Photoelastic coupling in gallium arsenide optomechanical disk resonators

We analyze the magnitude of the radiation pressure and electrostrictive stresses exerted by light confined inside GaAs semiconductor WGM optomechanical disk resonators, through analytical and numerical means, and find the electrostrictive force to be of prime importance. We investigate the geometric and photoelastic optomechanical coupling resulting respectively from the deformation of the disk boundary and from the strain-induced refractive index changes in the material, for various mechanical modes of the disks. Photoelastic optomechanical coupling is shown to be a predominant coupling mechanism for certain disk dimensions and mechanical modes, leading to total coupling g$_{om}$ and g$_0$ reaching respectively 3 THz/nm and 4 MHz. Finally, we point towards ways to maximize the photoelastic coupling in GaAs disk resonators, and we provide some upper bounds for its value in various geometries

High frequency GaAs nano-optomechanical disk resonator

Optomechanical coupling between a mechanical oscillator and light trapped in a cavity increases when the coupling takes place in a reduced volume. Here we demonstrate a GaAs semiconductor optomechanical disk system where both optical and mechanical energy can be confined in a sub-micron scale interaction volume. We observe giant optomechanical coupling rate up to 100 GHz/nm involving picogram mass mechanical modes with frequency between 100 MHz and 1 GHz. The mechanical modes are singled-out measuring their dispersion as a function of disk geometry. Their Brownian motion is optically resolved with a sensitivity of 10^(-17)m/sqrt(Hz) at room temperature and pressure, approaching the quantum limit imprecision.Comment: 7 pages, 3 figure

Integrated AlGaAs source of highly indistinguishable and energy-time entangled photons

The generation of nonclassical states of light in miniature chips is a crucial step towards practical implementations of future quantum technologies. Semiconductor materials are ideal to achieve extremely compact and massively parallel systems and several platforms are currently under development. In this context, spontaneous parametric down conversion in AlGaAs devices combines the advantages of room temperature operation, possibility of electrical injection and emission in the telecom band. Here we report on a chip-based AlGaAs source, producing indistinguishable and energy-time entangled photons with a brightness of $7.2\times10^6$ pairs/s and a signal-to-noise ratio of $141\pm12$. Indistinguishability between the photons is demonstrated via a Hong-Ou-Mandel experiment with a visibility of $89\pm3\%$, while energy-time entanglement is tested via a Franson interferometer leading to a value for the Bell parameter $S=2.70\pm0.10$

Synthetic cannabinoid use in a case series of patients with psychosis presenting to acute psychiatric settings : Clinical presentation and management issues

Background: Novel Psychoactive Substances (NPS) are a heterogeneous class of synthetic molecules including synthetic cannabinoid receptor agonists (SCRAs). Psychosis is associated with SCRAs use. There is limited knowledge regarding the structured assessment and psychometric evaluation of clinical presentations, analytical toxicology and clinical management plans of patients presenting with psychosis and SCRAs misuse. Methods: We gathered information regarding the clinical presentations, toxicology and care plans of patients with psychosis and SCRAs misuse admitted to inpatients services. Clinical presentations were assessed using the PANSS scale. Vital signs data were collected using the National Early Warning Signs tool. Analytic chemistry data were collected using urine drug screening tests for traditional psychoactive substances and NPS. Results: We described the clinical presentation and management plan of four patients with psychosis and misuse of SCRAs. Conclusion: The formulation of an informed clinical management plan requires a structured assessment, identification of the index NPS, pharmacological interventions, increases in nursing observations, changes to leave status and monitoring of the vital signs. The objective from using these interventions is to maintain stable physical health whilst rapidly improving the altered mental state.Peer reviewedFinal Published versio

The Management of Psychomotor Agitation Associated with Schizophrenia or Bipolar Disorder. A Brief Review

The early and correct assessment of psychomotor agitation (PMA) is essential to ensure prompt intervention by healthcare professionals to improve the patient's condition, protect healthcare staff, and facilitate future management. Proper training for recognizing and managing agitation in all care settings is desirable to improve patient outcomes. The best approach is one that is ethical, non-invasive, and respectful of the patient's dignity. When deemed necessary, pharmacological interventions must be administered rapidly and avoid producing an excessive state of sedation, except in cases of severe and imminent danger to the patient or others. The purpose of this brief review is to raise awareness about best practices for the management of PMA in emergency care situations and consider the role of new pharmacological interventions in patients with agitation associated with bipolar disorder or schizophrenia

The Management of Psychomotor Agitation Associated with Schizophrenia or Bipolar Disorder: A Brief Review

The early and correct assessment of psychomotor agitation (PMA) is essential to ensure prompt intervention by healthcare professionals to improve the patient’s condition, protect healthcare staff, and facilitate future management. Proper training for recognizing and managing agitation in all care settings is desirable to improve patient outcomes. The best approach is one that is ethical, non-invasive, and respectful of the patient’s dignity. When deemed necessary, pharmacological interventions must be administered rapidly and avoid producing an excessive state of sedation, except in cases of severe and imminent danger to the patient or others. The purpose of this brief review is to raise awareness about best practices for the management of PMA in emergency care situations and consider the role of new pharmacological interventions in patients with agitation associated with bipolar disorder or schizophrenia

Wavelength-sized GaAs optomechanical resonators with GHz frequency

We report on wavelength-sized GaAs optomechanical disk resonators showing ultra-strong optomechanical interaction. We observe optical transduction of a disk mechanical breathing mode with 1.4 GHz frequency and effective mass of ~ 2 pg. The measured vacuum optomechanical coupling rate reaches 0.8 MHz, with a related differential optomechanical coupling factor of 485 GHz/nm. The disk Brownian motion is optically resolved with a sensitivity of 10-17 m/{\sqrt}Hz at room temperature and pressure.Comment: 8 pages, 3 figure

Mapping Regions of Provenance for Italy

In the follow-up of 1999/105/CE Directive on national level, the new map of regions of provenance for forest reproductive materials of Italy is adopted as reference for the national register of forest basic materials. The new map was outlined to match needs linked to the transposition of European legislation to the complexity of the Peninsula’s environment and the national nursery system. The main objective in this technical note is to present the map units in relation to the distribution of main forest species. The map units of ecoregional meaning might facilitate new allocations for forest reproductive materials which are needed to increase genetic diversity. Furthermore, studies on genetic variability of forest species are required to understand the possible interactions between the ecological amplitude of forest species, their actual genetic diversity, and possible adaptation to future climate conditions