Vol. 35, issue 10, article # 12

Ezhov D. M., Lubenko D. M., Mamrashev A. A., Andreev Yu. M. Temperature dependences of the refractive indices of a nonlinear LiB3O5 crystal in the THz range. // Optika Atmosfery i Okeana. 2022. V. 35. No. 10. P. 878–880. DOI: 10.15372/AOO20221012 [in Russian].
Copy the reference to clipboard


Using nonlinear LBO crystals of 30 × 30 ×​​​​​​​​​​​​​​ 10 mm3 in size, the spectral-temperature dependences of refractive indices in the long-wavelength part of the THz range 0.05–0.5 THz are obtained by means of terahertz time-domain spectroscopy under heating from 20 to 200 °C. Intersection of spectral dependences of the refractive index components nx and ny at ~ 84 °C is found. The results can be used for selection of types and phase-matching conditions for frequency conversion into long-wavelength part of the THz range, which is prospective for monitoring the gas composition of the atmosphere due to weak influence of the aerosol attenuation.


nonlinear crystal, lithium triborate, LiB3O5, THz range, temperature dependence, refractive index, difference frequency generation, birefringence


1. Naftaly M., Vieweg N., Deninger A. Industrial applications of Terahertz sensing: State of play // Sensors. 2019. V. 19, N 19. 35 p.
2. Marcus M., Pattan B. Millimeter wave propagation: Spectrum management implications // IEEE Microw. Mag. 2005. V. 6, N 2. P. 54–62.
3. Nikogosyan D.N. Lithium triborate (LBO) // Appl. Phys. A. 1994. V. 58, N 3. P. 181–90.
4. Andreev Yu.M., Kokh A.E., Kokh K.A., Lanskii G.V., Litvinenko K., Mamrashev A.A., Molloy J.F., Murdin B., Naftaly M., Nikolaev N.A., Svetlichnyi V.A. Observation of a different birefringence order at optical and THz frequencies in LBO crystal // Opt. Mater. 2017. V. 66. P. 94–7.
5. Waasem N., Fieberg S., Hauser J., Gomes G., Haertle D., Kühnemann F., Buse K. Photoacoustic absorption spectrometer for highly transparent dielectrics with parts-per-million sensitivity // Rev. Sci. Instrum. 2013. V. 84, N 2. 8 p.
6. Tu H., Hu Z., Zhao Y., Yue Y., Hou J., Fan F. Growth of large aperture LBO crystal applied in high power OPCPA schemes // J. Cryst. Growth. 2020. V. 546. P. 125728.
7. Yoshida H., Fujita H., Nakatsuka M., Yoshimura M., Sasaki T., Kamamura T., Yoshida K. Dependences of laser-induced bulk damage threshold and crack patterns in several nonlinear crystals on irradiation direction // Japan. J. Appl. Phys. 2006. V. 45, N 2A. P. 766–69.
8. Andreev Y.M., Naftaly M., Molloy J.F., Kokh A.E., Lanskii G.V., Svetlichnyi V.A., Losev V.F., Kononova N.G., Kokh K.A. LBO: Optical properties and potential for THz application // Laser Phys. Lett. 2015. V. 12, N 11. P. 115402.
9. Kononova N.G., Kokh A.E., Kokh K.A., Lanskii G.V., Losev V.F., Svetlichnyi V.A., Andreev Y.M. Down-Conversion of short-wavelength radiation in LBO crystal // Russ. Phys. J. 2016. V. 59, N 8. P. 1307–1315.
10. Tang Y., Cui Y., Dunn M.H. Thermal dependence of the principal refractive indices of lithium triborate // J. Opt. Soc. Am. B. 1995. V. 12, N 4. P. 638–643.
11. Grechin S.G., Zuev A.V., Kokh A.E., Moiseev N.V., Popov P.A., Sidorov A.A., Fokin A.S. Thermophysical parameters of the LBO crystal // Quan. Electron. 2010. V. 40, N 6. P. 509–512.
12. Mamrashev A.A., Nikolaev N.A., Kuznetsov S.A., Gelfand A.V. Broadband metal-grid polarizers on polymeric films for terahertz applications // AIP Conf. Proc. N 2300. 2020. P. 020083–020085.
13. Mamrashev A., Minakov F., Nikolaev N., Antsygin V. Terahertz time-domain polarimetry for principal optical axes of anisotropic crystals // Photonics. 2021. V. 8, N 6. P. 213.