Topic：Slow light enabled nanophotonic devices on Photonic Crystal Platform
Speaker：Prof. R.K.Sinha (CSIR-CSIO印度中央仪器科学组织主任;SPIE Fellow)
Time：October 10th 9：00-10:00
Location：Room 440, Teaching Building 3
Abstract：Slow light refers to reduction of the group velocity of the light wave propagating in a medium. This leads to increased light matter interaction strength, which enables increased time delay for optical signals as a key functionality for processing, storing and buffering optical signals. Photonic Crystal line defect waveguide is one of the most suitable platforms to generate and control the slow light. The dispersion curve of guided modes is used to determine the group velocity of light wave propagating through them. The realization of slow light effect in Photonic Crystal line defect waveguide due to flattening of dispersion curve can be achieved by numerous ways such as by changing hole sizes and shapes, infiltrating with dielectric material and by adjusting the position of holes adjacent to the waveguides. In this talk, Photonic crystal line defect waveguides in (a) silicon on insulator (SOI) platform and (b) Slotted photonic crystal waveguide will be described and the method to obtain optimized structural parameters for the design of (i) optical buffer in terms of delay bandwidth product (ii) Time and wavelength division multiplexure (iii) Optical spectral switch and (iv) generation of optical soliton at incredibly low optical power will be cover.
Topic：Optical Fiber Nanoantenna Fabrication and Research Applications: Nano-Photonics to Optical Tweezers
Speaker：Dr. Samir K Mondal (CSIR-CSIO印度中央仪器科学组织研究员)
Abstract：Optical antenna is a key element manipulating light into ultrasmall, nanometer-scale volume. It is becoming indispensable in nano-photonics research though difficulties arise in making a simple and efficient optical antenna. A unique method is introduced for preparation of an efficient optical fiber nanoantenna using simple etching technique and guided by simple rules of physics. The antenna shows interesting properties both in near-field and far field optics, which make it very promising in the interdisciplinary field of nano-photonics research. As a proof of the concept, couple experiments such as nano-optical tweezers, TERS, trapping and tweezing, topological charge mapping etc. have been studied resulting in interesting outcomes. There are also indications how the salient features of the antenna as well as etching technique can further be used for other device fabrication and applications like negative axicon and optical imaging.