge-Se-Sb films were fabricated by the thermal evaporation technique. Such sam- ples were studied by two-beam SHG experiments using 70 ps pulses at 1064 nm and 1 kHz repetition rate. The transmitted s-polarized SHG signal was measured as a function of polarization of the incident fundamental beams. Our results show that the higher mul- tipole effects are present and contribute significantly to the second-harmonic response of Ge-Se-Sb films. Here, we will report a detailed analysis of the results.
    Original languageEnglish
    Title of host publicationProceedings of the 48th Annual Meeting of the Finnish Physical Society
    Number of pages1
    Publication statusPublished - 11 Mar 2014
    Publication typeD3 Professional conference proceedings


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