Electronically tunable silicon photonic delay lines

Electronically tunable optical true-time delay lines are proposed. The devices utilize the combination of apodised gratings and the free-carrier plasma effect to tune the enhanced delay of silicon waveguides at a fixed wavelength. Three variations of the proposed scheme are studied and compared. The compact and integrable devices can achieve tuning ranges as high as similar to 660 ps with a loss of \u3c 2.2 dB when operated in the reflection mode of the gratings. A delay of similar to 40 ps with a loss of \u3c 10 dB and an estimated operation bit rate of similar to 20 Gb/s can be achieved

The effect of bilingualism on the processing of clustering and switching in verbal fluency tasks

Background: This study examined the effect of bilingualism on the processing of clustering and switching in verbal fluency tasks in Farsi-Balochi bilinguals. Methods: Ninety participants entered this study, including 45 Farsi monolinguals and 45 Farsi-Balochi bilinguals. All participants were male university students between the ages of 18 to 24 years. Verbal fluency tests were performed and the clustering and switching scores were calculated. Data was analyzed in SPSS-16 software. Results: The monolingual group obtained a score of 32.84 in the total semantic fluency task and 24.13 in the phonemic fluency task, while the bilingual group obtained 30.70 in the semantic task and 29.37 in the phonemic task. The number of switches between the clusters and the mean cluster size were 35.82 and 2.6 in the monolingual group and 38.65 and 2.26 in the bilingual group, respectively. The difference between groups in phonemic fluency, phonemic switching, and semantic clustering was significant (p˂0.05). Discussion: The bilingual group performed better in phonemic fluency and switched more between the clusters. Meanwhile, the monolinguals produced more words in each cluster than the bilinguals

Comparison of Psychopathologic Characteristics between Individuals Undergoing Methadone Maintenance Treatment, Opioid Dependents, and Control Group

Background: Methadone maintenance treatment (MMT) can theoretically reduce the psychosocial harms of opioid dependency. The increasing number of MMT clinics in Iran during the last two decades was not accompanied by a reduction in addiction rates. Therefore, this study was conducted to compare the psychopathological characteristics of individuals on MMT, opioid dependents, and a control group in the Iranian population. Methods: This cross-sectional study was conducted in Mashhad to evaluate the psychopathological profile of 99 participants (33 opioid-dependent individuals [ODI], 33 MMT clients, and 33 controls) using the Symptom Checklist-90-Revised (SCL-90-R) questionnaire and demographic form. Parametric and non-parametric tests were used to compare the mean score of symptoms between the three groups. The Spearman correlation test was used to test the correlation of psychological features with age anddependency duration.  Findings: There was no significant difference between MMT clients and ODI regarding the Global Severity Index (GSI) and nine items of the SCL-90-R questionnaire. However, a significant difference was found between the controls and two other groups (P<0.001). Paranoid ideation in the ODI was more frequent compared to MMT clients significantly (P=0.015). Psychological characteristics had a direct correlation with dependency duration and an inverse correlation with age (P<0.05). Conclusion: Psychopathologic features observed in the dependent patients and MMT clients were significantly higher than in the control group. It seems that the psychopathology profile in MMT clients was not better than dependent individuals in Ira

