Upcoming Talks

2022-10-12 11:00:00

Bo-Han Wu The University of Arizona

Continuous-variable photonic quantum information processing

Photonic quantum information processing is a type of information processing based on the principles of quantum optics. Continuous-variable (CV) quantum information of photons underpins a variety of quantum sensing and communication applications. Various of these quantum applications involve the generation and distribution of the two-mode squeezed vacuum (TMSV) state photons. My research topics cover these important subjects and can be divided into three parts. First, I theoretically proposed an integrated photonic platform for the generation of TMSV photons and experimentally fabricated the structure on the chip to successfully carry out these TMSV photons on the chip. This part is compatible with complementary-metal-oxide-semiconductor (CMOS) technology and paves the road of mass production of quantum integrated photonic platforms. Second, I theoretically proposed a CV quantum repeater architecture with the assistance of quantum error correction (QEC) and optical Gottesman-Kitaev-Perskill (GKP) state to realize long-haul entanglement establishment with high fidelity. To prove its usefulness, I applied these protocols on two representative use cases for quantum communication and sensing. Once optical GKP states with sufficient squeezing become available, the proposed QR architecture will enable CV quantum states to be faithfully transmitted over unprecedented distances, thereby making a large stride forward in the development of quantum technology. Finally, I theoretically proposed a quantum-radar scheme by transmitting the pulse-compression microwave field for investigating the direction of a distant object with higher sensitivity than the classical counterpart. This work generalizes the previous results in quantum radar ranging in [Phys. Rev. Lett. 128, 010501 (2022)] towards a general quantum radar detection system capable of detecting various properties of targets.

Speaker's Bio

Bo-Han Wu is currently a Physics PhD candidate at the University of Arizona in the US and received his MS degree in National Tsing Hua University and BS degree in National Chiao Tung University in Taiwan. He has a broad interest in quantum information science that covers both theory and experiment. During his PhD experiment study, he designed, fabricated and tested the photonic chip to generate the on-chip continuous-variable (CV) entangled photon; In his PhD theory study, he proposed a protocol of CV quantum repeater to distribute long-distance entanglement and a quantum radar scheme to interrogate the direction of an distant unknown object with experimentally feasible parameters. During his MS study, he was experienced in theoretical modeling of electromagnetically induced transparency (EIT) based quantum memory in cold atomic system.

2022-10-26 11:00:00

Cheng-Wei Qiu National University of Singapore

van der Waals interfacial nano-optics and low-dimensional metasurfaces

Metasurfaces and low-dimensional materials have been developing as two important candidates in the interfacial engineering, providing a plethora of new possibilities in novel optoelectronic functions and applications. The synergies between those two domains hold great promises in manipulating light-matter interaction. In this talk, I will start from reviewing and reporting some of the most recent developments in plasmonic and dielectric metasurfaces, and then focus on how monolayer TMDC and layered 2D materials could be hybridized with classic metasurfaces to modulate and structure novel light behavior, such as zero-dark-current and bipolar semimetal photodetector, monolayer meta-lens of atomic thickness, hybrid designs with enhanced SHG, PL, and tunable structural colors, by the coordinated hybridization between those two parties. Finally, we will elaborate our new breakthrough on van der Waals polaritonic metasurfaces, as a new roadmap toward ultra-low loss, long-range propagation, topological interfaces, and tailorable on-chip integrated functional devices.

Speaker's Bio

Prof. Cheng-Wei Qiu was appointed Dean’s Chair Professor twice (2017-2020 & 2020-2023) in Faculty of Engineering, NUS. He was Fellow of The Electromagnetics Academy, US. He is well known for his research in structured light and interfaces. He has published over 400 peer-reviewed journal papers. He was the recipient of the SUMMA Graduate Fellowship in Advanced Electromagnetics in 2005, IEEE AP-S Graduate Research Award in 2006, URSI Young Scientist Award in 2008, NUS Young Investigator Award in 2011, MIT TR35@Singapore Award in 2012, Young Scientist Award by Singapore National Academy of Science in 2013, Faculty Young Research Award in NUS 2013, SPIE Rising Researcher Award 2018, Young Engineering Research Award 2018, and Engineering Researcher Award 2021 in NUS, and World Scientific Medal 2021 by Institute of Physics, Singapore. He was Highly Cited Researchers in 2019, 2020, 2021, 2022 by Web of Science. He has been serving in Associate Editor for various journals such as JOSA B, PhotoniX, Photonics Research, and Editor-in-Chief for eLight. He also serves in Editorial Advisory Board for Laser and Photonics Review, Advanced Optical Materials, and ACS Photonics.

2022-11-02 11:00:00

Nicolas Joly Friedrich-Alexander University and Max-Planck Institute for the Science of Light

Fibre-based non-classical sources

Photonic crystal fibres (PCF) consist of a microstructured cladding of periodically arranged air-channels surrounding the core region. They are an ideal platform for all sort of nonlinear optics experiments ought to the possibility to adjust nonlinearity and dispersion. These parameters are easily adjustable at the fabrication stage. Alternatively, pressurizing the fibre is a good way to modify online the dispersion landscape so as to ensure the phase-matching conditions required for a particular effect. We will present in this talk several experiments using pressure-assisted nonlinear optics for the generation of quantum optics sources. First, we will show broadly tunable photon-pair generation in a suspended core fibre that we filled with argon gas [Phys. Rev. Res., 2, 012079 (2020)]. When the hollow-core fibre is filled with noble gas i.e., monatomic, the fluid serves as the gain medium. Not only we can then adjust the dispersion landscape of the fibre but we can even prevent the Raman scattering originating from random molecular vibrations, that yields unwanted noise and degrades the quality of the fibre-based sources. Such a versatile system is becoming a promising platform in quantum optics as it allows the generation of frequency tunable pairs of photons through four-wave mixing or modulational instability [PRA 95, 053814 (2017)]. We will show in this presentation the creation of correlated photon pairs with frequency separation up to over an octave [Opt. Lett. 46, 4033 (2021)]. By contrast, we will see that if a coherent pattern of molecular vibrations is first prepared, stimulated Raman scattering can be utilized within its lifetime for thresholdless conversion of single photons, provided certain phase-matching conditions are fulfilled. We recently demonstrated frequency up-conversion of single photon by 125 THz, while preserving the correlation of the original entangled pair [Science, 376, 621 (2022)]. Finally, we will discuss the latest advances on the generation of triplet states, which can be regarded as the reverse process of the generation of third harmonic.

Speaker's Bio

Nicolas Joly is an associate professor at the University of Nüremberg-Erlangen, where he works on photonic crystal fibers. He is also the head of the "microstructured optical fibres" research group at the Max-Planck Institute for the Science of light in Erlangen. His domain of research includes nonlinear optics as well as quantum-optics in PCF. In particular he is very interested in the nonlinear generation of new frequencies like supercontinuum generation or the generation of non-classical states of light using PCF.
The Optics and Quantum Electronics Seminar Series is supported by the Research Laboratory of Electronics (RLE) and the Department of Electrical Engineering and Computer Science (EECS).

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