OXIDE-BASED NOVEL LIGHT EMITTER AND TUNABLE ABSORBER

Abstract

There is a growing need for electrically driven fast on-chip optical transducers. Recently, devices driven by Inelastic Tunneling of electrons (IET) has been increasingly investigated for this application. In this thesis, we have used Pulsed Laser Deposition (PLD) to make extremely stable, repeatable, and reproducible tunnel junctions using novel epitaxial oxides. Emission from these devices are broadband with cut-off decided by applied bias voltage (hωmax < eVb). In addition to this, we have developed a novel approach to create tiny light emitting hot spots 'pinholes' using focused-ion beam. Emission from these bright hot spots produce photons with energy exceeding the applied bias voltage. Moreover, we have also demonstrated a tunable metasurface using phase change material VO2. For ease of demonstration, we have shown the tunable array of antennas in the THz spectral range. Eventually, these antenna arrays would be integrated for spectrally tunable detection/emission of photons.