Integrated Nanophotonic Devices in Lithium Niobate

Lithium niobate (LN) is a ferroelectric crystal offering a broad transparency spectrum, together with excellent electro-optic and nonlinear optical properties. Thanks to them, LN is setting the standard for quantum optics and telecommunications in critical applications such as ultrafast modulation and frequency conversion. The development of a reliable nanophotonic platform in LN can be expected to effectively leverage all such appealing functionalities in compact and integrated formats and provide important and complementary functionalities to current silicon-photonics platforms. This thesis encompasses systematic and consistent efforts with the goal to achieve the key building blocks for a comprehensive integrated nanophotonic platform in LN. It involves work on the technology side, sustained and complemented by modelling and experiments, ultimately leading to the demonstration of a few novel devices. Ultrahigh field confinement in nanophotonic waveguides is accompanied by the appearance of non-negligible longitudinal components in the guided optical fields. By fabricating high-quality LN nanopillars and analyzing with theory and experiments their second harmonic generation (SHG) response, we provide evidence for the existence of longitudinal field components and demonstrate the possibility to reshape the SHG polar emission properties of these submicrometric waveguides by fine-tuning the nanopillar size. This thesis also presents a different technological approach, allowing the fabrication of photonic wires as small as 250 nm with lengths up to 1 cm on LN-on-insulator (LNOI), suitable for upscaling to photonic integrated circuit (PIC) architectures. By optimizing the fabrication process, the propagation losses of single-mode waveguides at telecom wavelengths on this platform were brought down from 76 to 1.13 dB/cm. Fine-pitch waveguide structuring was also successfully achieved, enabling LNOI-to-fiber grating couplers and waveguide Bragg gratings, the latter featuring record extinction ratios in LNOI (45 dB), comparable to the state of the art in silicon. The thesis involves also theoretical work on the design of photonic wires where the interplay between LN and waveguide birefringence is used to achieve polarization-insensitive operation for the fundamental guided modes. Finally, two demonstrators are provided for novel and emerging applications of LN to the life sciences, using LNOI surface-patterned templates for enhanced Raman spectroscopy and LN templates for controlled neuron growth and manipulation in microfluidic environments, respectively.QC 20181004</p

Integrated Nanophotonic Devices in Lithium Niobate

Lithium niobate (LN) is a ferroelectric crystal offering a broad transparency spectrum, together with excellent electro-optic and nonlinear optical properties. Thanks to them, LN is setting the standard for quantum optics and telecommunications in critical applications such as ultrafast modulation and frequency conversion. The development of a reliable nanophotonic platform in LN can be expected to effectively leverage all such appealing functionalities in compact and integrated formats and provide important and complementary functionalities to current silicon-photonics platforms. This thesis encompasses systematic and consistent efforts with the goal to achieve the key building blocks for a comprehensive integrated nanophotonic platform in LN. It involves work on the technology side, sustained and complemented by modelling and experiments, ultimately leading to the demonstration of a few novel devices. Ultrahigh field confinement in nanophotonic waveguides is accompanied by the appearance of non-negligible longitudinal components in the guided optical fields. By fabricating high-quality LN nanopillars and analyzing with theory and experiments their second harmonic generation (SHG) response, we provide evidence for the existence of longitudinal field components and demonstrate the possibility to reshape the SHG polar emission properties of these submicrometric waveguides by fine-tuning the nanopillar size. This thesis also presents a different technological approach, allowing the fabrication of photonic wires as small as 250 nm with lengths up to 1 cm on LN-on-insulator (LNOI), suitable for upscaling to photonic integrated circuit (PIC) architectures. By optimizing the fabrication process, the propagation losses of single-mode waveguides at telecom wavelengths on this platform were brought down from 76 to 1.13 dB/cm. Fine-pitch waveguide structuring was also successfully achieved, enabling LNOI-to-fiber grating couplers and waveguide Bragg gratings, the latter featuring record extinction ratios in LNOI (45 dB), comparable to the state of the art in silicon. The thesis involves also theoretical work on the design of photonic wires where the interplay between LN and waveguide birefringence is used to achieve polarization-insensitive operation for the fundamental guided modes. Finally, two demonstrators are provided for novel and emerging applications of LN to the life sciences, using LNOI surface-patterned templates for enhanced Raman spectroscopy and LN templates for controlled neuron growth and manipulation in microfluidic environments, respectively.QC 20181004</p

