Real-world optimization problems pose major challenges to algorithmic research. For instance, (i) many important problems are believed to be intractable (i.e. NP-hard) and (ii) with the growth of data size, modern applications often require a decision making under {\em incomplete and dynamically changing input data}. After several decades of research, central problems in these domains have remained poorly understood (e.g. Is there an asymptotically most efficient binary search trees?) Existing algorithmic techniques either reach their limitation or are inherently tailored to special cases. This project attempts to untangle this gap in the state of the art and seeks new interplay across multiple areas of algorithms, such as approximation algorithms, online algorithms, fixed-parameter tractable (FPT) algorithms, exponential time algorithms, and data structures. We propose new directions from the {\em structural perspectives} that connect the aforementioned algorithmic problems to basic questions in combinatorics. Our approaches fall into one of the three broad schemes: (i) new structural theory, (ii) intermediate problems, and (iii) transfer of techniques. These directions partially build on the PI's successes in resolving more than ten classical problems in this context. Resolving the proposed problems will likely revolutionize our understanding about algorithms and data structures and potentially unify techniques in multiple algorithmic regimes. Any progress is, in fact, already a significant contribution to the algorithms community. We suggest concrete intermediate goals that are of independent interest and have lower risks, so they are suitable for Ph.D students.

The high current density required for population inversion in organic semiconductors has made the realization of an organic laser diode rather challenging. Here, I propose an organic polariton laser diode (OPLD) in which the threshold is achieved through the mechanism of polariton condensation. This conceptually different lasing mechanism does not require population inversion, suggesting that lasing under electrical injection can be, for the first time, demonstrated in organic semiconductors. To date, most commercial laser diodes are based on inorganic semiconductors, which are expensive materials, require complex fabrication and manufacturing processes, and have a limited range of lasing wavelengths. Organic semiconductors, in contrast, are ideal materials for the industrial production of diode lasers and other optoelectronic devices due to their ease of fabrication and processing, low acquisition-cost, and broad spectrum of emission. The realization of the first OPLD within this fellowship will be tremendously important for the European market. In 2014, diode-laser technology comprised 46% of the total revenue ($9.4 billion) in the global laser market. Moreover, emerging automotive lighting (BMW Laserlight) and high-definition laser display (LG LASER display) technologies could enable diode lasers to overtake the global laser market. Therefore, any steps towards the realization of the first organic laser diode (or organic solid state laser) would represent a significant technological and scientific achievement. Furthermore, the proposed device offers a totally new, due to its electrical pumping, platform for fundamental studies of quantum fluids of light.

Since Richard Feynman's famous talk There is Plenty of Room at the Bottom in 1959, the following decades saw the booming of nanotechnology. One of the fields in which nanotechnology can never be ignored is the development of scientific instruments. Scientific instruments based on nanotechnology have revolutionized many research fields. However, using current instruments to study superfluid He is still challenging, especially for the topological defects (TDs) and topological matter (TM) because the scale of the coherence length of the interesting objects in 3He is just tens of nanometers. The N2PCON (Nanostructures and Nanoelectromechanical devices for Precise CONtrol of topological defects/matter in superfluid He) project will offer a nanotechnology solution to precisely control and study TDs and TM. In this action, I will work in the OtaNano (Finnish national infrastructure for nanoscience and nanotechnology) at Aalto University, with the supervision of Dr. Sami Franssila (Department of Chemistry and Materials Science) and Dr. Vladimir Eltsov (Department of Applied Physics). At the same time, I will also work with my secondment institutes, Royal Holloway, University of London, UK and Lancaster University, UK, to boost this action. The action will produce nanoscale instruments (NEMS, nanostructures) that surpass the current state-of-the-art devices, in both performance and dimension, to reach the quantum world of TDs and TM. N2PCON is expected to provide new tools for superfluid research and also add general knowledge to MEMS/NEMS and cosmology. In the long term, it will boost the MEMS/NEMS research and industry in the EU.

Molecular structure determination is vital for biochemistry, life science, and drug industry. A complete determination of the molecular structure requires both the structural skeleton and atoms therein to be identified. Non-contact Atomic Force Microscopy provided a method to image the real-space structural skeleton of planar organic molecule, however, the chemical identities of each atom that comprise the molecule are yet to be determined. In this proposal, I systematically analyze the physical principle for elemental identification in single molecules and propose a practical method to identify each atom using point spectrum with non-contact atomic force microscope.

The continuous growth of global data traffic pushes the data center technology boundaries and their energy consumption. Data centers already use more than 2% of the global electricity and are expected to consume 20% by 2025. The new generation hyperscale data centers offer a more energy-efficient alternative to conventional data centers but are limited by the current technology restrictions. Silicon photonics has been deemed to solve current bottlenecks for building green hyperscale data centers. However, this technology is challenged by the complicated and expensive fabrication methods of the laser sources, which represent 40% cost of the entire silicon transceiver market. Using a simple fabrication method invented in our ERC Advanced project, we have designed a waveguide light source that can be fabricated onto the silicon-integrated platform with a single-step, straightforward, low-cost, low-temperature and scalable process that lowers the fabrication cost ~10 times compared to the state-of-the-art light sources. Such technologic breakthrough will push the implementation of silicon photonics in hyperscale data centers, allowing them to maintain a low energy footprint while meeting the ever-increasing bandwidth requirements of the growing big data societal challenge. Our project aims to further develop the novel technology and demonstrate its effectiveness for data center applications, to create the first-of-its-kind low-cost and scalable fabrication technology for the silicon photonics market, compatible with the current systems used in the industry. Furthermore, we will prepare and validate the business concept with value chain players, strengthen our IPR strategy, and prepare the commercialization to establish a start-up aiming at serving this significantly growing market (40% Compound Annual Growth Rate).