Search

Optical sources that deterministically produce single photons with a high suppression of multi-photon emission and a negligible background component are promising candidates for standard sources for quantum metrology, quantum communication and foundations of quantum mechanics. In this paper, the photon number distribution of non-classical light emitted by nitrogen vacancy (NV) centres in nano-diamonds is studied by three different experimental techniques. The photon number resolving transition edge sensor (TES) detector and the On/Off detection method are applied to determine the diagonal elements of the optical density matrix. From the data measured by the two methods the second order correlation function at time delay zero is calculated and compared with the g2(0)-values obtained by Hanbury Brown?Twiss (HBT) interferometric measurements. Among the g2(0)-values evaluated with the three techniques, we found good agreement in the results for a single photon emitter with a g2(0)-value close to zero and a multi-photon source with a g2(0)-value of approximately 0.5.

In this work we report on the optical investigation of Zn doped GaN films fabricated by metal organic chemical vapor deposition. The samples show bright emission in the blue spectral range around 2.9 eV when Si codoping is provided. This emission is suggested to be used for single-photon emission, thus the density of the Zn-Si pairs was drastically reduced leading to a decrease of the blue luminescence. For electrically excited single-photon sources these Zn-Si pairs have to be incorporated into LEDs, therefore we fabricated GaN-based nano-LEDs which show electroluminescence at 430 nm (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

A widespread use of various relative calibration techniques is established in order to realize reliable and low uncertainty measurements of the detection efficiency, which is one key parameter characterizing single photon detectors. In the following paper we will present an approach to evaluate the relative detection efficiency of single photon avalanche photo diode (SPAD) detectors compared to a standard detector. This calibration technique is based upon the fiber-coupled relative efficiency calibration of analogue detectors, used in fiber-optic communication. For the first time, to our knowledge, an intrinsic single photon source based on the nitrogen-vacancy center in diamond was used for this purpose. Furthermore, the possible influence of different photon statistics, arising from different irradiation sources like thermal sources or lasers on the calibration results for the fiber exchange method has been theoretically studied.

Das Ziel dieser Studie war die klinische Evaluation von Patienten mit Tieftonrestgehor, die fur die kombinierte, ipsilaterale elektrisch akustische Stimulation (EAS) des auditorischen Systems mit einem Kochleaimplantat versorgt wurden. 18 Patienten mit Tieftonrestgehor wurden mit einem MED-EL-Combi-40+-Kochleaimplantat versorgt. Eine modifizierte chirurgische Implantationstechnik zum Erhalt des Restgehors wurde bei allen Patienten angewandt. Die Elektrodeneinfuhrtiefe betrug 18–22 mm (360°). Reintonaudiometrische Schwellen wurden pra- und postoperativ gemessen. Umfangreiche sprachaudiometrische Untersuchungen wurden an 2 Patienten durchgefuhrt. Bei 16 von 18 Patienten (88,9%) konnte das Restgehor zumindest teilweise erhalten werden. Ein kompletter Erhalt des Restgehors war in 7 Fallen (38,9%), und ein partieller Horerhalt bei 9 Patienten (50,0%) moglich. Sprachaudiometrische Untersuchungen bei 2 Patienten mit Langzeiterfahrungen zeigen einen synergistischen Effekt fur die kombinierte, ipsilaterale elektrisch-akustische Stimulation gegenuber der alleinigen elektrischen Stimulation mit dem Kochleaimplantat. Bei Verwendung einer atraumatischen Implantationstechnik kann bei einer Einfuhrtiefe von 18–22 mm (360°) der MED-EL-Elektrode das Tieftonrestgehor mit groser Wahrscheinlichkeit erhalten werden. Sprachdiskriminationstests zeigen einen synergistischen Effekt der kombinierten elektrisch-akustischen Stimulation, vor allem im Storschall. Durch eine 360°-Insertion wird eine vollwertige Implantatfunktion erreicht. Mit dem Kochleaimplantat allein zeigten die EAS-Patienten Sprachdiskriminationswerte, die uber dem Durchschnitt von regular implantierten Kochleaimplantatpatienten liegen.

BACKGROUND Tissue microarrays (TMAs) are still seldom used in oncological research, especially that involving otorhinolaryngology, although the benefit of this method has often been reported. METHODS We prepared ten different tumor probes from patients with head and neck cancer for immunohistochemistry and performed ki67 and proliferating cell nuclear antigen (PCNA) staining on the usual paraffin sections as well as on TMAs consisting of the same tissue. RESULTS AND CONCLUSIONS We conclude that investigation by means of TMA makes oncological research, and especially the screening of tumor probes, much more efficient since a high correlation ( r>0.7, P

