The role of virtual photons in nanoscale photonics

The fundamental theory of processes and properties associated with nanoscale photonics should properly account for the quantum nature of both the matter and the radiation field. A familiar example is the Casimir force, whose significant role in nanoelectromechanical systems is widely recognised; the correct representation invokes the creation of short-lived virtual photons from the vacuum. In fact, there is an extensive range of nanophotonic interactions in which virtual photon exchange plays a vital role, mediating the coupling between particles. This review surveys recent theory and applications, also exhibiting novel insights into key electrodynamic mechanisms. Examples are numerous and include: laser-induced inter-particle forces known as optical binding; non-parametric frequency-conversion processes especially in rare-earth doped materials; light-harvesting polymer materials that involve electronic energy transfer between their constituent chromophores. An assessment of these and the latest prospective applications concludes with a view on future directions of research

Stable optical trapping and sensitive characterization of nanostructures using standing- wave Raman tweezers

Optical manipulation and label-free characterization of nanoscale structures open up new possibilities for assembly and control of nanodevices and biomolecules. Optical tweezers integrated with Raman spectroscopy allows analyzing a single trapped particle, but is generally less effective for individual nanoparticles. The main challenge is the weak gradient force on nanoparticles that is insufficient to overcome the destabilizing effect of scattering force and Brownian motion. Here, we present standing-wave Raman tweezers for stable trapping and sensitive characterization of single isolated nanostructures with a low laser power by combining a standing-wave optical trap with confocal Raman spectroscopy. This scheme has stronger intensity gradients and balanced scattering forces, and thus can be used to analyze many nanoparticles that cannot be measured with single-beam Raman tweezers, including individual single-walled carbon nanotubes (SWCNT), graphene flakes, biological particles, SERS-active metal nanoparticles, and high-refractive semiconductor nanoparticles. This would enable sorting and characterization of specific SWCNTs and other nanoparticles based on their increased Raman fingerprints

Ultra-precise manipulation and assembly of nanoparticles using three fundamental optical forces

The invention of the laser in 1960 opened the door for a myriad of studies on the interactions between light and matter. Eventually it was shown that highly focused laser beams could be used to con fine and manipulate matter in a controlled way, and these instruments were known as optical traps. However, challenges remain as there is a delicate balance between object size, precision of control, laser power, and temperature that must be satisfied. In Part I of this dissertation, I describe the development of two optical trapping instruments which substantially extend the allowed parameter ranges. Both instruments utilize a standing wave optical field to generate strong optical gradient forces while minimizing the optical scattering forces, thus dramatically improving trapping efficiency. One instrument uses a cylinder lens to extend the trapping region into a line focus, rather than a point focus, thereby confining objects to 1D motion. By translation of the cylinder lens, lateral scattering forces can be generated to transport objects along the 1D trapping volume, and these scattering forces can be controlled independently of the optical gradient forces. The second instrument uses a collimated beam to generate wide, planar trapping regions which can con fine nanoparticles to 2D motion. In Part II, I use these instruments to provide the first quantitative measurements of the optical binding interaction between nanoparticles. I show that the optical binding force can be over 20 times stronger than the optical gradient force generated in typical optical traps, and I map out the 2D optical binding energy landscape between a pair of gold nanoparticles. I show how this ultra-strong optical binding leads to the self-assembly of multiple nanoparticles into larger contactless clusters of well de ned geometry. I nally show that these clusters have a geometry dependent coupling to the external optical field.Physic

Strategy of planning and implementation of a mass diplomacy system for the hellenic politeia (republic)

