Deterministic all-optical magnetization writing facilitated by non-local transfer of spin angular momentum

Ever since the discovery of all-optical magnetization switching (AOS) around a decade ago, this phenomenon of manipulating magnetization using only femtosecond laser pulses has promised a large potential for future data storage and logic devices. Two distinct mechanisms have been observed, where the final magnetization state is either defined by the helicity of many incoming laser pulses, or toggled by a single pulse. What has thus far been elusive, yet essential for applications, is the deterministic writing of a specific magnetization state with a single laser pulse. In this work we experimentally demonstrate such a mechanism by making use of a spin polarized current which is optically generated in a ferromagnetic reference layer, assisting or hindering switching in an adjacent Co/Gd bilayer. We show deterministic writing of an 'up' and 'down' state using a sequence of 1 or 2 pulses, respectively. Moreover, we demonstrate the non-local origin of the effect by varying the magnitude of the generated spin current. Our demonstration of deterministic magnetization writing could provide an essential step towards the implementation of future optically addressable spintronic memory devices

Novel optical metrology for inspection of nanostructures fabricated by substrate conformal imprint lithography

Substrate conformal imprint lithography (SCIL) technology enables the fabrication of complex and non-trivial 3D nanostructures such a slanted gratings and metasurfaces with sub-10 nm resolution over large areas for industrial-scale production, which can be fabricated in a single lithography step. This technology utilizes novel composite silicone rubber stamps that provide versatility in addition to high precision. To inspect the quality and reproducibility of the nanostructures that are fabricated using SCIL, a novel optical characterization method using Fourier microscopy is proposed. In this method, nanostructures are illuminated under a microscope objective using a collimated light beam at different incident angles and the properties of the reflected and/or diffracted beams are analysed to extract the critical dimensions of the nanostructures. This fast and non-destructive method has the potential for being used as an in-line inspection technology to extract the critical dimensions of the nanostructures over large areas and improve the overall properties of nanostructured surfaces.</p

Distributed lighting control with daylight and occupancy adaptation

A distributed lighting system of multiple intelligent luminaires is considered for providing daylight and occupancy adaptive illumination. Each intelligent luminaire has a light sensor and an occupancy sensor that provides information on local light level and presence respectively, a controller that adapts dimming level of the light source and a communication module. The illumination objective is to provide a desired average illuminance value over occupied/unoccupied zones at the workspace, specified in turn by occupancy-based set-points at corresponding light sensors. Two classes of proportional-integral (PI) controllers are considered to adapt the dimming levels of the luminaires to varying daylight levels under two networking scenarios. In one scenario, each controller operates stand-alone, sharing no information across other controllers, and has information about global occupancy. In the second scenario, controllers exchange control information within a neighborhood. The performance of the considered controllers is evaluated using photometric data from a DIALux implementation of an example open-office under different daylight and occupancy scenarios. A distributed lighting system of multiple intelligent luminaires is considered for providing daylight and occupancy adaptive illumination. Each intelligent luminaire has a light sensor and an occupancy sensor that provides information on local light level and presence respectively, a controller that adapts dimming level of the light source and a communication module. The illumination objective is to provide a desired average illuminance value over occupied/unoccupied zones at the workspace, specified in turn by occupancy-based set-points at corresponding light sensors. Two classes of proportional-integral (PI) controllers are considered to adapt the dimming levels of the luminaires to varying daylight levels under two networking scenarios. In one scenario, each controller operates stand-alone, sharing no information across other controllers, and has information about global occupancy. In the second scenario, controllers exchange control information within a neighborhood. The performance of the considered controllers is evaluated using photometric data from a DIALux implementation of an example open-office under different daylight and occupancy scenarios

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In dit boek staat de volgende vraag centraal: op welke wijze kunnen pedagogen, onderwijskundigen en psychologen bijdragen aan de realisering van de WSNS-doelstellinge

