Lei Zheng

• Doctor of Engineering
• Researcher at Leibniz Universität Hannover

Due to their advantages of compact geometries and lightweight, diffractive optical elements (DOEs) are attractive in various applications such as sensing, imaging and holographic display. When designing DOEs based on algorithms, a diffraction model is required to trace the diffracted light propagation and to predict the performance. To have more pr...

In this work, we report on the application of the polarization modulated spectroscopic ellipsometry-based surface plasmon resonance method for sensitive detection of microorganisms in Kretschmann configuration. So far, rotating analyzer and single wavelength polarization modulation methods have widely been investigated for phase sensitive surface p...

Low-dimensional van der Waals (vdW) three-dimensional (3D) topological insulators (TIs) have been overlooked, regarding their electromechanical properties. In this study, we experimentally investigate the electromechanical coupling of low-dimensional 3D TIs with a centrosymmetric crystal structure, where a binary compound, bismuth selenide (Bi2Se3)...

An easily fabricated gas sensor based on planar polymer optical waveguides with an integrated zeolite imidazole framework‐8 (ZIF‐8) thin film is presented for carbon dioxide detection and sensing. The planar optical waveguides are made of polymethylmethacrylate and fabricated by hot embossing, which makes it flexible and cost‐efficient. Thin ZIF‐8...

The advancement of micro- and nanostructuring techniques in optics is driven by the demand for continuous miniaturization and the high geometrical accuracy of photonic devices and integrated systems. Here, UV-LED projection photolithography is demonstrated as a simple and low-cost approach for rapid generation of two-dimensional optical micro- and...

Small-scale optical components with micron or submicron features have grown in popularity in recent years. High-quality, high-efficient, and cost-effective processing approaches for polymer optics mass production are an urgent need. In this study, ultrasonic vibration will be introduced in embossing. The major advantage is that the required energy...

Self-written waveguides are an established solution to connect different optical elements with each other. They minimize coupling losses and enable a rigid connection. Furthermore, their characteristics enable a usage as thermal sensing element simultaniously.

In this paper, approaches for the realization of high-resolution periodic structures with gap sizes at sub-100 nm scale by two-photon polymerization (2PP) are presented. The impact of laser intensity on the feature sizes and surface quality is investigated. The influence of different photosensitive materials on the structure formation is compared....

3D metallic structures with symmetrically curved surfaces are proposed for surface plasmon polaritons (SPPs) deflection and concentration. Two-photon polymerization (2PP) and a sputtering process are applied for the preparation of the proposed structures. Leakage radiation microscopy (LRM) is used for the excitation and observation of SPPs. The cha...

Special integrated photonic surface structures composed of a dielectric semicircle ridge and a dielectric block placed on a metal substrate are proposed for the investigation of surface plasmon polariton (SPP) reflection and transmission effects. A fabrication method called microscope projection photolithography was employed for the preparation of...

In recent years, technological progress in nanotechnology has pushed struc-ture sizes to its limits. As an example, in the semiconductor industry, structures well below 100 nm are routinely produced. The characterization of such structures is a de-manding and very important task. Classical microscopy methods do not allow direct imaging in this regi...