Executive Summary : | The research proposal is to design, model, fabricate and characterize terahertz (THz) metamaterials which can exhibit quantum mechanical Parity-time (PT) symmetry effect. Terahertz (THz) frequencies (0.1 - 10 THz) of electromagnetic (e.m.) spectrum have been widely explored in last two decades which provides potential applications based on waveguide and metamaterial structures. The radiation of 1 THz corresponds to wavelength of 300μm, which lies in quantum realm. The physical phenomena which involves the dimension of the order of micrometer, exhibit quantum mechanical properties. Therefore, it is quite interesting to discover quantum phenomena in terahertz regime of e.m. spectrum which leads to several applications in modern era. In this regard, one quantum mechanical phenomenon called parity-time (PT) symmetry, discovered by Bender et al. in 1998, was first introduced in photonics in 2010. There are distinguished applications of PT symmetric systems such as beam switching, coherent perfect absorber, planar focusing, transmission line networks etc. Further breaking of PT symmetry through exceptional point (EP) leads to applications like super-absorbing meta-surface, bio?sensing, actively controlled phase transition, etc. There are very limited number of articles have been published on PT symmetry effect and its breaking in terahertz regime as per recent international status. specifically in case of national status, no one has published work on it till date to the best of our knowledge. Therefore many scopes are there to explore PT symmetry effect based on THz radiations to investigate distinguished phenomena and applications of terahertz metamaterials viz. electromagnetically induced transparency, near field coupling, bio -sensing, perfect absorber, etc. In this aspect, we are proposing PT symmetric terahertz metasurface consisting of orthogonally placed meta-molecules which exhibit two different Eigen frequencies. In this proposal, we will design, fabricate and characterize metamaterials structure under the excitation of terahertz radiation in direct transmission approach. Due to the coupling between the nearby meta-atoms, the two eigen frequencies exhibit PT symmetry effect, which further leads to exceptional point followed by broken PT symmetry. As a result, we can achieve PT symmetry breaking in terahertz metamaterials, and investigate different applications as mentioned above. |