Izdebski Marek, Ledzion Rafał, Węgrzynowski Szymon
Institute of Physics, Lodz University of Technology, Wólczańska 217/221, 93-005 Lodz, Poland.
Materials (Basel). 2024 Apr 17;17(8):1850. doi: 10.3390/ma17081850.
The electro-optical properties of methyl silicone oils with viscosities ranging from 10 to 10,000 cSt have been studied extensively to verify their suitability as immersion liquids. Immersion liquids are often used in nonlinear optics to protect hygroscopic crystals from moisture, reduce multiple reflections, and protect against electrical breakdown. However, the lack of experimental data makes it difficult to select an optimal liquid that does not exhibit a significant electro-optical Kerr effect in the fringing electric field around the electrodes on the crystal. Electro-optical measurements were performed using an improved dynamic polarimetric method, which compensates for the measurement errors caused by inaccurate positioning of the electro-optical modulator's operating point on its transmission characteristics. The values of the Kerr coefficient ranged from -8.83 × 10 to -6.79 × 10 m V for all oil samples, at temperatures from 25 to 80 °C and frequencies from 67 to 1017 Hz. These exceptionally low values, together with a low dielectric constant, very good transparency, and high chemical stability, make methyl silicone oils highly suitable as immersion liquids. The Kerr coefficient and other electro-optical coefficients increased with increasing temperature. This unusual result cannot be adequately explained by Buckingham's molecular theory of the Kerr effect.
为了验证甲基硅油作为浸没液体的适用性，人们对粘度范围为10至10,000厘沲的甲基硅油的电光特性进行了广泛研究。浸没液体常用于非线性光学领域，以保护吸湿性晶体免受湿气影响、减少多次反射并防止电击穿。然而，由于缺乏实验数据，很难选择一种在晶体电极周围的边缘电场中不会表现出显著电光克尔效应的最佳液体。电光测量采用了一种改进的动态偏振法，该方法可补偿因电光调制器工作点在其传输特性上定位不准确而导致的测量误差。在25至80°C的温度范围和67至1017 Hz的频率下，所有油样的克尔系数值在-8.83×10至-6.79×10 m V之间。这些极低的值，再加上低介电常数、非常好的透明度和高化学稳定性，使得甲基硅油非常适合作为浸没液体。克尔系数和其他电光系数随温度升高而增加。这个不寻常的结果无法用巴克ingham的克尔效应分子理论得到充分解释。
