Unidirectional Lasing Emerging from Frozen Light in Non-Reciprocal Cavities

We introduce a class of unidirectional lasing modes associated with the frozen mode regime of non-reciprocal slow-wave structures. Such asymmetric modes can only exist in cavities with broken time-reversal and space inversion symmetries. Their lasing frequency coincides with a spectral stationary inflection point of the underlying passive structure and is virtually independent of its size. These unidirectional lasers can be indispensable components of photonic integrated circuitry.Comment: 5 pages, 3 figure

Does time equal vision in the acute treatment of a cohort of AQP4 and MOG optic neuritis?

Objective To investigate whether visual disability which is known to accumulate by poor recovery from optic neuritis (ON) attacks can be lessened by early treatment, we investigated whether the time from symptom onset to high-dose IV methylprednisolone (IVMP) affected visual recovery. Methods: A retrospective study was performed in a consecutive cohort of patients following their first aquaporin-4 (AQP4)-IgG or myelin oligodendrocyte glycoprotein (MOG)-IgG-ON. Best-corrected visual acuity (BCVA) in ON eyes at 3 months (BCVA3mo) was correlated with time to IVMP (days). In cases of bilateral ON, 1 eye was randomly selected. Results: A total of 29 of 37 patients had ON (27 AQP4-seropositive neuromyelitis optica spectrum disorder [NMOSD] and 9 MOG-IgG-ON), 2 of whom refused treatment. Of the 27 patients included, 10 presented later than 7 days from onset. The median BCVA3mo of patients treated >7 days was 20/100 (interquartile range 20/100–20/200). Patients treated >7 days had an OR of 5.50 (95% CI 0.88–34.46, p = 0.051) of failure to regain 0.0 logMAR vision (20/20) and an OR of 10.0 (95% CI 1.39–71.9) of failure to regain 0.2 logMAR vision (20/30) (p = 0.01) compared with patients treated within 7 days. ROC analysis revealed that the optimal criterion of delay in IVMP initiation was ≤4 days, with a sensitivity and specificity of 71.4% and 76.9%, respectively. Conclusions: In this retrospective study of ON with AQP4 and MOG-IgG, even a 7-day delay in IVMP initiation was detrimental to vision. These results highlight the importance of early treatment for the long-term visual recovery in this group of patients. A prospective, multicenter study of the effects of timing of IVMP is currently underway. Classification of evidence: This study provides Class IV evidence that hyperacute treatment of AQP4 and MOG-ON with IVMP increases the chance for good visual recovery (20/20 vision) and that even a greater than 7-day delay in treatment is associated with a higher risk for poor visual recovery

Effect of Oblique Light Incidence on Magnetooptical Properties of One-Dimensional Photonic Crystals

We have investigated the magnetooptical properties of one-dimensional magnetic photonic crystals for the case of oblique light incidence. We developed a theoretical model based on the transfer matrix approach. We found several new effects such as transmittance resonance peak shift versus external magnetic field and the Faraday effect dependence on the incidence angle.We discuss several possible one-dimensional magnetic photonic crystals applications for the optical devices

Controlled Dephasing of Electrons by Non-Gaussian Shot Noise

In a 'controlled dephasing' experiment [1-3], an interferometer loses its coherence due to entanglement with a controlled quantum system ('which path' detector). In experiments that were conducted thus far in mesoscopic systems only partial dephasing was achieved. This was due to weak interactions between many detector electrons and the interfering electron, resulting in a Gaussian phase randomizing process [4-10]. Here, we report the opposite extreme: a complete destruction of the interference via strong phase randomization only by a few electrons in the detector. The realization was based on interfering edge channels (in the integer quantum Hall effect regime, filling factor 2) in a Mach-Zehnder electronic interferometer, with an inner edge channel serving as a detector. Unexpectedly, the visibility quenched in a periodic lobe-type form as the detector current increased; namely, it periodically decreased as the detector current, and thus the detector's efficiency, increased. Moreover, the visibility had a V-shape dependence on the partitioning of the detector current, and not the expected dependence on the second moment of the shot noise, T(1-T), with T the partitioning. We ascribe these unexpected features to the strong detector-interferometer coupling, allowing only 1-3 electrons in the detector to fully dephase the interfering electron. Consequently, in this work we explored the non-Gaussian nature of noise [11], namely, the direct effect of the shot noise full counting statistics [12-15].Comment: 14 pages, 4 figure

Low-temperature tapered-fiber probing of diamond NV ensembles coupled to GaP microcavities

