Observation of birefringence in BBO crystals in the terahertz regime

Shigeki Saito, Elmer Estacio, Tomoharu Nakazato, Yusuke Furukawa, Toshihiko Shimizu, Nobuhiko Sarukura, Marilou Cadatal, Minh Hong Pham, Carlito Ponseca, Hiroshi Mizuseki, Yoshiyuki Kawazoe

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4 Citations (Scopus)


We present experimental results of birefringence in beta barium borate (β-BaB2O4 or BBO) crystals in the 0.2-1 terahertz (THz) frequency range. Standard polarized THz-transmission spectroscopy of a BBO slab cut under 90° was performed at different azimuthal orientations to determine the ordinary and extraordinary refractive indices. An average Δn/n value of 0.118 was calculated. Moreover, azimuthal angle-dependent absorption was observed at about 0.65 THz, in close agreement with calculations based on first principles. Our calculations showed the absorption feature was due to the low-frequency phonon modes of the [B3O6]3- rings. These results suggest that a BBO-based THz optical-parametric-oscillator design is feasible.

Original languageEnglish
Pages (from-to)895-898
Number of pages4
JournalJournal of Crystal Growth
Issue number3
Publication statusPublished - 2009 Jan 15


  • B1. Beta barium borate
  • B2. Birefringence
  • B3. Terahertz


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