Effect of hole-shape irregularities on photonic crystal waveguides

The effect of irregular hole shape on the spectrum and radiation losses of a photonic crystal waveguide is studied using Bloch-mode expansion. Deviations from a perfectly circular hole are characterized by a radius fluctuation amplitude and correlation angle. It is found that the parameter which determines the magnitude of the effect of disorder is the standard deviation of the hole areas. Hence, for a fixed amplitude of the radius fluctuation around the hole, those effects are strongly dependent on the correlation angle of the irregular shape. This result suggests routes to potentially improve the quality of photonic crystal structures.Comment: 3 pages, 3 figure

Drenagem precoce de abscesso tubo-ovariano guiada por ultrassonografia ou terapia conservadora : análise comparativa entre desfechos

Introdução: Os abscessos tubo-ovarianos (ATOS) são importantes causas de morbidade feminina. O tratamento habitual é baseado em antibioticoterapia isolada ou associada a abordagem invasiva. No entanto, os procedimentos invasivos guiados por imagem, representam uma possibilidade de manejo desta patologia. Objetivo: Realizar uma análise comparativa entre o prognóstico de pacientes tratadas com tratamento clínico padrão (antibioticoterapia) versus pacientes que foram submetidas a drenagem primária guiada por ultrassonografia, associada também a antibioticoterapia, analisando o tempo de permanência hospitalar e os desfechos de morbimortalidade, como melhora clínica e laboratorial, complicações, necessidade de (re)intervenção, reinternação e morte. Método: Foi realizado um estudo observacional de coorte retrospectiva, através da revisão de prontuários de pacientes com diagnósticos de Doença Inflamatória Pélvica (DIP) e ATO, conforme CID, registrados entre os meses de janeiro de 2017 a julho de 2022 no Hospital Fêmina. O grupo de controle foi representado pelas pacientes que receberam apenas tratamento com antibioticoterapia endovenosa. Já no grupo dos casos estão pacientes que além da antibioticoterapia padrão foram submetidas a punção guiada por ultrassonografia transvaginal. Os dados foram digitados em planilha Excel e exportados para o programa SPSS v. 20.0. Valores de P <0,05 foram considerados indicativos de significância estatística. Resultados: Dos 113 pacientes do estudo, 50 (44%) mulheres foram tratadas isoladamente com antibióticos, 21 (18%) foram submetidos a drenagem precoce em menos de 72 horas da admissão e 42 (37%) submetidas a drenagem guiada após esse período. Não houve diferença estatisticamente significativa no tempo de permanência hospitalar entre os grupos simultaneamente, sendo em média de 6,4 dias nos controles e de 5,1 dias no grupo de drenagem precoce, e de 9,6 dias no grupo de drenagens tardias de (p=0,290). Houve redução de em média 2,9 dias de permanência hospitalar ((IC 95% (-4,8 a -0,9) (p=0,04)) no grupo da drenagem precoce (<72 horas) em relação aos controles. A melhora clínica precoce (p= 0,012) e a queda esperada da PCR (p= 0,033) foram mais frequentes nas pacientes submetidas à drenagem. O tempo de permanência hospitalar aumenta com o diâmetro do abscesso: 0,4 ((IC 95% 0,1 – 0,7) (p= 0,05)) dias a cada centímetro, independentemente das outras variáveis. Conclusão: A drenagem guiada por ultrassom de abscessos é uma técnica de sucesso, com mínimas complicações relacionadas ao procedimento, acelerando a melhora clínica e laboratorial das pacientes e reduzindo o tempo de internação quando realizada precocemente, idealmente em até 72 horas da admissão.Introduction: Tubo-ovarian abscesses (ATOS) are important causes of increased female morbidity. The usual treatment is based on antibiotic therapy or a surgical approach. However, invasive image-guided procedures are an alternative treatment for this pathology. Objective: To perform a comparative analysis between the morbidity outcomes and the prognosis of patients treated with standard clinical treatment (broad spectrum antibiotic therapy) versus patients treated with early ultrasound-guided drainage, also associated with antibiotic therapy. Method: A longitudinal study was carried out, with a concurrent design through the review of medical records of patients with diagnoses of DIP and ACT, according to the ICD, registered between the months of January 2017 to December 2021 at Hospital Femina. The standard group included patients who received only treatment with intravenous antibiotic therapy. In the control group, there were patients who, in addition to standard antibiotic therapy, underwent transvaginal ultrasound-guided puncture. The data will be entered into an Excel spreadsheet and later exported to the SPSS v program. 20.0. Two-sided P values <0.05 were considered indications of statistical significance. Results: Of the 113 patients in the study, 50 (44%) women were treated alone with antibiotics, 21 (18%) underwent early drainage within 72 hours of admission, and 42 (37%) underwent guided drainage after this period. There was no statistically significant difference in the length of hospital stay between the groups simultaneously, with an average of 6.4 days in the controls and 5.1 days in the early drainage group, and 9.6 days in the late drainage group (p=0.290). There was an average reduction of 2.9 days of hospital stay ((CI 95% (-4.8 to -0.9) (p=0.04)) in the early drainage group (<72 hours) compared to controls. Early clinical improvement (p= 0.012) and expected drop in CRP (p= 0.033) were more frequent in patients who underwent drainage. Length of hospital stay increases with abscess diameter: 0.4 ((95% CI 0.1 – 0.7) (p= 0.05)) days per centimeter, regardless of other variables. Conclusion: Ultrasound-guided drainage of abscesses is a highly successful technique, with minimal procedure-related complications, with brief clinical and laboratory improvement of the patients, as well as a reduction in the length of hospital stay provided it is performed early, ideally within 72 hours of admission

