Interferometric detection enables the acquisition of the amplitude and phase of the optical field. By making use of the synthetic wavelength as a computational construct arising from digital processing of two off-axis digital holograms, it is possible to identify the shape of an object obscured by fog and further increase the imaging range due to the increased sensitivity in coherent detection. Experiments have been conducted inside a 27 m long fog tube filled with ultrasonically generated fog. We show the improved capabilities of synthetic phase imaging through fog and compare this technique with conventional active laser illumination imaging.

Transient dynamical–thermoelastic–optical system simulation is an important expansion of classical ray tracing through rigid, resting lenses because the operating performance of high-precision optical systems can be influenced by dynamical excitations or thermal gradients. In this paper an approach for an integrated optical system simulation using the coupling of elastic multibody system simulations, thermoelastic finite element analysis and gradient-index ray tracing is presented. Transient mechanical rigid body motions and elastic deformations, thermally induced refraction index changes, and thermal elastic deformations can be considered simultaneously in the ray tracing using the presented method. The calculation of the dynamical and thermal disturbances, the data transfer and coupling, and the gradient index ray tracing method are introduced. Finally, the approach is applied on a transient triplet lens optical system and some investigation results are shown.

We report on subwavelength reflective gratings for hyperspectral applications operating in a very large spectral band (340–1040 nm). Our study concerns a blazed-binary grating having a period of 30 μm and composed of 2D subwavelength structures with size from 120 nm to 350 nm. We demonstrate the manufacturing of the gratings on 3″ wafers by two lithography technologies (e-beam and nanoimprint) followed by classical dry etching process. Optical measurements show that the subwavelength grating approach enables a broadband efficiency, polarization behaviour and wavefront quality improvement with respect to the requirements for the next generation of spectro-imagers for Earth observation missions. An outlook towards spherical substrate based on nanoimprint lithography is also reported with the results of mixed features replication (holes and pillars in the range of 160–330 nm) on a 540 mm concave substrate which demonstrate uniformity and accuracy capabilities over 3″ surface.

研究了THz波段强降雨环境下电磁源的辐射特性。基于通用的麦克斯韦方程组和解析分析，提出了各向异性介质中的洛仑兹规范，得到了矢量势的非齐次波动方程及矢量势的精确表达式，并证明了它们的有效性。获得了各向异性介质中电偶极子的辐射场，将各向异性介质退化为各向同性时，得到的辐射场与已有资料中的辐射场一致。基于石膏晶体和强降雨介质的各向异性参数，对电偶极子的辐射特性进行了物理模拟和分析，结果发现：介质的各向异性对其中电磁源辐射有着显著的影响，强降雨中电磁源的辐射具有较弱的各向异性。