Enhanced Quantum Emission By Doubly-resonant Topological Tamm Cavities

Since the discovery of the quantum Hall effect,various topological states have been widely studied such as topological insulators and topological semimetals.In addition to condensed electron systems,they have been found in various other physical systems,including cold atomic lattices,photonic crystals,phonon crystals,coupled resonator arrays,superconfigurable materials,etc.The most important characteristics of the topology are the edge state protected by topology.Such topological edge state can form topological resonant cavities in optical systems,which are utilized to enhance light-matter interactions and change the emission properties of materials,realizing new types of topological lasers and quantum emission sources.Therefore,the use of topological microcavities to manipulate quantum emission has attracted considerable attention.But so far,most of these topological microcavities are single resonant cavities for either the pump laser wavelength or the emission wavelength of quantum emitters(QEs).Intriguingly,the higher emission efficiency of QEs can be achieved by placing them in the doubly-resonant cavity to simultaneously resonate for pump laser and emission wavelengths,which has been demonstrated in several works used micro-nano photonic structures,including doubly resonant nano-antennas and coupled optical resonant cavities.Although these structures can achieve resonance at two specific wavelengths,the pump laser and emission wavelengths cannot be tuned freely according to the needs of practical applications.Besides,since these doubly resonant micro-nano structures are not topologically protected,the emission of QEs are susceptible to various defects and the external environment.Therefore,the design of doubly resonant microcavities with topological property that can resonate at arbitrary pump laser and emission wavelengths has good practical applications.Unfortunately,to the best of my knowledge,very few works so far have reported on the doubly resonant topological microcavity with both tunable resonance of pump laser and emission wavelengths.The innovations of this paper are as follows: first proposing a method to enhance the emission of QEs using a special topological photonic system;i.e.,the asymmetric doubly-resonant topological Tamm microcavity.Such a structure has a remarkable feature with two freely tunable resonant modes to simultaneously achieve dual resonances at two arbitrary wavelengths according to the needs of practical application,and it is simple and easy-to-implement.In this work,our main research ideas are as follows:1.The doubly resonant topological Tamm structure,which can achieve resonance for arbitrary dual wavelengths,is constructed by transfer matrix.The effects of its mode characteristics and structural parameters on its optical properties are analyzed to pave the way for the next study of the quantum emission efficiency of embedded quantum emitters.2.Embedding the quantum emitters in the topological Tamm microcavity,which is in dual resonance with the pump laser wavelength and the emission wavelength of the quantum emitters.Based on the theoretical simulation results,the modulation of quantum emissions by coupling parameters and the structure parameters of doubly resonant structure are investigated,and the main physical mechanism is explained by the doubly-resonant cavity temporal coupled-mode theory.3.On this basis,the double enhancement of quantum emission by the doubly resonant structure is experimentally verified.In our experiments,we investigate the photoluminescence(PL)intensity and the emission decay rate of quantum emitters in three different cases.One case is that the pump laser wavelength locates at the resonant wavelength,whereas the emission wavelength of QEs is away from the resonant modes.Another case is the opposite condition that the emission wavelength of QEs is at the resonant mode,while the pump laser wavelength is not.In the last case,both the pump laser wavelength and emission wavelength of QEs are at the resonant modes of our structure.Finally,we elaborate and analyze the experimental results in detail,which demonstrates that the doubly resonant structure matching both the pump laser wavelength and emission wavelength of quantum emitters can achieve double enhancement of quantum emission.we believe that our work demonstrates a promising platform for realizing giant enhancements of light-matter interactions,which have potential applications in optical detection,filtering,topological radiation sources,topological lasers,and quantum information.