Quantum Optoelectronics

Abstract:

Thyroid cancer remains prevalent worldwide, with its incidence steadily increasing in recent decades. Although ultrasonography is currently the primary screening method in clinical practice, its relatively low specificity has contributed to increased overdiagnosis. Furthermore, conventional ultrasonography is associated with challenges such as high inter- and intra-observer variability and limited functional imaging capabilities, which together reduce its diagnostic accuracy. To address these limitations, researchers have explored complementary image-based techniques to assess the vascularity surrounding cancerous nodules. This comprehensive review provides an overview of recent clinical trials investigating advanced ultrasound (US)-based imaging techniques for diagnosing thyroid cancer in humans. Specifically, we explore the use of photoacoustic imaging and ultrafast US Doppler techniques, highlighting their potential to enhance triaging accuracy by enabling the analysis of both structural and functional characteristics of thyroid nodules in vivo. Integrating these innovative approaches into existing ultrasonography protocols could significantly enhance the precision of thyroid cancer diagnosis.

Abstract:

Green ammonia evolution by photocatalytic means has gained significant attention over recent decades, however, the energy conversion efficiency remains unsatisfactory, and deep mechanistic insights are absent. Here in this work, this challenge is addressed by developing a photothermal system that synthesizes ammonia from nitrogen and natural seawater under simulated solar irradiation, employing ruthenium‐doped barium tantalum oxynitride semiconductors. This method significantly enhances solar‐to‐ammonia conversion efficiency, providing a viable alternative to the energy‐intensive Haber–Bosch process. Optimized at 240 °C, the system achieves an ammonia evolution rate of 5869 µmol g−1 h−1 in natural seawater. Moreover, detailed characterizations have shown that the use of seawater not only leverages an abundant natural resource but also improves the reaction kinetics and overall system stability. The catalysts maintain their activity and structural integrity over multiple cycles, demonstrating both the feasibility and the durability of this innovative system. Achieving a solar‐to‐ammonia efficiency of 13% and an overall energy conversion efficiency of 6.3%, this breakthrough highlights the potential to decentralize ammonia production, enhancing accessibility and sustainability. This approach combines the benefits of thermal and photocatalytic processes, marking a significant advancement in ammonia synthesis technology.

Abstract:

We have estimated the intrinsic complex refractive index spectrum of a CsPbBr3 nanocrystal. With various dilute solutions of CsPbBr3 nanocrystals dissolved in toluene, effective refractive indices were measured at two different wavelengths using Michelson interferometry. Given the effective absorption spectrum of the solution, a full spectrum of the effective refractive index was also obtained through the Kramers–Krönig relations. Based on the Maxwell–Garnett model in the effective medium approximation, the real and imaginary spectrum of the complex refractive index was estimated for the CsPbBr3 nanocrystal, and the dominant inaccuracy was attributed to the size inhomogeneity.

Abstract:

Data for paper on plasmonic enhanced emission from perovskite nanowires

Abstract:

The optical Aharonov-Bohm effect in a quantum ring was investigated in terms of magnetic field dependence of excitons and biexcitons. The fine exciton states of quantized orbital angular momentum in a quantum ring were considered theoretically, and the presence of quantum beats was predicted as evidence of the quantum coherence of the fine exciton states. In the case of GaAs/GaAlAs quantum rings grown by the droplet epitaxy, we found various disorder effects are associated such as structure anisotropy, localization, and internal electric field, resulting in a modulation of the oscillation periods. Additionally, we found that a strongly correlated exciton pair can be formed in a single quantum ring similar to the Wigner molecule. In this case, the biexciton emission energy changes abruptly at transition magnetic fields with a fractional oscillation period compared to that of the exciton, the so-called fractional optical Aharonov-Bohm oscillations.