Jun-Yong Yan ’s paper “Coherent control of a high-orbital hole in a semiconductor quantum dot” was published in the journal Nature Nanotechnology. (Nat. Nanotechnol. 18(10), 1139–1146 (2023)) Coherently driven semiconductor quantum dots are one of the most promising platforms for non-classical light sources and quantum logic gates which form the foundation of photonic quantum technologies. However, to date, coherent manipulation of single charge carriers in quantum dots is limited mainly to their lowest orbital states. Ultrafast coherent control of high-orbital states is obstructed by the demand for tunable terahertz pulses. To break this constraint, we demonstrate an all-optical method to control high-orbital states of a hole via stimulated Auger process. The coherent nature of the Auger process is proved by Rabi oscillation and Ramsey interference. Harnessing this coherence further enables the investigation of single-hole relaxation mechanism. A hole relaxation time of 161 ps is observed and attributed to the phonon bottleneck effect. Our work opens new possibilities for understanding the fundamental properties of high-orbital states in quantum emitters and developing new types of orbital-based quantum photonic devices.

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Xiaoyi Wang’s paper “Stepwise irradiative engineering based on Einstein quantum theory for promoting PVA/TiO2 photocatalytic activity at minimized irradiance consumption” was published in Applied Surface Science. Hampered by insufficient in band quantum yield, the polymer/semiconductor hybrid photocatalyst is considered to be far from industrial applications. In recent progress, material modification and new material development are the major concepts for improving in-band quantum yield. However, Promoting photocatalytic performance by modulating external irradiation field has been ignored so far in both photocatalytic theory and applications. Here, based on the Einstein quantum theory, we have successfully developed a stepwise irradiative technique, where the photocatalytic performance of PVA/TiO2 hybrid system can be improved by 15% with nearly halved irradiance consumption (55%). It is believed that these findings might push photocatalytic efficiency into higher steps with the assistance of a deep understanding of irradiative theory and engineering, which expect to be useful for future industrial application. The work has been published in a reputed Journal: Applied surface science, Dr Xiaoyi Wang and Mr Wenyu Hu has conducted the work under the supervision of Prof Chaoyuan Jin.  https://doi.org/10.1016/j.apsusc.2022.154145

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On June 16, Professor Jin Chaoyuan of the Ultrafast Photonics Laboratory carried out the demonstration meeting of the key special project of the national key research and development plan “information photonic technology”, and more than 50 teachers, students and experts of the School of Information and Telecommunications listened to the demonstration meeting through the combination of online and offline.

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In this paper, we conduct a comprehensive review of the field of optical neural networks, summarize and analyze the research results in this field, and propose some possible future research directions. Also, we select Semiconductor Optical Amplifier (SOA) to carry out the simulation experiment of a neural network, apply the SOA model in the handwritten digital recognition experiment, and the accuracy of recognization achieve 92%, proposing the possibility of photoelectric fusion.

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Lingfang Wang’s paper “Mode selection in InGaAs/InGaAsP quantum well photonic crystal lasers based on coupled double-heterostructure cavities” was published in Optics Express ( Vol. 30, Issue 7, pp. 10229-10238 (2022) ). Photonic crystal lasers with a high-Q factor and small mode volume are ideal light sources for on-chip nano-photonic integration. Due to the submicron size of their active region, it is usually difficult to achieve high output power and single-mode lasing at the same time. In this work, we demonstrate well-selected single-mode lasing in a line-defect photonic crystal cavity by coupling it to the high-Q modes of a short double-heterostructure photonic crystal cavity. One of the FP-like modes of the line-defect cavity can be selected to lase by thermo-optically tuning the high-Q mode of the short cavity into resonance. Six FP-like modes are successively tuned into lasing with side mode suppression ratios all exceeding 15 dB. Furthermore, we show a continuous wavelength tunability of about 10 nm from all the selected modes. Link: https://opg.optica.org/oe/fulltext.cfm?uri=oe-30-7-10229&id=470324

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In 2022,Huiwen Deng published a research paper titled “The role of different types of dopants in 1.3 μm InAs/GaAs quantum-dot lasers” in Journal of Physical D. This paper presents a study on the effect of the direct Si doping technique on high-density InAs/GaAs QDs grown on native substrates. Considering the proper doping methods, high-performance InAs/GaAs QD lasers with unintentional doped, p-type modulation-doped and n-type doped active regions have been demonstrated, revealing the impacts of dopants. The applied Si dopants can reduce the threshold current density of lasers, narrow the near field lasing spot while accelerating the lasing mode switch with a short cavity at a high operating temperature. In contrast, the Be dopants can promote high-temperature performance at the expense of increasing the threshold current density. 文章链接：https://iopscience.iop.org/article/10.1088/1361-6463/ac55c4/meta

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In February 2022, Junyong Yan published a research paper titled “Double-Pulse Generation of Indistinguishable Single Photons with Optically Controlled Polarization” in Nano Letters. Single-photon sources (SPSs) play a key role in linear optical quantum computing and solid-state quantum networks. So far semiconductor self-assembled quantum dots, as “artificial atoms” with high stability and easy integration into high-quality factor microcavites, have been demonstrated to be used to produce high-purity indistinguishable single photons under pulsed resonance excitation. However, traditional pulsed resonance fluorescence techniques usually require polarization filtering in order to extract single-photon signals from excitation pulses, but due to the lack of active control technology for generating single-photon polarization states, this filtering technique will lead to at least 50% loss of brightness of SPS devices, which directly reduces the scalability of SPSs. In this work, we demonstrates a double-pulse excitation(DPE) scheme that is easy to filter out excitation laser and can generate single-photon sequences with optically controlled polarization. We demonstrated that the DPE scheme not only does not sacrifice the single-photon purity and indistinguishability of single photons, but also can exceed the 50% limitation of device brightness. This scheme is realized by exciting the quantum dot to the biexciton state and subsequently driving……

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