This dissertation is the first research effort on the design of a Strategy of Planning and Implementation of a Mass Diplomacy System for the Hellenic Politeia (Republic).Applied informatics and the capabilities it offers through the mixture of its technologies have allowed greater access to external and internal audiences who are called upon to accept or reject a particular message.The main research objectives of the dissertation are to examine how the new technologies and the political and economic practices that result from them, affect the protection of the national interests of the Hellenic Republic; and how electronic foreign policy, with its various acquired attributes, may create a system of mass diplomacy for the Hellenic Republic.The research also examines the importance of non-governmental players, whether they are organizations, businesses or financial formations, loose political coalitions, pressure groups with a common theme, and the indirect or direct influence they have on a country's governance, due to the technological tools they use.It also examines the influence of technological-information tools, which is often disproportionate to their size and can be utilised by the state institutions or act against them as per case.We are also developing new cases of research, conforming to the above, used to create and control possible behavioral patterns of Hellenic citizens.According to the research, and after examining various case studies and conducting statistical research through a structural equations model about the Greek crisis, mass diplomacy is now a precious and important tool for a political player to develop his foreign policy and to promote his message and his positions;while at the same time dampening the influence of foreign, external actors in his own internal audience.Through the hypotheses examined, concurrently with the statistical study of how the Hellenic citizen behaves towards the external and internal messages he receives and how they influence his decisions, basic conclusions were reached that can contribute to the creation of a strategy for the confrontation of a full spectrum information warfare against the republic.The main conclusions of the dissertation are that national interests mutate and require the use of tools of a different texture, of "soft" power, to protect the "hard" national interests necessary for the operation and sovereignty of the Hellenic Republic.The capability of direct access to external audiences for the promotion of national positions and interests as well as the possibility of direct and interactive contact between the Hellenic Republic and the Ηellenes is necessary; at the same time contributing to the creation of an integrated system of mass diplomacy in a context where a non-governmental political actor becomes more important because of the ability to set the operational stage. Information cannot exist in isolation. It has consequences, and it predisposes a framework of behavior and action. The creation of "influence models" of the Hellenic population that describe the relationship between the transmitted message and the final behavior of individuals, is a necessary action for national defense and the protection of the population and of any concept of democracy.Η παρούσα διατριβή αποτελεί την πρώτη ερευνητική προσπάθεια σχετικά με την κατάστρωση στρατηγικής σχεδιασμού και εφαρμογής συστήματος Μαζικής Διπλωματίας για την Ελληνική Πολιτεία.Η εφαρμοσμένη πληροφορική και οι δυνατότητες που προσφέρει μέσω του μείγματος των τεχνολογιών που διαθέτει, έχουν επιτρέψει την μεγαλύτερη πρόσβαση σε εξωτερικά και εσωτερικά ακροατήρια που καλούνται να αποδεχθούν ή να απορρίψουν ένα συγκεκριμένο μήνυμα.Οι κύριοι ερευνητικοί στόχοι της διατριβής είναι να εξετάσει με ποιον τρόπο οι νέες τεχνολογίες και οι πολιτικές και οικονομικές πρακτικές που άγονται από αυτές επηρεάζουν την προστασία των εθνικών συμφερόντων του Ελληνικού κράτους και πώς η ηλεκτρονική εξωτερική πολιτική με τα διάφορα επίκτητα χαρακτηριστικά που της αποδίδονται μπορεί να συντελέσει στην δημιουργία συστήματος μαζικής διπλωματίας για την Ελληνική πολιτεία.Επίσης εξετάζεται η σημασία των μη-κυβερνητικών παικτών, είτε αυτοί είναι οργανώσεις, επιχειρηματικοί ή οικονομικοί σχηματισμοί, χαλαροί πολιτικοί συνδυασμοί, ομάδες πίεσης με κοινή θεματολογία, στον έμμεσο η άμεσο επηρεασμό της διακυβέρνησης μιας χώρας, λόγω των τεχνολογικών εργαλείων που χρησιμοποιούν. Ακόμη, εξετάζεται η επιρροή των τεχνολογικών-πληροφοριακών εργαλείων, που είναι πολλές φορές δυσανάλογη του μεγέθους τους και μπορεί να χρησιμοποιηθεί από τα πολιτειακά όργανα ή να δράσει εναντίον τους κατά το δοκούν.Στην παρούσα έρευνα αναπτύσσονται επίσης νέες υποθέσεις έρευνες , σύμμορφες προς τις προαναφερόμενες, που χρησιμοποιούνται για την δημιουργία και έλεγχο πιθανών μοντέλων συμπεριφοράς των Ελλήνων πολιτών.Σύμφωνα με την έρευνα και αφότου εξετάσθηκαν διάφορες μελέτες περιπτώσεων και έγινε στατιστική έρευνα μέσω υποδείγματος δομικών εξισώσεων σχετικά με την Ελληνική κρίση, η μαζική διπλωματία πλέον αποτελεί πολύτιμο και σημαντικό εργαλείο στο να καταστρώσει ένας πολιτικός παίκτης την εξωτερική του πολιτική και να προάγει το μήνυμα του και τις θέσεις του, ενώ παράλληλα αμβλύνει την επιρροή ξένων,εξωτερικών παραγόντων στο δικό του εσωτερικό ακροατήριο.Η διατριβή μέσω των υποθέσεων που εξετάστηκαν, αλλά και με την στατιστική μελέτη του πώς συμπεριφέρεται ο Έλληνας πολίτης στα εξωτερικά και εσωτερικά μηνύματα και πώς αυτά επηρεάζουν τις αποφάσεις του, κατέληξε σε βασικά συμπεράσματα που μπορούν να συμβάλλουν στην δημιουργία στρατηγικής για την αντιμετώπιση του πληροφοριακού πολέμου πλήρους φάσματος που εξασκείται κατά της χώρας.Βασικά συμπεράσματα της διατριβής είναι ότι τα εθνικά συμφέροντα μεταλλάσσονται και απαιτούν και την χρήση εργαλείων διαφορετικής υφής, "μαλακής" ισχύος, ώστε να προστατευθούν τα "σκληρά" εθνικά συμφέροντα, τα απαραίτητα στην λειτουργία και κυριαρχία της Ελληνικής Πολιτείας. Επίσης, η δυνατότητα άμεσης πρόσβασης σε εξωτερικά ακροατήρια για την προώθηση εθνικών θέσεων και συμφερόντων καθώς και η δυνατότητα άμεσης και διαδραστικής επαφή μεταξύ της Ελληνικής Πολιτείας και των Ελλήνων, είναι αναγκαία και συνάμα συντελεί στην δημιουργία ολοκληρωμένου συστήματος μαζικής διπλωματίας σε ένα πλαίσιο όπου ο μη-κυβερνητικός πολιτικός ηθοποιός αποκτά μεγαλύτερη σημασία λόγω της δυνατότητας που έχει να ορίσει την σκηνή του. Η πληροφορία δεν μπορεί να υπάρξει σε απομόνωση. Έχει συνέπειες, και προδιαθέτει πλαίσιο συμπεριφοράς και ενεργειών. Η δημιουργία "μοντέλων επηρεασμού" του ελληνικού πληθυσμού που περιγράφουν την σχέση μεταξύ του μεταδιδόμενου μηνύματος και της τελικής συμπεριφοράς των ατόμων είναι απαραίτητη ενέργεια για την εθνική άμυνα και την προστασία του πληθυσμού και της όποιας έννοιας δημοκρατίας

