Search

The negative impact of adverse experiences in childhood on neurodevelopment is well documented. Less attention however has been given to the impact of variations in "normative" parenting behaviors. The influence of these parenting behaviors is likely to be marked during periods of rapid brain reorganization, such as late childhood. The aim of the current study was to investigate associations between normative parenting behaviors and the development of structural brain networks across late childhood. Data were collected from a longitudinal sample of 114 mother-child dyads (54% female children, M age 8.41 years, SD = 0.32 years), recruited from low socioeconomic areas of Melbourne, Australia. At the first assessment parenting behaviors were coded from two lab-based interaction tasks and structural magnetic resonance imaging (MRI) scans of the children were performed. At the second assessment, approximately 18 months later (M age 9.97 years, SD = 0.37 years) MRI scans were repeated. Cortical thickness (CT) was extracted from T1-weighted images using FreeSurfer. Structural covariance (SC) networks were constructed from partial correlations of CT estimates between brain regions and estimates of network efficiency and modularity were obtained for each time point. The change in these network measures, from Time 1 to Time 2, was also calculated. At Time 2, less positive maternal affective behavior was associated with higher modularity (more segregated networks), while negative maternal affective behavior was not related. No support was found for an association between local or global efficacy and maternal affective behaviors at Time 2. Similarly, no support was demonstrated for associations between maternal affective behaviors and change in network efficiency and modularity, from Time 1 to Time 2. These results indicate that normative variations in parenting may influence the development of structural brain networks in late childhood and extend current knowledge about envir

To grasp a greater understanding and explore the various quantum technologies, it is imperative to efficiently fabricate a single crystalline material that can host bright point defects. Point defects or single photon sources are necessary to push the boundaries for quantum technologies, specifically, quantum telecommunications and quantum computing. This endeavor has led to several 1D, 2D and 3D platforms to be explored to test their applicability for the generation of pure single photon emitters (SPE). One of these platforms include diamond due to its wide bandgap and ability to host a variety of photostable, optically active group IV SPE defects at room temperature. Several diamond defects have been studied extensively, including the Nitrogen vacancy (NV), Silicon vacancy (SiV) and, recently, the Germanium vacancy (GeV) color centers and have all shown to be stable SPEs at room temperature. In addition to be an optically active single photon source, the defect additionally requires the ability to be electrically excited. Electrically pumping SPEs is highly desired for optoelectronic applications. These properties of diamond have led to several publications on the fabrication and characterization of optically and electrically excited 3D devices fabricated from diamond. This chapter delves into the fabrication of nanoscale, high aspect ratio conductive diamond membranes that can host group IV color centers. These structures demonstrate several key advantages which include scaling of emitter creation and ease of transfer between substrates.

Diamond is a material of choice in the pursuit of integrated quantum photonic technologies. So far, the majority of photonic devices fabricated from diamond are made from (100)‐oriented crystals. In this work, we demonstrate a methodology for the fabrication of optically active membranes from (111)‐oriented diamond. We use a liftoff technique to generate membranes, followed by chemical vapor deposition of diamond in the presence of silicon to generate homogenous silicon vacancy color centers with emission properties that are superior to those in (100)‐oriented diamond. We further use the diamond membranes to fabricate microring resonators with quality factors exceeding ~ 3000. Supported by finite‐difference time‐domain calculations, we discuss the advantages of (111)‐oriented structures as building blocks for quantum nanophotonic devices.

© 2019 American Physical Society. We realize a potential platform for an efficient spin-photon interface, namely negatively-charged silicon-vacancy centers in a diamond membrane coupled to the mode of a fully-tunable, fiber-based, optical resonator. We demonstrate that introducing the thin (∼200nm), single crystal diamond membrane into the mode of the resonator does not change the cavity properties, which is one of the crucial points for an efficient spin-photon interface. In particular, we observe constantly high Finesse values of up to 3000 and a linear dispersion in the presence of the membrane. We observe cavity-coupled fluorescence from an ensemble of SiV- centers with an enhancement factor of ∼1.9. Furthermore from our investigations we extract the ensemble absorption and extrapolate an absorption cross section of (2.9±2)×10-12cm2 for a single SiV- center, much higher than previously reported.

© 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement. Color centers in diamond have garnered significant attention for applications in integrated quantum photonics. The availability of thin (~ hundred of nanometers) diamond membranes is paramount to achieve this goal. In this paper, we describe in detail a robust, reproducible and cost effective fabrication method that enables engineering high quality thin diamond membranes with uniform distribution of germanium vacancies employing microwave plasma chemical vapor deposition. We use a combination of different germanium precursors for homogeneous doping of the membranes to increase the probability of germanium incorporation into the diamond lattice. Our fabrication methodology can be further extended to implementation of other color centers in thin diamond membranes and be used for engineering quantum photonic devices.