Integrated Nanophotonic Devices in Lithium Niobate

Lithium niobate (LN) is a ferroelectric crystal offering a broad transparency spectrum, together with excellent electro-optic and nonlinear optical properties. Thanks to them, LN is setting the standard for quantum optics and telecommunications in critical applications such as ultrafast modulation and frequency conversion. The development of a reliable nanophotonic platform in LN can be expected to effectively leverage all such appealing functionalities in compact and integrated formats and provide important and complementary functionalities to current silicon-photonics platforms. This thesis encompasses systematic and consistent efforts with the goal to achieve the key building blocks for a comprehensive integrated nanophotonic platform in LN. It involves work on the technology side, sustained and complemented by modelling and experiments, ultimately leading to the demonstration of a few novel devices. Ultrahigh field confinement in nanophotonic waveguides is accompanied by the appearance of non-negligible longitudinal components in the guided optical fields. By fabricating high-quality LN nanopillars and analyzing with theory and experiments their second harmonic generation (SHG) response, we provide evidence for the existence of longitudinal field components and demonstrate the possibility to reshape the SHG polar emission properties of these submicrometric waveguides by fine-tuning the nanopillar size. This thesis also presents a different technological approach, allowing the fabrication of photonic wires as small as 250 nm with lengths up to 1 cm on LN-on-insulator (LNOI), suitable for upscaling to photonic integrated circuit (PIC) architectures. By optimizing the fabrication process, the propagation losses of single-mode waveguides at telecom wavelengths on this platform were brought down from 76 to 1.13 dB/cm. Fine-pitch waveguide structuring was also successfully achieved, enabling LNOI-to-fiber grating couplers and waveguide Bragg gratings, the latter featuring record extinction ratios in LNOI (45 dB), comparable to the state of the art in silicon. The thesis involves also theoretical work on the design of photonic wires where the interplay between LN and waveguide birefringence is used to achieve polarization-insensitive operation for the fundamental guided modes. Finally, two demonstrators are provided for novel and emerging applications of LN to the life sciences, using LNOI surface-patterned templates for enhanced Raman spectroscopy and LN templates for controlled neuron growth and manipulation in microfluidic environments, respectively.QC 20181004</p

Impact of longitudinal fields on second harmonic generation in lithium niobate nanopillars

An optimized focused ion beam process is used to fabricate micrometer-long LiNbO3 nanopillars with diameters varying between 150 and 325 nm. Polarimetric mappings of second harmonic generation from a wavelength of 850 nm demonstrate the ability to modify the polarization features of the nonlinear response through a fine adjustment of the pillar size. The effect is ascribed to the non-negligible contribution of the longitudinal fields associated with sub-wavelength light confinement in the LiNbO3 nanopillars. The results also highlight the importance of a fine control over the nanopillar size in order to effectively engineer their nonlinear response

Anti-lung Cancer Marine Compounds: A Review

Lung cancer is one of the most common and lethal cancers in human beings. Lung cancer has been divided into two major types: small cell lung cancer (SCLC) and non-small cell lung carcinoma (NSCLC). Current drugs suffer from various side effects, and the insufficient efficacy of present treatments creates a desire for better more efficient new drugs. This review compares the diversity of marine-derived bioactive compounds from different marine species. Some of the natural products from marine resources are in different stages of clinical trials. By the way, most of them have been studied in vitro and in vivo. Additionally, in this review, the mechanisms of action of marine-derived anti-lung cancer components on lung cancer cell lines have been reviewed. In addition, considering growing rate and the high costs of cancer research, attention must be paid to some aspects of targeting and developing anti-lung cancer drug. In better words, like the other therapeutic strategies that have their particular challenges and weak points, several challenges about marine-derived anti-lung cancer components which exist for scientists for doing research are explained. Moreover, as the attentions in the field of cancer therapy are focused on designing and developing new anticancer strategies for the treatment of cancer in the future, the application of marine-derived anti-lung cancer components in the field of future cancer therapy and their role in future anticancer strategies are briefly discussed

Photoinduced Enhanced Raman from Lithium Niobate on Insulator Template

© 2018 American Chemical Society. Photoinduced enhanced Raman spectroscopy from a lithium niobate on insulator (LNOI)-silver nanoparticle template is demonstrated both by irradiating the template with 254 nm ultraviolet (UV) light before adding an analyte and before placing the substrate in the Raman system (substrate irradiation) and by irradiating the sample in the Raman system after adding the molecule (sample irradiation). The photoinduced enhancement enables up to an ∼sevenfold increase of the surface-enhanced Raman scattering signal strength of an analyte following substrate irradiation, whereas an ∼threefold enhancement above the surface-enhanced signal is obtained for sample irradiation. The photoinduced enhancement relaxes over the course of ∼10 h for a substrate irradiation duration of 150 min before returning to initial signal levels. The increase in Raman scattering intensity following UV irradiation is attributed to photoinduced charge transfer from the LNOI template to the analyte. New Raman bands are observed following UV irradiation, the appearance of which is suggestive of a photocatalytic reaction and highlight the potential of LNOI as a photoactive surface-enhanced Raman spectroscopy substrate.Science Foundation Irelan