Ultrastrong Optical Binding of Metallic Nanoparticles

We demonstrate nanometer precision manipulation of multiple nanoparticles at room temperature. This is achieved using the optical binding force, which has been assumed to be weak compared to the optical gradient and scattering forces. We show that trapping by the optical binding force can be over 20 times stronger than by the gradient force and leads to ultrastable, rigid configurations of multiple nanoparticles free in solution – a realization of “optical matter.” In addition, we demonstrate a novel trapping scheme where even smaller nanoparticles are trapped between larger “anchor” particles. Optical binding opens the door for the observation of collective phenomena of nanoparticles and the design of new materials and devices made from optical matter

Media 1: High precision and continuous optical transport using a standing wave optical line trap

Originally published in Optics Express on 10 October 2011 (oe-19-21-20833

Ultrastrong Optical Binding of Metallic Nanoparticles

We demonstrate nanometer precision manipulation of multiple nanoparticles at room temperature. This is achieved using the optical binding force, which has been assumed to be weak compared to the optical gradient and scattering forces. We show that trapping by the optical binding force can be over 20 times stronger than by the gradient force and leads to ultrastable, rigid configurations of multiple nanoparticles free in solution – a realization of “optical matter.” In addition, we demonstrate a novel trapping scheme where even smaller nanoparticles are trapped between larger “anchor” particles. Optical binding opens the door for the observation of collective phenomena of nanoparticles and the design of new materials and devices made from optical matter