Quantum Plasmon And Its Tomography In An Extraordinary Optical Transmission Process

Quantum entanglement is one of the most fantastic and unimaginable phenomenon in the quantum universe, with which, advanced technology like quantum communication and quantum computing can be realized. These science and technology have broken the limits of classics mechanism and gained a series of impressive achievements. Entanglement between the quadrature components of light fields, also known as continuous-variable entanglement, has become a hot field of research directions in quantum entanglement., whose characteristics are different from separate variables. An optical parametric amplifier based on the second-order nonlinear optical process can be an effective method to produce this continuous-variable entanglement light. This process with seed injected outputs two entanglement beams of EPR states.Plasmon has paid much attention by researchers in recent years, whose special characteristics make it a potential material in various kinds of field such as biology, energy, chemistry and information. When an incident beam traverses a metal film with periodic hole structure, a strong energy remains even if the size of the hole is far smaller than the wave length of incident light. This phenomenon called extraordinary optical transmission (EOT) provide a significant technical support for quantum system integration and quantum chip.With the help of our continuous-variable entanglement source, we fabricate a gold film with periodic hole structure to research the quantum characteristics of plasmon:1. Feedback-optimized extraordinary optical transmission of continuous-variable entangled states. The real transmissivity of our sample is 75%. We measure the entanglement level without and with the sample. The incident light has an original correlation variances of 2.7 dB amplitude sum and 2.1 dB phase difference. When the sample is inserted, remainder entanglement is 2.2 dB amplitude sum and 1.6 dB phase difference. This study confirms entanglement hold after a process called propagating surface plasmon polariton. Feedback technique is introduced to promote the measurement.2. Quantum process tomography (QPT) of EOT. The system for QPT is set up to measure and analyze EOT. We use maximum likelihood estimation to construct process matrix, which includes both amplitude distribution and phase change. The result of QPT suggests that EOT of plasmon can be equivalent to a neutral attenuator with the same transmissivity.