United States

Controlling light-matter interaction with molecular vibrations in mid-infrared resonators offers exciting new research opportunities in chemistry and physics [1]. Laboratory implementations use standard materials, operate at room temperature, and use traditional fabrication and detection techniques, yet they have deeply challenged our fundamental understanding on the connections between cavity quantum electrodynamics and chemistry. We have developed rigorous microscopic quantum theory to describe the optical and chemical properties of realistic molecular vibrations in infrared cavity resonators with non-perturbative light-matter interaction [2,3]. We can successfully describe the linear and nonlinear spectra of vibrational polaritons [4]—hybrid vibration-cavity eigenstates– and realistically study the dissociation dynamics of cavity-coupled molecular bonds under non-adiabatic conditions [5]. The role of symmetry of the ground state electronic density with respect to nuclear displacements in the dynamics of vibrational polaritons is discussed, and future applications of these systems for the generation of THz quantum light are suggested.

AIPP Photonics in Chemical Physics

Strong light-matter coupling with molecular vibrations in infrared resonators

cavity chemistry

vibrational polaritons

cavity quantum electrodynamics

molecular nanophotonics

coherent control

**BQIT is a three day annual workshop** aimed at enabling leading UK and international academics and industrial partners to come together; to explore and discuss future ambitions and challenges in the field of **Quantum Information Technologies.** Since our conception in 2014 we have had 230 speakers and panellists who have presented their work and opinions on a range of topics, from quantum theory to innovation in industry.


### Welcome Message
The BQIT:21 team welcomes you to the eighth Bristol Quantum Information Technologies workshop! 

Last year was the first time in our workshop's history that we had gone fully virtual. The global circumstances that continue to impact us all professionally and personally have forced BQIT once again to be delivered as an all-virtual workshop for 2021. The access this creates to colleagues across the world who would otherwise be unable to join us, as well as being able to make the workshop free for all attendees due to the lower costs involved in delivering an online workshop, are just a couple of the extraordinary benefits of meeting online. This also means that we can welcome three times as many attendees to BQIT than previous years.   

We take this opportunity to thank each of our speakers and poster presenters for contributing their technical content, this year's sponsors, whose support this year enabled BQIT:21 to be free to all attendees, and to all of our attendees for joining us online this year. We recognise the extra energy required to stay connected and motivated during these difficult times, and are hugely encouraged to see so many of you willing to continue to connect with us on an online platform. 

It is our hope that you have a productive and enjoyable time while you engage and interact with BQIT:21, and to everyone that has helped take BQIT:21 online, thank you! 

**The BQIT board and organisation team **


![](https://assets.underline.io/uploads/markdown_image/1/image/a12e0c1ad3410144cb48557690e4ecaf.png)
### This year's workshop agenda is available here: [Virtual BQIT:21](https://drive.google.com/file/d/1QwsSM0ztnxC_lgUKf3TbO3GvnI44AQkY/view?usp=sharing)
For further information, please contact us at: **bqit-admin@bristol.ac.uk**

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Bristol Quantum Information Technologies Workshop

poster

The field of photonics, broadly defined, ranges from basic physical work on lasers and ultrashort laser pulses to applications in healthcare, communications, and materials. With its increasingly diverse disciplines and subdisciplines, photonics has become a key component in modern society. The scientific program consists of cross-disciplinary researchers, including chemists, physicists, and engineers, in both theory and experimentation. These researchers will discuss this rapidly expanding field and cover topics that address the latest advances in photonics related research and debate the current needs and priorities, as well as the emerging areas.

To access the AIPP Photonics in Chemical Physics conference, [please remember to register.  ](https://services.aip.org/AIPPHorizons/?confID=3351210)

The field of photonics, broadly defined, ranges from basic physical work on lasers and ultrashort laser pulses to applications in healthcare, communications, and materials. With its increasingly diverse disciplines and subdisciplines, photonics has become a key component in modern society. 

NMR provides a non-destructive spectroscopic technique for determining the chemical structure of molecules, but its sensitivity is absolutely low because the nuclear spin polarization is low. One method to improve the sensitivity of NMR is Dynamic Nuclear Polarization (DNP). In DNP, the polarization is transferred to nuclear spins from electron spins with a high polarization ratio only at cryogenic temperatures. In contrast, DNP using photo-excited triplet electron spins (triplet-DNP), can achieve high sensitivity of NMR under higher temperature conditions. However, triplet-DNP of biomolecules has not been achieved because conventional acene-based polarizing agents aggregate in hydrophilic biomolecular crystals. Here we report triplet-DNP of erythritol-d4, a hydrophilic molecular crystal using a hydrophilic porphyrin derivative (TCPPNa) as a novel polarizing agent. Interestingly, TCPPNa maintains its triplet electron spin polarization even when it is aggregated in erythritol-d4 crystals. We achieved about 120 times enhancement of the 1H NMR signal intensity of erythritol-d4 by using slightly aggregated TCPPNa.