In this work we present a platform for testing the device performance of a cavity-emitter system, using an ensemble of emitters and a tapered optical fiber. This method provides high-contrast spectra of the cavity modes, selective detection of emitters coupled to the cavity, and an estimate of the device performance in the single- emitter case. Using nitrogen-vacancy (NV) centers in diamond and a GaP optical microcavity, we are able to tune the cavity onto the NV resonance at 10 K, couple the cavity-coupled emission to a tapered fiber, and measure the fiber-coupled NV spontaneous emission decay. Theoretically we show that the fiber-coupled average Purcell factor is 2-3 times greater than that of free-space collection; although due to ensemble averaging it is still a factor of 3 less than the Purcell factor of a single, ideally placed center.Comment: 15 pages, 6 figure

Dephasing and Measurement Efficiency via a Quantum Dot Detector

We study charge detection and controlled dephasing of a mesoscopic system via a quantum dot detector (QDD), where the mesoscopic system and the QDD are capacitively coupled. The QDD is considered to have coherent resonant tunnelling via a single level. It is found that the dephasing rate is proportional to the square of the conductance of the QDD for the Breit-Wigner model, showing that the dephasing is completely different from the shot noise of the detector. The measurement rate, on the other hand, shows a dip near the resonance. Our findings are peculiar especially for a symmetric detector in the following aspect: The dephasing rate is maximum at resonance of the QDD where the detector conductance is insensitive to the charge state of the mesoscopic system. As a result, the efficiency of the detector shows a dip and vanishes at resonance, in contrast to the single-channel symmetric non-resonant detector that has always a maximum efficiency. We find that this difference originates from a very general property of the scattering matrix: The abrupt phase change exists in the scattering amplitudes in the presence of the symmetry, which is insensitive to the detector current but {\em stores} the information of the quantum state of the mesoscopic system.Comment: 7 pages, 3 figure

Practical recognition tools of immunoglobulin G serum antibodies against the myelin oligodendrocyte glycoprotein‐positive optic neuritis and its clinical implications

Myelin oligodendrocyte glycoprotein (MOG)‐associated disease is an autoimmune disease of the central nervous system, associated with the presence of immunoglobulin G serum antibodies against MOG. Recent data have allowed characterization of the clinical spectrum of MOG‐associated disease, which is now considered a new disease entity, distinct from multiple sclerosis and neuromyelitis optica spectrum disorders. Optic neuritis is the most common clinical presentation of MOG‐associated disease in adults, both at disease onset and during the disease course, and has several distinct clinical and paraclinical features. Immunoglobulin G serum antibodies against MOG‐positive optic neuritis is often bilateral and associated with optic disc swelling and a longitudinally extensive abnormal magnetic resonance imaging signal involving the retrobulbar portion of the optic nerve. The visual acuity during the acute attack is severely decreased, and the response to corticosteroids is often rapid and prominent. However, early relapses after steroid cessation are common, and a subset of patients is left with a permanent visual disability. In this review, we discuss the clinical and paraclinical features of immunoglobulin G serum antibodies against MOG‐positive optic neuritis in adults, and focus on the distinctive features that can enable its early diagnosis. Therapeutical considerations at the acute stage and for relapse prevention are further deliberated

Features of the functional activity of macrophage link of immunity with gastroesophageal reflux disease depending on the type of reluctate: in vitro model

Aim. A generalized analysis of changes in functional activity of macrophages on the basis of phagocytic activity, cytokine profile, changes in the level of expression of surface markers characteristic of pro - or anti-inflammatory phenotype of the cells when exposed to reluctate. Materials and methods. Developed in vitro model of co-peritoneal macrophages of mice With57/BL6 (n=65) and reluctate patients with gastroesophageal reflux disease (GERD; n=65) having different pH values (three group comparison). Took into account the standard criteria phagocytic ability (absorption Staphylococcus aureus 9198, light microscopy), secretory activity (cytokine profile Th1/Th2, flow cytometry) and receptor characterization of macrophages (expression of CD25/80/163/206, flow cytometry). Results. The phagocytic activity of macrophages, calculated on the basis of the average number of bacteria ingested by one phagocyte, is not associated with the pH value of the added reluctate. It is established that the alkalinisation of reluctate leads to significant alteration in the expression of CD receptors - decrease M1 and increase M2. The index of total production of Th1/Тһ2 in groups progressively decreased with increasing pH of reluctate and amounted to 3.6 units in the group pH from 4.6 to 6.6; 2.8 units group a pH of 6.7-7.2 and 1.6 units in the group pH of 7.3 to 8.1, due to increased production of Th2 cytokines at offset reluctate pH to slightly alkaline side. The data obtained indicate the increase of expression and secretion of anti-inflammatory markers at an alkaline pH shift of reluctate. Analysis of the studied characteristics of the activity profile of macrophages in the proposed in vitro model justifies the need for considering the peculiarities of the functional activity of macrophages under the influence of reluctate different nature. The special importance of studying the cytokine profile and characteristics of the functional activity of macrophages in patients with GERD, given the nature of reluctate