Development of pulling interferometer with geometric phase modulation

在直接探测系外行星的过程中，零点干涉仪受到了广泛的关注。在第一个实验中，将一束线偏振光看作是两束正交线偏振光的合成，并利用一个偏振光对分解后的偏振分量进行相消干涉。然而，这种情况并不能完全模拟实际的拉动式干涉仪。在接下来的实验中，用马赫-曾德尔干涉仪产生两束独立的光束，并在每条臂上施加几何相位调制，从而进行拉干涉。几何相位或Pancharatnam相位在本质上与波长无关，相移值是可调的。这些几何相位特性对多元望远镜拉拔干涉仪非常有用。实验结果表明，在拉式干涉仪中实现任意弧度（小于2π）的相位分离调制是可行的，消光比达到0.8x10^4。

To directly detect extrasolar planets nulling interferometer gains wide attention, where extremely bright star-light is destructively interfered. In the first experiments, one linearly polarized light beam is considered as the synthesis of two orthogonal linearly polarized light and these decomposed polarization components are destructively interfered by use of a polarizes. However, this situation does not fully simulate a practical pulling interferometer. In the next experiments two separate beams are generated with a Mach-Zehnder interferometer and geometric phase modulation is exerted in each arm so as to perform pulling interference. Geometric phase or Pancharatnam phase is independent of wavelength in nature and the phase shift value is adjustable. These characteristics of geometric phase are very useful for pulling interferometer with multi-element telescopes.Experimental results reveal the feasibility of separate phase modulation of an arbitrary amount of radians (less than 2π) in pulling interferometer and the extinction ratio of 0.8x10^4 is achieved.