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将时域有限差分(FDTD)方法用于非惯性坐标系下光子晶体理论研究,给出了非惯性坐标系下的差分方程和理想匹配层(PML)边界条件。设计了一个包含闭合环行腔和定向耦合器的光子晶体结构。定向耦合器的耦合长度为43a,这样的耦合长度既保证了闭合环行腔的高Q值,又保证了必要的频率分辨力。理论计算表明:光子晶体转动时,闭合环行腔里顺时针与逆时针方向传播的光有频差产生,此频差大小与光子晶体的转动角速度有关。
The finite difference time domain (FDTD) method is applied to the photonic crystal theory in non-inertial coordinate system, and the difference equations and ideal matching layer (PML) boundary conditions in non-inertial coordinate system are given. A photonic crystal structure consisting of a closed circular cavity and a directional coupler was designed. The coupling length of the directional coupler is 43a. This coupling length not only ensures the high Q value of the closed loop cavity, but also ensures the necessary frequency resolution. Theoretical calculations show that when the photonic crystal rotates, there is a frequency difference between light propagating clockwise and counterclockwise in the closed circular cavity, and the frequency difference is related to the rotational angular velocity of the photonic crystal.