We present some Quantum Tomography related results recently obtained in the Quantum Optics labs of the National Institute of Metrological Research (INRIM). Initially we describe the first experimental implementation of a new protocol for the reconstruction of a photon-number-resolving (PNR) detector’s POVM (Positive Operator-Valued Measure): such a protocol, exploiting the strong quantum correlations of an ancillary state, results more robust and efficient than its classical counterparts. The second part of the paper focuses on the quantum characterization of a transition-edge sensor (TES) based PNR detector, i.e. the experimental tomography of the POVM of a TES, with a method based on a quorum of coherent probes: we show the reconstruction of the POVM elements up to 11 detected photons and 100 incoming photons, demonstrating the linearity of such a device. Finally, we present a method for the experimental reconstruction of the modal structure of multimode optical fields exploiting a single measurement of higher-order photon number autocorrelation functions. We show our reconstructions of up to three different modes per optical state, demonstrating the excellent agreement with the theoretical predictions and the robustness of our method itself.

We present a simple method to reconstruct the mode distribution of multimode classical and nonclassical optical fields using a single measurement of higher-order photon number correlation functions. Knowing the underlying number and structure of occupied modes of a light field plays a crucial role in minimizing loss and decoherence of quantum information. Typically, full characterization of the mode structure involves a series of several separate measurements in spatial, temporal, frequency, and polarization domains. We experimentally demonstrate reconstruction of up to three modes with excellent agreement and study the robustness of our method in experimentally realizable regimes.

We report on the single photon emission of bunched NV-centres by focusing on different spatial fractions of the emission spot, which shows that g(2)(0)

Over the past ten years an increasing interest for improved single photon technology has been come up in research fields as diverse as optical quantum information technology, laser ranging, remote sensing, astronomy or biomedical imaging. In this context metrological validation of single photon sources and detectors are expected to have an immediate impact on further industrial needs of prospective standards and certifications from national metrology institutes (NMIs). Worldwide research programs for absolute single photon detector calibration exist at several NMIs, preferably dealing with parametric down-conversion [1]. Despite of this, a widespread use of various relative calibration techniques is established in order to realise reliable and low uncertainty measurements of the detection efficiency, which is one key parameter characterising single photon detectors.

To evaluate the possibility of preservation of low-frequency hearing in atraumatic cochlear implant electrode insertion procedures for combined, ipsilateral electric and acoustic stimulation.A total of 21 patients were implanted with a MED EL C40+ cochlear implant using an atraumatic electrode insertion technique to preserve residual low-frequency hearing. Pure-tone audiometric thresholds were measured pre- and postoperatively to evaluate the degree of preserved hearing. Speech discrimination tests in quiet and with background noise were performed in a patient with successful hearing preservation.Using the atraumatic electrode insertion procedure with an insertion depth of 360 degrees (18-24 mm), hearing preservation could be achieved in 18/21 patients (85.7%). Three patients (14.3%) lost their residual low-frequency hearing after the implantation. Residual hearing was preserved completely in 13 patients (61.9%) and partial hearing preservation was possible in 5 (23.8%). Preliminary speech discrimination tests showed a dramatic benefit for the combined electric and acoustic stimulation mode compared to cochlear implantation alone.Preservation of low-frequency hearing in cochlear implantation is possible in patients implanted because of profound high-frequency deafness. With the development of new, more atraumatic electrode designs, preservation of residual hearing should be further improved.

Recent studies on polychemotherapy of head and neck cancer showed an improved remission rate on adding taxanes to the standard cytotoxic drugs cisplatin and 5-fluorouracil (5-FU). Moreover, for enha

Objectives: Evaluation was made of eosinophilic cationic protein (ECP) in nasal secretion for measuring the degree of nasal inflammation and monitoring response to therapy in cystic fibrosis (CF) patients with chronic rhinosinusitis. Symptoms and findings in regard to ECP levels before and after treatment were described. Study Design: Study was prospective, with 21 CF patients aged 4 to 19 years; 20 healthy volunteers served as controls. Collection of nasal secretion by a sponge was performed, and blood samples were obtained for serum. Cystic fibrosis (CF) patients were classified according to nasal symptoms and findings. Methods: ECP was measured by fluoro-immunoassay. Age, sex, nasal symptoms, and endoscopic and histological findings were obtained, and examinations were conducted before and after treatment ; recurrences were recorded. Results: In CF patients with chronic nasal inflammation, increased nasal levels of ECP were detected when compared with asymptomatic CF patients or healthy nonatopic subjects. ECP concentrations were strongly related to the extent of nasal disease; patients with nasal polyps had higher levels than those without. Checked at 1 and 4 months after treatment, ECP levels declined with regression of symptoms, and in patients with exacerbation of nasal disease, ECP levels rose. Conclusions: According to our study, there is a relationship between levels of ECP in nasal secretions and the degrees of nasal inflammation. In addition, the measurement of ECP could be useful in monitoring nasal disease in CF patients.

Knowing the mode structure of light aids in minimizing loss and decoherence of quantum information. We present and experimentally implement reconstruction of the mode distributions of classical and non-classical light using measured photon number distributions.