Metasurface silicon-based optical devices are highly integrated and high-performance, meeting the requirements of photonics integrated circuits. We present a design method for metasurface silicon-based gradient index (GRIN) optical lens. With easy calculation, this method supports large-area GRIN elements design. The Luneburg lens and integrated coupler are shown as examples. Such devices show good performances in simulations. The simulations show that the Luneburg lens can focus light from all directions equally well. The optical 1-dB bandwidth of the integrated coupler is about 100 nm. Our method provides a convenient and feasible approach for designing silicon-based GRIN lenses.
The mutual optical intensity (MOI) is a four-dimensional coherence function and contains the full coherence information of the beam. The propagation of mutual optical intensity through a soft x-ray beamline is analyzed with a new developed model named MOI. The MOI model is based on statistical optics. The wavefront is separated into many elements and every element is assumed to has full coherence and constant complex amplitude, which is reasonable if the dimension of element is much smaller than the coherent length and beam spot size. The propagation of MOI for every element can be analytically solved with Fraunhofer or Fresnel approximations. The total MOI propagation through free space can be obtained by summing the contribution of all elements. Local stationary phase approximation is implemented to simulate MOI propagating through ideal mirrors and gratings. The MOI model provides not only intensity profile, but also wavefront and coherence information of the beam. These advantages make MOI model a useful tool for beamline design and optimization. The nano-ARPES beamline at SSRF is analyzed using the MOI model. A zone plate is used to focus the beam. The intensity profile and local coherence degree at the zone plate are acquired. The horizontal coherence is much worse than the vertical one. By cutting the horizontal beam with the exit slit the horizontal coherence can be improved but at the flux loss. The quantitative analysis on the coherence improvement and flux loss at different exit slit size are obtained with the MOI model.
We present a short review of our activities carried out in Tongji University (Shanghai, China) in the field of theory and technology of soft X-ray multilayer diffraction gratings. Diffraction gratings are widely used to study the structure and dynamics of a matter in laboratory and space by spectral analysis techniques. Combining multilayer and grating structures into a single unit allows to increase essentially both the spectral resolution and the efficiency of the diffraction optics. The unified analytical theory of soft X-ray diffraction from multilayer gratings operating in the single-order regime is briefly discussed. The single-order regime occurs when incident wave excites the only diffraction order and it is characterized by ultimately high diffraction efficiency tending to the reflectivity of conventional multilayer mirror. Our first experiments in fabrication of the blazed multilayer gratings by anisotropic etching of a silicon crystal with small roughness of the facet surfaces are described.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.