BEGIN:VCALENDAR VERSION:2.0 PRODID:Icfo X-PUBLISHED-TTL:P1W BEGIN:VEVENT UID:69d257181cf13 DTSTART:20230428T120000Z SEQUENCE:0 TRANSP:OPAQUE LOCATION:Online (Teams) SUMMARY:ICFO | ADEEL AFRIDI CLASS:PUBLIC DESCRIPTION:Optical metasurfaces established themselves as potential platfo rm for planar and integrated optics. Progress in the material sciences and fabrication process paves the way towards ultra-thin metasurface based de vices\, also known as meta-devices. Meta-devices include holograms\, flat lenses\, wave-plates\, polarizers and deflectors. Amongst these meta-devic es\, great effort focuses toward the development of high performance\, abe rrations-free\, and multi-functional metalenses.\nHigh refractive index an d lossless dielectric materials have enabled metalenses with near-unity tr ansmission and high numerical aperture. However\, the static nature of met alenses limits their use for the applications where continuous and on dema nd tunability of lens operation is required such as imaging and adaptive v ision.\nIn this thesis\, I developed two different techniques to achieve r econfigurability in metasurfaces which I used to create reconfigurable met alens devices. devices based on two types of reconfigurability techniques. First technique achieves focal\nlength tunability of a dielectric metalen s by utilizing the electro-thermo-optical effect to change the refractive index of the surrounding media. The electro-thermo-optically controlled me talens exhibits linear and continuous focal length tunability\, high effic iency and low power consumption with switching time of the order of 100 ms . The second varifocal metalens Device takes advantage of the optomechania l effect to introduce change in the geometry of the metalens itself. Carve d onto a freestanding ultra-thin silicon membrane\, the metalens exhibits continuous and linear focal length tunability with fast response time as s hort as a few &mu\;s.\n \;\nThesis Director: Prof Dr. Romain Quidant DTSTAMP:20260405T123536Z END:VEVENT END:VCALENDAR