Agour Mostafa, Fallorf Claas, Taleb Fatima, Castro-Camus Enrique, Koch Martin, Bergmann Ralf B
Opt Express. 2022 Feb 28;30(5):7068-7081. doi: 10.1364/OE.450708.
In this contribution, we demonstrate the first referenceless measurement of a THz wavefront by means of shear-interferometry. The technique makes use of a transmissive Ronchi phase grating to generate the shear. We fabricated the grating by mechanical machining of high-density polyethylene. At the camera plane, the +1 and -1 diffraction orders are coherently superimposed, generating an interferogram. We can adjust the shear by selecting the period of the grating and the focal length of the imaging system. We can also alter the direction of the shear by rotating the grating. A gradient-based iterative algorithm is used to reconstruct the wavefront from a set of shear interferograms. The results presented in this study demonstrate the first step towards wavefield sensing in the terahertz band without using a reference wave.
在本论文中，我们展示了通过剪切干涉术对太赫兹波前进行首次无参考测量。该技术利用透射式罗恩奇相位光栅来产生剪切。我们通过对高密度聚乙烯进行机械加工制造了该光栅。在相机平面上，+1和 -1衍射级相干叠加，产生干涉图。我们可以通过选择光栅周期和成像系统的焦距来调整剪切。我们还可以通过旋转光栅来改变剪切方向。基于梯度的迭代算法用于从一组剪切干涉图中重建波前。本研究给出的结果展示了在太赫兹波段不使用参考波进行波场传感的第一步。
