Inverse-source and inverse-diffraction problems in photonics

该项目涉及光子学中的逆散射和逆绕射问题，即根据散射场的测量性质或某些先验信息提供的信息来推断光源(逆源问题)或散射体(逆绕射问题)的特性的问题。这类反向散射问题属于衍射光学的前沿领域，具有重要的应用，如用于监测集成电路临界尺寸的散射测量。这项拟议的研究将解决在发展现代光子应用中的反向散射理论和方法方面遇到的挑战。特别是，我们考虑了亚波长表面浮雕光栅和衍射光学元件的逆衍射问题，以及一大类部分相干源的逆源问题，如LED和准分子激光器。这些逆问题的解是必不可少的。用于散射面的非侵入性测量和部分相干光与微纳光学相结合的精确建模。为了解决这两类逆问题，需要高精度的计量系统来精确测量各种衍射量，如光的强度、偏振和相干性。

The proposed project concerns inverse scattering and inverse diffraction problems in photonics,i.e., problems of inferring the characteristics of either a light source (the inverse-sourceproblem) or scatterer (the inverse-diffraction problem) based on information provided by eitherthe measured properties of the scattered field or some a priori information. This type ofinverse scattering problems lie in the frontier area of diffractive optics, which have importantapplications such as the scatterometry for monitoring the critical dimensions of integratedcircuits. The proposed research will address challenges encountered in the development ofinverse-scattering theory and methodology in modern photonic applications. In particular, weconsider the inverse-diffraction problem of subwavelength surface-relief gratings and diffractiveoptical elements as well as the inverse-source problem of a wide class of partially coherentsources such as LEDs and Excimer lasers. Solutions to these inverse problems are essentiale.g. for non-invasive measurement of scattering surfaces and accurate modeling of partiallycoherent light combined with micro- and nano-optics. For solving both types of inverse problems,high-precision metrology systems are needed to perform accurate measurement of variousdiffraction quantities such as intensity, polarization, and coherence of light.