Dr. Mohsen Rahmani is an ARC Discovery Early Career Research Fellow (level C) at the Australian National University (ANU). He graduated with a MSc from Kiev Polytechnic Institute (National Technical University of Ukraine) and PhD from National University of Singapore followed by two years at Imperial College London as a research associate. In 2015, Dr. Rahmani joined The Australian National University to pursue his research activities in Nonlinear Physics Centre at Research School of Physics and Engineering. His research interests cover various couplings and light-matter interactions, as well as filed Imaging and phase control at ultra-subdiffraction scales. Dr. Rahmani has authored/co-authored more than 40 Journal papers, and his H-index is 22. His research results have received highlights in Sydney Herald Morning, The Australian, New Scientist, Science Daily, etc., together with a number of interviews with various ABC channels, SBS, etc.
My research is concentrated on developing the new class of nanoscale surfaces (metasurfaces) that offer new capabilities to today’s miniaturised consumer devices. My metasurfaces have a wide range of applications including, but not limited to:
Night vision: Our ultra-thin metasurface film made of AlGaAs crystals was employed to convert light frequencies directly from infrared to visible. The use of such optical process for frequency conversion eliminates the need for a transition from the optical to the electronic domain and allows for ultimate miniaturisation of the night vision devices. This is a key innovation, patented by the ANU, which was considered impossible just a few years ago (see Video here).
Smart optics: All high-tech devices still use actual optical components (e.g. lens or mirrors) to shape the wavefront via propagation through media of given refractive indices to control the optical path. In 2017, we realised realise a smart metasurface, consisting of designed and fabricated dielectric nanoparticles on a single layer. This metasurface not only can reproduce the function of bulky optics but also can control the light propagation direction on demand. For example, when heated or cooled, the optical properties of the metasurface change meaning they can be reliably, and reversibly, manipulated to allow light to pass or reflect it (see Video here).
Ultra-sensitive detectors: We have developed a novel sensor, comprising of tailored fractals of dielectric TiO2 nanoparticles on a resonant metallic metasurface. Such a hybrid metasurface allows for enhancing the interaction of the optical near-field with a gaseous environment and also significantly increases the active area for gas condensation. We demonstrated how an optimal metasurface is able to detect refractive index changes lower than 8x10-6 in a gas mixture, a new world record, achieving selective detection of gas molecules with outstanding sensitivity of 137345 nm/RIU. This unique sensor can be applied for contactless non-invasive medical sensing, through detection of ultra-low concentrations of biomarkers expelled by the body through the breath (see Video here).