You are cordially invited to the M.S. Thesis Defense Presentation<\/p>\n
\u201cFreeform Maskless Silicon Nanolithography via In-chip Laser Nanostructuring\u201d<\/p>\n
Beliz Do\u011fukaya, M.S. Student in Physics<\/p>\n
Abstract: A long-standing goal in laser nanofabrication is to write functional nanostructures directly in technologically important materials without masks, templates, or cleanroom-intensive processing. Silicon is a critical target for this goal, yet its nanoscale structuring remains limited by trade-offs in resolution, geometric freedom, and fabrication flexibility. This thesis develops a subsurface-to-surface strategy for freeform, maskless silicon nanolithography. Building on in-chip laser nanostructuring, it introduces complementary routes for transforming buried laser-written modifications into surface-accessible functional nanostructures.<\/p>\n
The thesis presents a nanofabrication of freeform nanostructures beneath the silicon surface using spatially modulated infrared laser pulses, followed by polishing and chemical etching. This route enables visible-regime diffraction gratings with 25% efficiency at two wavelengths, and Fresnel lenses based on subwavelength refractive-index modulation [Dogukaya, et al., Optics Express 34, 11271 (2026)] [PCT\/TR2025\/006747]. The second nanolithography method is an ongoing project in which in-chip nanostructures directly guide surface pattern formation [PCT\/TR2025\/007458]. This enables freeform silicon thin-coating patterning supported with preliminary grating and microlens applications in reflection mode. Together, these results establish a toolbox for subsurface-to-surface nanolithography for maskless silicon nanofabrication, opening a new design space for integrated optics, meta-optics, and nanophotonics.<\/p>\n
Advisor: Assoc. Prof. Dr. Onur Tokel
\nDate: Tuesday, June 2, 2026
\nTime: 10:30
\nPlace: SA 240 \u2013 Physics Seminar Room<\/p>\n","protected":false},"excerpt":{"rendered":"
You are cordially invited to the M.S. Thesis Defense Presentation \u201cFreeform Maskless Silicon Nanolithography via In-chip Laser Nanostructuring\u201d Beliz Do\u011fukaya, M.S. Student in Physics Abstract: A long-standing goal in laser nanofabrication is to write functional nanostructures directly in technologically important materials without masks, templates, or cleanroom-intensive processing. Silicon is a [\u2026] <\/p>\n