Research
1. Quantum photonic integrated circuits
Quantum optical chips based on
conventional waveguides generally have large size and fail to
manipulate the polarization of photons, which is one of the most
important degree of freedom when processing information with photons.
We propose a series of fundamental integrated quantum components,
including polarization beam splitter, polarizer, movable plasmonic
waveguide, and so on. Besides, phase shifter and polarization
rotator/converter are also proposed with conventional dielectric
waveguide. Recently, on-chip coherent conversion of photonic
quantum entanglement between different degrees of freedom has been realized. (Opt. Lett. 36,
3630 (2011); Appl. Phys. Lett. 100, 041104 (2012); IEEE
Photonics Technology Letters 24,
434-436 (2012); Appl. Phys. Lett. 101, 071114 (2012); Opt.
Express 21, 17097-17107
(2013), Nat. Commun. 7 11985(2016).)
2. Quantum plasmonics
Silver nanowires as plasmonic components have been investigated
extensively in both theoretical and experimental studies. They are
quite useful in many applications, such as enhanced light-emitting,
photonic device fabrication, sensors, lasers, and nonlinear optics. We report
the coupling of photons from an optical fiber taper to surface plasmon
modes of silver nanowires. The coupling efficiency can be modulated by
adjusting the cross angle and the polarization of the input light.. We
realized the transmission of quantum polarization entanglement through this nanoscale
hybrid waveguide. The silver nanowire can
also work as nanoantenna, and the
polarization of its radiation can be tuned through the incident
polarization. We also observe the quantum
interference of single surface plasmons with integrated plasmonic
waveguide, and the visibility of interference fringes can reach 90%. (Appl. Phys. Lett. 95, 221109 (2009); Physica E 42, 1751–1754 (2010); Appl.
Phys. Lett. 99, 061103
(2011); J. Phys. Chem. C 116,
23779-23784 (2012); Laser & Photonics Rev. 7, 901-919 (2013); Phys. Rev. Appl. 2 014004 (2014), Nano lett. 15, 2380(2015))
3. Photonic OAM in plasmonic structures
We present experimental evidence that
high-dimensional orbital angular momentum entanglement of a pair of
photons can survive after photon-plasmon-photon conversion. The
information of spatial modes can be coherently transmitted by surface
plasmon polaritons. The experiment primarily studies the high
dimensional entangled systems based on subwavelength plasmonic
structures. Besides, such plasmonic structures can be used for
information encoding and detection. (Opt. Lett. 31, 2792 (2006); Europhys. Lett. 76, 753 (2006); Appl. Phys. Lett. 95, 111111 (2009); Opt. Express 20, 24151 (2012); Sci. Rep. 3, 2402 (2013).)
