OPTICAL PROPERTIES OF SINGLE-CRYSTAL PARATELLURITE (TEO2)
OPTICAL PROPERTIES OF SINGLE-CRYSTAL PARATELLURITE (TEO2)
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DOI：
10.1103/physrevb.4.3736
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发表时间：
1971-01-01
影响因子：
3.7
通讯作者：
UCHIDA, N
中科院分区：
文献类型：
--
作者：
UCHIDA, N
研究了基带边的吸收、折射率的色散特性、旋光率、相关的温度系数和光弹常数。在5×102 cm−-1范围内，吸收服从指数乌尔巴赫规则。在0.4~1.0μm范围内的折射率数据与振子位于9.2 4和4.70 eV的两项赛尔迈尔色散公式符合得很好。前者对可见光-红外区折射率的贡献大于后者。由Wemple和DiDomeico定义的色散能Edi=Fi Ei(其中Fi是振子强度因子，Ei是振子位置)被确定为9.24 eV跃迁的∼25 eV，与平均单振子的计算值一致。旋转力的色散也用两项Chandrasekhar公式解释，振子位置几乎等于从折射率得到的振荡器位置。光弹常数的色散测量表明，S 1应变引起的Fi和Ei的变化与S 3引起的Fi和Ei的变化之间存在很大的各向异性。折射率温度系数正值的主要贡献来自本征温度效应，而与热膨胀相关的光弹性效应的贡献是负的。在dN n dT和dρρdT的0.5~0.6μm之间观察到了反常行为，这可能是由于位于该波长区域的极弱的吸收峰所致。
Absorption at the fundamental band edge, the dispersion characteristics of the refractive indices, the optical rotatory power, associated temperature coefficients, and the photoelastic constants have been investigated. Absorption at the band edge has been found to obey the exponential Urbach rule up to 5× 10 2 cm− 1. Refractive-index data between 0.4 and 1.0 μm are excellently fitted to the two-term Sellmeier dispersion formula with oscillators located at 9.24 and 4.70 eV. The contribution of the former oscillator to the refractive index in the visible to infrared region is larger than that of the latter. The dispersion energy E di= F i E i (where F i is the oscillator strength factor and E i is the oscillator position) defined by Wemple and DiDomenico has been determined as∼ 25 eV for the transition at 9.24 eV, and is in agreement with the value derived for the average single oscillator. Dispersion of the rotatory power has been also explained by the two-term Chandrasekhar's formula with oscillator positions nearly equal to those found from the refractive indices. Dispersion measurements of the photoelastic constants reveal that a large anisotropy exists between the changes of F i and E i induced by the strain S 1 and those induced by S 3. The main contribution to the positive value of the temperature coefficient of the refractive indices comes from an intrinsic temperature effect, and the contribution of the photoelastic effect associated with the thermal expansion is negative. Anomalous behavior has been observed in dn n dT and d ρ ρ dT between 0.5 and 0.6 μm, and is probably attributable to extremely weak absorption peaks located in this wavelength region.