Triplet Dynamic Nuclear Polarization of Biomolecules Using Porphyrin Aggregates

Trivalent europium ions (Eu(III)) exhibit high color purity, but their absorption coefficients are very small. Eu(III) complexes that utilize energy transfer from antenna ligands to a metal center have been developed to produce efficient luminescent materials. Nevertheless, their energy transfer mechanisms, which depend on the kinds of ligands and their configurations, are still elusive due to weak and complicated interactions between organic ligands and lanthanide ions. To elucidate the energy transfer mechanisms, we measured the temporal changes of emission and absorption spectra using time-resolved photoluminescence (TR-PL) and transient absorption (TA), respectively. We compared the intramolecular energy transfer of the mononuclear complex and the dinuclear complex. Although they have identical antenna chromophores, the dynamics of the two complexes are different. The lifetime of the ligand S1 state in the dinuclear complex is faster than in the mononuclear complex. By comparing molecular geometries between the complexes, we concluded that this difference originated from the difference in the relative configuration of the two triphenylenes. Our discovery helps to establish the design strategy of highly efficient luminescent lanthanide complexes in photofunctional materials.

Energy transfer dynamics in luminescent Eu(III) complexes with phosphine oxide ligands


In this study, optical deep-level transient spectroscopy (O-DLTS) has been employed to investigate trap properties in the p-GaN/AlGaN heterostructure, the key part of such a normally-off enhancement-mode III-N transistors. Three electron traps labeled as E1, E2, and E3 were extracted by O-DLTS. The temperature-enhanced emission process of E3 has been studied by isothermal mode O-DLTS.



Study of Traps in p-GaN Gate HEMT by Optical DLTS

The new trends in biosensing field involves fast and real-time identification of biomarkers for rapid diagnosis with less-invasive methods by means of low-cost miniaturized and portable point of care devices. The ability of plasmonic systems to confine the light at nanometer dimension and manipulate the light with size, shape and material features, makes these systems promising candidates for biomedical devices. In this work we demonstrate the sensing capability of compact arrays of 3D metal dielectric core-shell chiral nano helices-based metamaterial enabled by the engineering of many technological elements. On one hand, the intrinsic chiral geometry of these structures, realized by Focused Ion Beam Induced Deposition technology, makes the system unaffected by background interferences, allowing to work even in optically dense environments like body fluids. Moreover, the metal-dielectric architecture realized through a conformal coating of a functional polymeric layer, enhance the chiroptical plasmonic properties of the chiral metamaterial in the far and near- field, and offers a large surface to suitable for molecular immobilization, together with the extrusion along the third dimension. We recorded refractive index sensitivity of about 800nm/RIU and FOM= 1276 RIU-1 for different concentration of glycerol-water solution. We also demonstrated the detection abilities to surface-specific binding event with the Tar-Dna binding protein, TDP-43, currently under study as biomarker for early-stage detection of neurodegenerative diseases. We successfully tested the sensor at different molar concentrations ranging from 1pM down to 10 fM, and in different environment, like human serum. We believe that our finding provides new perspectives for novel diagnostic tools.

3D Helix-based Metamaterial Arrays for Femtomolar Biodetection

Stepwise two-photon absorption (2PA) processes are becoming an important technique because it can achieve high reductive photochemical reactions with visible and near infrared light and intensity-gated high spatiotemporal selectivity with much lower power thresholds than those of the simultaneous 2PA. However, excited states generated by stepwise 2PA (higher excited states and excited states of transient species) are so short-lived that the efficiency for the stepwise 2PA induced photochemical reactions is usually quite low, which limits the versatility for this technique. Here, we demonstrated that the electron of the higher excited state can be efficiently extracted in a nanohybrid of organic molecules and wide bandgap semiconductor nanocrystals (NCs).1 Using perylene bisimide (PBI)-coordinated CdS NCs as a model compound, we demonstrated that the electron of the higher excited state of PBI generated by stepwise 2PA can be extracted to the conduction band of CdS NCs with a quantum yield of ∼0.5–0.7. Moreover, the extracted electron survives at the conduction band of CdS NCs over nanoseconds, which is more than hundred times longer than the lifetime of the higher excited state of PBI. This method can be applied to other organic molecules and larger wide bandgap semiconductors, and therefore, will expand the versatility for the photochemical reactions utilizing the short-lived excited states.

Green and far-red-light induced electron injection from perylene bisimide to wide-bandgap semiconductor nanocrystals with stepwise two-photon absorption process

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Triplet Dynamic Nuclear Polarization of Biomolecules Using Porphyrin Aggregates

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