Distributed lighting control with daylight and occupancy adaptation

A distributed lighting system of multiple intelligent luminaires is considered for providing daylight and occupancy adaptive illumination. Each intelligent luminaire has a light sensor and an occupancy sensor that provides information on local light level and presence, respectively, and has a controller that adapts dimming level of the light source and a communication module. The illumination objective is to provide a desired average illuminance value over occupied/unoccupied zones at the workspace, specified in turn by occupancy-based set-points at corresponding light sensors. Two classes of proportional-integral (PI) controllers are considered to adapt the dimming levels of the luminaires to varying daylight levels under two networking scenarios. In one scenario, each controller operates stand-alone, sharing no information across other controllers, and has information about global occupancy. In the second scenario, controllers exchange control information within a neighborhood. The performance of the considered controllers is evaluated using photometric data from a DIALux implementation of an example open-plan office under different daylight and occupancy scenarios

Deterministic all-optical magnetization writing facilitated by non-local transfer of spin angular momentum

Ever since the discovery of all-optical magnetization switching (AOS) around a decade ago, this phenomenon of manipulating magnetization using only femtosecond laser pulses has promised a large potential for future data storage and logic devices. Two distinct mechanisms have been observed, where the final magnetization state is either defined by the helicity of many incoming laser pulses, or toggled by a single pulse. What has thus far been elusive, yet essential for applications, is the deterministic writing of a specific magnetization state with a single laser pulse. In this work we experimentally demonstrate such a mechanism by making use of a spin polarized current which is optically generated in a ferromagnetic reference layer, assisting or hindering switching in an adjacent Co/Gd bilayer. We show deterministic writing of an 'up' and 'down' state using a sequence of 1 or 2 pulses, respectively. Moreover, we demonstrate the non-local origin of the effect by varying the magnitude of the generated spin current. Our demonstration of deterministic magnetization writing could provide an essential step towards the implementation of future optically addressable spintronic memory devices

Deterministic all-optical magnetization writing facilitated by non-local transfer of spin angular momentum

Ever since the discovery of all-optical magnetization switching (AOS) around a decade ago, this phenomenon of manipulating magnetization using only femtosecond laser pulses has promised a large potential for future data storage and logic devices. Two distinct mechanisms have been observed, where the final magnetization state is either defined by the helicity of many incoming laser pulses, or toggled by a single pulse. What has thus far been elusive, yet essential for applications, is the deterministic writing of a specific magnetization state with a single laser pulse. In this work we experimentally demonstrate such a mechanism by making use of a spin polarized current which is optically generated in a ferromagnetic reference layer, assisting or hindering switching in an adjacent Co/Gd bilayer. We show deterministic writing of an 'up' and 'down' state using a sequence of 1 or 2 pulses, respectively. Moreover, we demonstrate the non-local origin of the effect by varying the magnitude of the generated spin current. Our demonstration of deterministic magnetization writing could provide an essential step towards the implementation of future optically addressable spintronic memory devices. Ever since the discovery of all-optical magnetization switching (AOS) around a decade ago, this phenomenon of manipulating magnetization using only femtosecond laser pulses has promised a large potential for future data storage and logic devices. Two distinct mechanisms have been observed, where the final magnetization state is either defined by the helicity of many incoming laser pulses, or toggled by a single pulse. What has thus far been elusive, yet essential for applications, is the deterministic writing of a specific magnetization state with a single laser pulse. In this work we experimentally demonstrate such a mechanism by making use of a spin polarized current which is optically generated in a ferromagnetic reference layer, assisting or hindering switching in an adjacent Co/Gd bilayer. We show deterministic writing of an 'up' and 'down' state using a sequence of 1 or 2 pulses, respectively. Moreover, we demonstrate the non-local origin of the effect by varying the magnitude of the generated spin current. Our demonstration of deterministic magnetization writing could provide an essential step towards the implementation of future optically addressable spintronic memory devices