Who: Ivan Pshenichnyuk, Skolkovo Institute of Science and Technology, Russia
Place: Online seminar, Donostia International Physics Center
Date: Friday, 29 January 2021, 12:00
Achievements of modern electronics and photonics are remarkable, but the subsequent technological development requires the better integration of both. More intense usage of photons in logical and computational operations along with short distance communication can potentially improve the electronics significantly. To achieve that, a common integrated platform should be created where both electrons and photons can be efficiently manipulated. The integration of electronics and photonics at the level of microscopic chips is related to numerous challenges (like the size mismatch between components and weak light-matter interaction) and requires new approaches. One perspective approach is to manage electron-photon interaction at the fundamental level via the formation of hybrid light-matter quasiparticles. Two famous examples are exciton-polaritons and plasmon-polaritons. Many exotic hybrid states were demonstrated, including room temperature polariton condensates and plasmonic skyrmion lattices. Practical usefulness of both hybrids is also demonstrated. Multiple plasmonic improvements of photonic integrated devices make them smaller and faster.
Electro-optical modulators are going to play a key role in future integrated optoelectronics, comparable with a role of transistors in classical electronics. We propose a model of a compact modulator based on edge plasmons. To improve the modulation efficiency an integrated nanoscale waveguide mode is converted into a couple of subwavelength plasmons. The subsequent manipulation of charge distribution is used to influence the hybrid and perform the modulation. The usage of edge plasmons allows to overcome polarization restrictions typical for ordinary surface plasmons and make the device more flexible. To fight plasmonic losses a mixed circuit building style is used, when the light is converted to plasmons to perform the light-matter interaction operation (like modulation) and then it is converted back to the lossless waveguide mode. At the same time, a concept of fully semiconductor based plasmonic platform for integrated opto-electronic circuits is currently under development in our lab. The absence of metals potentially allows to decrease plasmonic losses significantly. However, the quality of surface plasmons in semiconductors is usually poor. We propose a mechanism where plasmons can be excited in very thin accumulation layers at the semiconductor/insulator boundary. Such layers support coupled pairs of surface plasmons that 'amplify' each other thus improving the quality factor of a pair. High tunability of accumulation layers allow to manipulate such modes with THz frequency. The proposed mechanism can be used to create a low loss tunable plasmonic waveguides and serves as a basis for the new circuit building strategy.
Host: Pedro B. Coto