波板(Waveplate)的應用在許多光電科技相關元件或產品上是不可或缺的重要組件，相較於其他固定式的波板薄膜，液晶波板能更便利地利用電控雙折射的特性改變其相位延遲，從而使光的偏振態產生改變。本論文主要研究寬頻液晶四分之一波板之光電特性以及其應用，主要利用理論計算與1D DIMOS軟體模擬慢軸和y軸夾角15°的液晶半波板與慢軸和y軸夾角75°的液晶四分之一波板的疊合，此組合可得一寬頻液晶四分之一波板，並驗證當入射光朝+z方向行進時，若為偏振方向與y軸夾角0°之線偏振光，其出射為圓偏振光，其中使用到偏振態的Stokes parameter及瓊斯矩陣運算，得到出射為高圓偏振度之圓偏振光之結果。而後續再結合90°扭轉向列型液晶旋轉前述之0°線偏振光之偏振方向至90°線偏振，此入射角的改變並不會影響出射穿透度及圓偏振度絕對值，僅僅改變出射圓偏振光之旋性。後續實驗結果也證實能以電控的形式控制液晶的相位延遲，進而得到組成寬頻液晶四分之一波板所需用的液晶半波板與液晶四分之一波板，並在寬頻液晶四分之一波板頻譜的量測中證實與模擬結果相同之高圓偏振度出射結果。在後續搭配90°扭轉向列型液晶實驗中也驗證了出射圓偏振光之旋性可以施加電壓的方式進行切換。;Waveplate is considered as an indispensable and important part for electronics. Compared with other waveplate thin films having a fixed phase retardation, the birefringence of liquid crystals (LCs) canbe electrically tuned to change the provided phase retardation. Therefore,the polarization of light passing through the LCs can be modulated.The main research topic reported in this thesis is the electro-optical properties and applications of LC broadband quarter waveplate. The theoretical calculation and 1D DIMOS software are used to simulate the superposition ofa LC half-waveplate with anazimuthalangle of15° made by its slow axisand y-axis and aLC quarter-waveplate with anazimuthal angle of 75° made by it slow axis and y-axis. A broadband quarter waveplate can be obtained by combining the waveplates with specific orientations of their slow axes. When the incident light is going toward +z direction and is linearly polarized with an angle of 0° with respect to y-axis, the outgoing light is circularly polarized. By analyzing Stokes parameters and Jones calculus, the outgoing lightcan be confirmed to be a circularly polarized light with a high degree of circular polarization (DOCP) value. Moreover, the broadband quarter waveplate combined with a 90° twisted nematic LC (90°-TNLC) cellcan electrically switchthe handedness of the outgoing circularly polarized light. Experimentally, it is also confirmed that the phase retardation provided by the LCs can be electrically controlled, and then the required half-waveplate and quarter-waveplate can be obtained to achievea broadband quarter waveplate. The measurement of the spectra confirms the same high DOCPvalue of the outgoing lightconsistent with the simulation results.It is also experimentally confirmed that the broadband quarter waveplate combined with a 90°-TNLC cellcan be used to switch the handedness of the outgoing circularly polarized light by applying a suitable voltage.
