[1] Shen Y H. Sapphire fiber thermometer ranging from the room temperature to 1800 ℃[J]. Acta Optica Sinica, 20, 83-87(2000).

[2] Dai X, Li W L, Liu J et al. Research and application on sapphire fiber temperature monitoring system with wide spectrum[J]. Acta Optica Sinica, 33, s106006(2013).

[3] Yang S, Hu D, Wang A B. Point-by-point fabrication and characterization of sapphire fiber Bragg gratings[J]. Optics Letters, 42, 4219-4222(2017).

[4] Yang S, Homa D, Heyl H et al. Application of sapphire-fiber-Bragg-grating-based multi-point temperature sensor in boilers at a commercial power plant[J]. Sensors, 19, 3211(2019).

[5] Mills D A, Alexander D, Subhash G et al. Development of a sapphire optical pressure sensor for high-temperature applications[J]. Proceedings of SPIE, 9113, 91130H(2014).

[6] Nie M D, Zheng G, Zhang X X et al. Compensation for temperature drift in frequency-modulated continuous-wave interference fiber optic pressure sensor[J]. Laser & Optoelectronics Progress, 59, 0728002(2022).

[7] Li H J, Zhang Y. Transmission spectrum of multilayer AlGaN thin film on sapphire substrate[J]. Acta Optica Sinica, 40, 1931002(2020).

[8] Liao Y B, Pan A P, Lü M et al. An analytical method for measuring birefringence properties of single mode fiber[J]. Acta Optica Sinica, 4, 1062-1066(1984).

[9] Hao D Z, Wu F Q, Kong W J. Measurement of refractive index of crystals with interferometry[J]. Laser Technology, 27, 407-408(2003).

[10] Yan L P, Jiang J B, Lou Y T et al. Air refractive index measurement method based on laser single frequency interference and PTF sensor fusion[J]. Laser & Optoelectronics Progress, 60, 0512001(2022).

[11] Yuan C Y, Cao Y, Deng Y et al. Improving the measurement accuracy of refractive index of GaAs and sapphire crystal by laser feedback interferometry[J]. Infrared and Laser Engineering, 51, 304-310(2022).

[12] Liu X J, Liu L L, Fan K Z et al. Optical property parameter identification of turbid media based on multi-angle excited diffuse reflection light signal[J]. Chinese Journal of Lasers, 49, 1507205(2022).

[13] Cao X X, Li J B, Li J et al. Refractive index of r-cut sapphire under shock pressure range 5 to 65 GPa[J]. Journal of Applied Physics, 116, 093516(2014).

[14] Tang S H, Cao X X, He L et al. Effects of vacancy point defects and phase transitions on optical properties of shocked Al2O3[J]. Acta Physica Sinica, 65, 146201(2016).

[15] Cao X X, Lu T C, Zhou X M. Optical scattering extinction in shocked sapphire by theoretical calculation[J]. Journal of Atomic and Molecular Physics, 28, 485-493(2011).

[16] Yang D, Thomas M E, Tropf W J. Infrared refractive index of sapphire as a function of temperature[J]. Proceedings of SPIE, 3705, 60-69(1999).

[17] Lee G W, Jeon S, Park S N et al. Temperature and thickness dependence of IR optical properties of sapphire at moderate temperature[J]. International Journal of Thermophysics, 32, 1448-1456(2011).

[18] Thomas M E, Andersson S K, Sova R M et al. Frequency and temperature dependence of the refractive index of sapphire[J]. Infrared Physics & Technology, 39, 235-249(1998).

[19] Krishnan S, Weber J K R, Schiffman R A et al. Refractive index of liquid aluminum oxide at 0.6328 μm[J]. Journal of the American Ceramic Society, 74, 881-883(1991).

[20] Yan Y C. First principle study of electronic structures, mechanical properties and Debye temperature of α-Al2O3[J]. Materials Review, 32, 512-516(2018).

[21] Tohei T, Watanabe Y, Lee H S et al. First principles calculation of thermal expansion coefficients of pure and Cr doped α-alumina crystals[J]. Journal of Applied Physics, 120, 1528(2016).

[22] Tear G R, Chapman D J, Eakins D E et al. Birefringence measurements in single crystal sapphire and calcite shocked along the a axis[C], 1793, 060005(2017).

[23] Zhu S Y, Fang J X. Thermal effect of refractive index and the electron-phonon interaction[J]. Acta Optica Sinica, 7, 534-543(1987).

[24] Gao L H, Wang F C, Ma Z et al. Relationship of band structure and optical functions of Al2O3[J]. Rare Metal Materials and Engineering, 38, 773-776(2009).

[25] French R H. Electronic band structure of Al2O3, with comparison to Alon and AIN[J]. Journal of the American Ceramic Society, 73, 477-489(1990).