1,355,539 research outputs found
Adaptive graphene electronics and plasmonics
No full textGraphene, the world’s first two dimensional material, has attracted great interest in the scientific community due to its unique behaviours such as the dramatic tunability of its electronic and optical properties, strong lightmatter interactions, and high values of carrier mobility which render graphene as a fascinating material for photodetection, plasmonic devices, and modulation of terahertz frequency radiation. To realise the next generation of graphene devices we must find new ways to adaptively control the electronic and optical properties of graphene and other two dimensional materials. In this thesis I propose a method to optically control the electronic properties of graphene in a spatially resolved, non-volatile, yet reversible manner via the use of photorefractive lithium niobate. The method I propose relies on the ability of lithium niobate to sustain optically defined charge distributions which result in large electrostatic fields at the surface of the crystal. By transferring graphene onto lithium niobate crystals I show that the optically defined electrostatic surface charges in the substrate are capable of tuning the DC electrical conductivity of graphene in a behaviour which is non-volatile yet reversible under thermal annealing. Further, I utilise this effect in a plasmonic device consisting of a hybrid graphene-metal metasurface on lithium niobate where the optical tuning effect is capable of altering the transmissive properties of the device at terahertz frequencies. Finally, I show through simulations that by spatially patterning charge distributions it is possible to create optically defined plasmonic devices on graphene on lithium niobate. Such devices would not need permanent lithographic patterning of metasurfaces, yet instead would rely on optically defined regions of high and low conductivity graphene to sustain a plasmonic resonance. If such devices can be experimentally achieved this would allow for rewritable yet non-volatile plasmonic structures in graphene and open the doors to a truly reconfigurable plasmonic platform for two dimensional materials
Quantum Metrology of Noisy Spreading Channels
No full textWe provide the optimal measurement strategy for a class of noisy channels that reduce to the identity channel for a specific value of a parameter (spreading channels). We provide an example that is physically relevant: the estimation of the absolute value of the displacement in the presence of phase randomizing noise. Surprisingly, this noise does not affect the effectiveness of the optimal measurement. We show that, for small displacement, a squeezed vacuum probe field is optimal among strategies with same average energy. A squeezer followed by photodetection is the optimal detection strategy that attains the quantum Fisher information, whereas the customarily used homodyne detection becomes useless in the limit of small displacements, due to the same effect that gives Rayleigh's curse in optical superresolution. There is a quantum advantage: a squeezed or a Fock state with N average photons allow to asymptotically estimate the parameter with a N better precision than classical states with same energy
The Evolving Landscape of Dentistry: Embracing Connection and Growth
No full textThis article features a monthly column from the Macomb Dental Society Executive Director, Dr. Christopher Gorecki
Gorecki\u27s Symphony No. 3, Op. 36, Sorrowful Songs
No full textThe experience of listening to Gorecki’s Symphony no. 3, op. 36 “Sorrowful Songs” is one that is not easily forgotten. It is not only musically captivating, but also historically fascinating. After its premiere in 1977, Gorecki’s piece captivated listeners across the globe as it became a cultural phenomenon in both Europe and America. The music was a stunning success in both the Classical and popular cultures. What is it about the music that is so captivating? How did the trending, popular thoughts compare to Gorecki’s original ideas and compositional motives? What actually inspired this piece? By looking at the composition and premise of each movement, I am going to introduce how the piece was written around the theme of maternal love and separation of mother and child. The Third Symphony was heavily influenced by Gorecki’s personal past, but also by his Catholic beliefs and by Polish history. The separate texts to this three movement piece deal individually with a mother’s lament over her son’s departure, the Virgin Mary’s grief at her Son’s death, and finally the words of an incarcerated prison girl to her mother. Because of the setting from which the third text was drawn, and because of Gorecki’s Polish history and experiences in the post-holocaust world, many people have interpreted this to be a “war piece” which avenges the sufferers of the Holocaust. According to Gorecki, this piece is a lament- it expresses a profound sense of grief which, arguably, cannot accurately be expressed with words. Gorecki used his music to confront, mourn, and express his pain and the pain of many other people. By finding primary sources, such as interviews of Henryk Gorecki, and by looking at the scholarly books and journals by Luke B. Howard, Adrian Thomas, and other scholars of Polish avant-garde music, I hope to properly understand and express the intentions Gorecki wished to convey by writing The Symphony of Sorrowful Songs
Dataset for Thesis: Adaptive Graphene Electronics and Plasmonics
No full textThis data supports Doctoral thesis University of Southampton 2020/21. This data contains experimental and simulated investigations of graphene on photoresponsive lithium niobate substrates for tunable electronic and plasmonic applications. The data here is saved in CSV (comma separated value) format, which can be opened with a wide range of freely available software, such as text editors, or spreadsheet readers.</span
Gorecki Jan — Divorce in Poland A Contribution to the Sociology of Law
No full textH. J. Gorecki Jan — Divorce in Poland A Contribution to the Sociology of Law. In: Population, 27ᵉ année, n°3, 1972. p. 539
J. Gorecki, Divorce in Poland. A Contribution to the Sociology of Law
No full textJ. Gorecki, Divorce in Poland. A Contribution to the Sociology of Law. In: Revue internationale de droit comparé. Vol. 26 N°2, Avril-juin 1974. pp. 406-407
J. Gorecki, Divorce in Poland. A Contribution to the Sociology of Law
No full textJ. Gorecki, Divorce in Poland. A Contribution to the Sociology of Law. In: Revue internationale de droit comparé. Vol. 26 N°2, Avril-juin 1974. pp. 406-407
Gorecki Jan — Divorce in Poland A Contribution to the Sociology of Law
No full textH. J. Gorecki Jan — Divorce in Poland A Contribution to the Sociology of Law. In: Population, 27ᵉ année, n°3, 1972. p. 539
THz-TDS parameter extraction: Empirical correction terms for the analytical transfer function solution
No full textTerahertz time-domain spectroscopy (TDS) is capable of determining both real and imaginary refractive indices of a wide range of material samples; however, converting the TDS data into complex refractive indices typically involves iterative algorithms that are computationally slow, involve complex analysis steps, and can sometimes lead to non-convergence issues. To avoid using iterative algorithms, it is possible to solve the transfer function analytically by assuming the material loss is low; however, this leads to errors in the refractive index values.Here we demonstrate howthe errors created by solving the transfer function analytically are largely predictable, and present a set of empirically derived equations to diminish the error associated with this analytical solution by an impressive two to three orders of magnitude.We propose these empirical correction terms are well suited for use in industrial applications such as process monitoring where analysis speed and accuracy are of the utmost importance.</p
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