Non-reciprocal devices, such as circulators and isolators, are indispensable components in classical and quantum information processing in integrated photonic circuits. Aside from these applications, ...the non-reciprocal phase shift is of fundamental interest for exploring exotic topological photonics, such as the realization of chiral edge states and topological protection. However, incorporating low-optical-loss magnetic materials into a photonic chip is technically challenging. In this study we experimentally demonstrate non-magnetic non-reciprocity using optomechanical interactions in a whispering gallery microresonator, as proposed in a previous work. Optomechanically induced non-reciprocal transparency and amplification are observed and a non-reciprocal phase shift of up to 40 degree is also demonstrated. The underlying mechanism of optomechanically induced non-reciprocity has great potential for all-optical controllable isolators and circulators, as well as non-reciprocal phase shifters in integrated photonic chips.
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IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SBMB, UL, UM, UPUK
The realization of optical non-reciprocity is crucial for many applications, and also of fundamental importance for manipulating and protecting the photons with desired time-reversal symmetry. ...Recently, various new mechanisms of magnetic-free non-reciprocity have been proposed and implemented, avoiding the limitation of the strong magnetic field imposed by the Faraday effect. However, due to the difficulties in separating the signal photons from the drive laser and the noise photons induced by the drive laser, these devices exhibit limited isolation performances and their quantum noise properties are rarely studied. Here, we demonstrate an approach of magnetic-free non-reciprocity by optically-induced magnetization in an atom ensemble. Excellent isolation (highest isolation ratio is Formula: see text) is observed over a power dynamic range of 7 orders of magnitude, with the noiseless property verified by quantum statistics measurements. The approach is applicable to other atoms and atom-like emitters, paving the way for future studies of integrated photonic non-reciprocal devices.
Non-reciprocal devices, which allow non-reciprocal signal routing, serve as fundamental elements in photonic and microwave circuits and are crucial in both classical and quantum information ...processing. The radiation-pressure-induced coupling between light and mechanical motion in travelling-wave resonators has been exploited to break the Lorentz reciprocity, enabling non-reciprocal devices without magnetic materials. Here, we experimentally demonstrate a reconfigurable non-reciprocal device with alternative functions as either a circulator or a directional amplifier via optomechanically induced coherent photon-phonon conversion or gain. The demonstrated device exhibits considerable flexibility and offers exciting opportunities for combining reconfigurability, non-reciprocity and active properties in single photonic devices, which can also be generalized to microwave and acoustic circuits.
Light is usually confined in photonic structures with a band gap or relatively high refractive index for broad scientific and technical applications. Here, a light confinement mechanism is proposed ...based on the photonic bound state in the continuum (BIC). In a low‐refractive‐index waveguide on a high‐refractive‐index thin membrane, optical dissipation is forbidden because of the destructive interference of various leakage channels. The BIC‐based low‐mode‐area waveguide and high‐Q microresonator can be used to enhance light–matter interaction for laser, nonlinear optical and quantum optical applications. For example, a polymer structure on a diamond membrane shows excellent optical performance that can be achieved with large fabrication tolerance. It can induce strong coupling between photons and the nitrogen–vacancy center in diamond for scalable quantum information processors and networks.
A light confinement mechanism is proposed based on the photonic bound state in the continuum. In low‐refractive‐index photonic structures on a high‐refractive‐index membrane, optical dissipation to the continuum can be forbidden because of the destructive interference of various leakage channels, without the requirement of other high‐refractive‐index materials.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Mean‐field treatment (MFT) is frequently applied to approximately predict the dynamics of quantum optics systems. It simplifies the system Hamiltonian by neglecting the quantum statistics of certain ...modes that are driven strongly by lasers or couple weakly with other modes. However, the neglected quantum correlations between different modes result in unanticipated quantum effects and might lead to significantly distinct system dynamics. Here, a general and systematic theoretical framework based on perturbation theory in company with MFT is provided to capture these quantum effects. The form of nonlinear dissipation and parasitic Hamiltonian as well as their relationship to the nonlinear coupling rate are predicted. Furthermore, the indicator is also proposed as a measure of the accuracy of mean‐field treatment. As an example, this theory is applied to quantum frequency conversion, in which mean‐field treatment is commonly applied, to test its limitation under strong pump and large coupling strength. The analytical results show excellent agreement with the numerical simulations. This work clearly reveals the residual quantum effects neglected by MFT and provides a more precise theoretical framework for nonlinear optics and quantum optics.