Highly indistinguishable single photons from incoherently and coherently excited GaAs quantum dots

Semiconductor quantum dots are converging towards the demanding requirements of photonic quantum technologies. Among different systems, quantum dots with dimensions exceeding the free-exciton Bohr radius are appealing because of their high oscillator strengths. While this property has received much attention in the context of cavity quantum electrodynamics, little is known about the degree of indistinguishability of single photons consecutively emitted by such dots and on the proper excitation schemes to achieve high indistinguishability. A prominent example is represented by GaAs quantum dots obtained by local droplet etching, which recently outperformed other systems as triggered sources of entangled photon pairs. On these dots, we compare different single-photon excitation mechanisms, and we find (i) a "phonon bottleneck" and poor indistinguishability for conventional excitation via excited states and (ii) photon indistinguishablilities above 90% for both strictly resonant and for incoherent acoustic- and optical-phonon-assisted excitation. Among the excitation schemes, optical phonon-assisted excitation enables straightforward laser rejection without a compromise on the source brightness together with a high photon indistinguishability

Cavity-Enhanced Two-Photon Interference using Remote Quantum Dot Sources

Quantum dots in cavities have been shown to be very bright sources of indistinguishable single photons. Yet the quantum interference between two bright quantum dot sources, a critical step for photon based quantum computation, has never been investigated. Here we report on such a measurement, taking advantage of a deterministic fabrication of the devices. We show that cavity quantum electrodynamics can efficiently improve the quantum interference between remote quantum dot sources: poorly indistinguishable photons can still interfere with good contrast with high quality photons emitted by a source in the strong Purcell regime. Our measurements and calculations show that cavity quantum electrodynamics is a powerful tool for interconnecting several devices.Comment: 5 pages, 4 figures (Supp. Mat. attached

Tuning emission energy and fine structure splitting in quantum dots emitting in the telecom O-band

We report on optical investigations of MOVPE-grown InGaAs/GaAs quantum dots emitting at the telecom O-band that were integrated onto uniaxial piezoelectric actuators. This promising technique, which does not degrade the emission brightness of the quantum emitters, enables us to tune the quantum dot emission wavelengths and their fine-structure splitting. By spectrally analyzing the emitted light with respect to its polarization, we are able to demonstrate the cancelation of the fine structure splitting within the experimental resolution limit. This work represents an important step towards the high-yield generation of entangled photon pairs at telecommunication wavelength, together with the capability to precisely tune the emission to target wavelengths

First-principles method for high-QQ photonic crystal cavity mode calculations

We present a first-principles method to compute radiation properties of ultra-high quality factor photonic crystal cavities. Our Frequency-domain Approach for Radiation (FAR) can compute the far-field radiation pattern and quality factor of cavity modes $\sim 100$ times more rapidly than conventional finite-difference time domain calculations. It also provides a simple rule for engineering the cavity's far-field radiation pattern