To record optical images like specialized images to selfies for further processing, the relevant amount of light is absorbed by an image sensor. Such a sensor consists of many sensitive elements -pixels - made of silicon with modern semiconductor nanotechnology. Since nanotechnology is continuously miniaturizing and silicon absorbs light weakly, absorption must be greatly increased to convert light much more efficiently into charge that is detected as a digital image. The innovation of AHEAD is to increase absorption by trapping light in pixels with smart photonic bandgap nanostructures. AHEAD is so flexible that different bands of light can be optimized.

Light microscopy has been a key tool for biological and medical research for centuries, but the limited penetration due to light scattering has restricted its in vivo imaging ability to near-surface region. To overcome this constraint endoscopic techniques based on miniature optical probes have been developed. However, even nowadays high-resolution (<500 nm) multifunctional imaging deep into organs or biotissue (below 1 mm) remains an elusive goal. In this VENI program, I will create the next generation of optical endoscopic methods fully applicable for biovisualization: super-resolution fluorescent imaging and high-resolution chemically-selective label-free imaging. I will develop the breakthrough technologies by integrating wavefront shaping of light in unique multimode photonic crystal fiber probes with advanced optical microscopy methods, such as Raman and super-resolution microscopy. Implementation of cutting-edge methods of optical microscopy in a multimode fiber format is very challenging but extremely beneficial. It will allow drastical improvement of the functionality of fiber endoscopes and provide resolution below the diffraction limit at any depth accessible by endoscopy inside living tissue. The results of this work potentially have broad applications in life sciences and medicine, opening a new era of bioimaging in endoscopic format. New endomicroscopy methods will bring optical biopsy to the next level, by providing minimally-invasive microscopic images of tissues at unparalleled resolution and without artificial biomarkers. It will allow visualization of tiny cell features deep inside living organisms or performing longitudinal observation of dynamic phenomena in their natural environments. The new methods can be used for mass production of a new generation of fiber-optic microscopes. Being easy-to-use, affordable and compact, the new system can be deployed at any Lab and Medical center.

In this project materials systems will be designed that deform and move when light reaches them. This will be realized through a combination of piezo and photovoltaic materials. We call these systems piezo-photomotion devices. It will be explored whether these systems can enable driving of nanorobots and membranes for application in medicine and solar energy conversion.

Binary mixtures of hard colloids self-assemble into a 3D icosahedral quasicrystal under certain conditions. This breakthrough, very recently discovered by the Soft Condensed Matter group in Utrecht (by both simulations and experiments), suggests a way forward for the creation of photonic quasicrystals. Due to their non-periodic structure and exotic symmetries, quasicrystals - when created from particles of the right size and refractive index - are very promising candidates for materials that strongly manipulate visible light via band gaps. Such materials are relevant to fundamental studies and for a wide range of applications, from spontaneous emission control, via sensing, to lighting, lasers, photonic circuitry, photo-catalysis and structural colors. Here we propose a compact program of 5 PhD projects from 4 groups at 2 Universities, which collects all the expertise necessary to pursue this breakthrough. Our goal is to achieve, for the first time, the self-assembly of photonic colloidal icosahedral quasicrystals as well as the associated periodic MgCu2 Laves phase crystals. Real-space studies in index-matched crystals of fluorescent core-shell particles together with computer simulations will provide direct insight into the self-assembly process of importance to many fields. The photonic response of the resulting photonic crystals and quasicrystals will be maximized through two routes: by using high-refractive index particles for the self-assembly process, and by inverting the structure using atomic layer deposition. The successful completion of this challenging task will require guidance from numerical simulations focused on finding the ideal conditions for the nucleation of desired structures, as well as numerical predictions for their photonic properties. Since the lack of periodicity poses challenges to photonic calculations, new methods will be developed based on existing successful eigensolvers for finite periodic crystals. The optical properties of these structures will be studied using reflection and transmission, notably using shaped wavefronts to match the disordered states at the band edge of which little is known to date. To study strongly varying local density of states and photonic correlations we collect emission spectra and lifetimes of dye or quantum dots that serve as internal reporters. After completion, we will achieve a broad range of fundamental new insights and make colloidal self-assembly a viable photonics technology platform.

To sustainably realize future high-tech devices for billions of people, it is crucial to improve their optical functionalities and efficiencies. Remarkably, major relevant Dutch high-tech industries — semiconductor nanofabrication, optical technology, lighting — share common optical technology challenges for such devic-es. Our multidisciplinary team of researchers will develop novel optics with reduced aberrations and dimen-sions, in close collaboration with our users Anteryon, ASML, JMO, Luximprint, Nanoscribe, Schott, Signify (>30 B€/yr turnover) to solve these challenges. FOCUS takes a major step by developing freeform gradient-index optics: from design, materials and fabrication, to metrological verification.