A general and systematic theoretical framework to reveal the nonlinear dissipations and parasitic interactions neglected by mean‐field approximation in traditional studies of quantum optics systems is developed. The indicator is proposed as a measure of the accuracy of mean‐field treatment. The theory provides an efficient tool to predict the dynamics of nonlinear and quantum optics systems with high precision.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
It is well known that many operations in quantum information processing depend largely on a special kind of quantum correlation, that is, entanglement. However, there are also quantum tasks that ...display the quantum advantage without entanglement. Distinguishing classical and quantum correlations in quantum systems is therefore of both fundamental and practical importance. In consideration of the unavoidable interaction between correlated systems and the environment, understanding the dynamics of correlations would stimulate great interest. In this study, we investigate the dynamics of different kinds of bipartite correlations in an all-optical experimental setup. The sudden change in behaviour in the decay rates of correlations and their immunity against certain decoherences are shown. Moreover, quantum correlation is observed to be larger than classical correlation, which disproves the early conjecture that classical correlation is always greater than quantum correlation. Our observations may be important for quantum information processing.
We demonstrate the collapse and revival features of the entanglement dynamics of different polarization-entangled photon states in a non-Markovian environment. Using an all-optical experimental ...setup, we show that entanglement can be revived even after it suffers from sudden death. A maximally revived state is shown to violate a Bell's inequality with 4.1 standard deviations which verifies its quantum nature. The revival phenomenon observed in this experiment provides an intriguing perspective on entanglement dynamics.
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CMK, CTK, FMFMET, IJS, NUK, PNG, UM
Obg-like ATPase 1 (OLA1) is a highly conserved GTPase, which was over expressed in a variety of malignant tumors, but its role in colorectal cancer (CRC) was poorly studied.
Three public CRC gene ...databases were applied for OLA1 mRNA expression detection. The clinical data of 111 CRC patients were retrospectively collected from the Second Affiliated Hospital of Zhejiang University (SAHZU) for OLA1 protein expression and Kaplan-Meier Survival analysis. OLA1 stably knocked out CRC cell lines were conducted by CRISPR-Cas9 for experiments in vitro and in vivo.
OLA1 was highly expressed in 84% CRC compared to matched surrounding tissues. Patients with OLA1 high expression had a significantly lower 5-year survival rate (47%) than those with OLA1 low expression (75%). OLA1 high expression was an independent factor of poor prognosis in CRC patients. OLA1-KO CRC cell lines showed lower ability of growth and tumorigenesis in vitro and in vivo. By mRNA sequence analysis, we found 113 differential express genes in OLA1-KO cell lines, of which 63 were hypoxic related. HIF1α was a key molecule in hypoxic regulation. Further molecular mechanisms showed HIF1α /CA9 mRNA and/or protein levels were heavily downregulated in OLA1-KO cell lines, which could explain the impaired tumorigenesis. According to previous studies, HIF1α was a downstream gene of GSK3β, we verified GSK3β was over-activated in OLA1-KO cell lines.
OLA1 was a new gene that was associated with carcinogenesis and poor outcomes in CRC by activation of HIF1α/CA9 axis, which may be interpreted by GSK3β.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
A phase-controlled ultralow-threshold phonon laser is proposed by using tunable optical amplifiers in coupled-cavity-optomechanical system. The multiplicative behavior of the individual enhancements, ...by engineering the phases and strengths of external parametric driving, makes it possible to achieve the strong-coupling regime of optomechanics, where the switching among radiation-pressure, parametric amplification, and three-mode optomechanical couplings can be realized and ultralow-threshold phonon lasing is observable. This opens up novel prospects for applications in, e.g. quantum acoustics, nonlinear phonon devices, and ultrasensitive motion sensing.
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