• Tunable plasmonic devices by integrating graphene with ferroelectric nanocavity

    分类: 光学 >> 量子光学 提交时间: 2023-02-19

    摘要: Graphene plasmons are able to become the fundermental of novel conceptual photonic devices, resulting from their unique characteristics containing excitation at room temperature and tunable spectral selectivity in different frequencies. The pursuit of efficiently exciting and manipulating graphene plasmons is necessary and significant for high-performance devices. Here, we investigate graphene plasmon wave propagating in ferroelectric nanocavity array. We experimentally show that the the periodic ferroelectric polarizations could be used for doping graphene into desired spatial carrier density patterns. Based on a theoretical model that considers periodic ununiform conductivity across graphene sheet, the simulation results show surface plasmon polaritons (SPP) in graphene can be excited by an incident light in a similar way to the excitation of photonic crystal resonant modes. The graphene SPP resonance can be tuned from ~720 to ~1 000 cm-1 by rescaling the ferroelectric nanocavity array, and from ~540 to ~780 cm-1 by dynamically changing the applied gate voltage. Our strategy of graphene carrier engineering to excite SPP offers a promissing way for large-scale, non-destructive fabrication of novel graphene photonic devices.

  • A power-free graphene mid-infrared photodetector array

    分类: 光学 >> 量子光学 提交时间: 2023-02-19

    摘要: Graphene plasmons can resonantly enhance the incident light absorption and offer a potential for tunable spectral selectivity for mid-infrared (MIR) detection. High-performance tunable graphene plasmonic devices are, however, typically based on electrode-patterned graphene, which requires high power input and are technologically challenging in compact assembly. Here we demonstrate a tunable MIR photodetector array operating at zero input bias voltage. Our devices consist of integrating monolayer graphene with periodically "type-printed" ferroelectric superdomain. The spatial graphene carrier density patterns can be readily modulated by artificially defined ferroelectric superdomain with periodic nanoscale-wide stripe domains, achieving nonuniform pattering of conductivity and subsequently enabling graphene plasmons excitation and confinement for a selective transmission resonance in MIR regime. A high photoresponsivity of ~30 mA W-1 at room temperature is achieved in our device. We also observe that our device array features a tunable detection performance with spectral selectivity from 7.2 to 8.5 {\mu}m by directly reconfiguring the periodicity of ferroelectric superdomain. Our strategy could lead to the development of smart fabrication of on-chip MIR photodetector array for application of tunable spectral systems with low-energy consumption.