The Materials Challenge in Diffraction‐Unlimited Direct‐Laser‐Writing Optical Lithography

Abstract

Using a novel photoresist (composed of pentaerythritol triacrylate and isopropyl thioxanthone) that favors stimulated emission depletion by a π‐π* transition and using a two‐color two‐photon excitation scheme, 65‐nm wide lines are achieved. This value is limited by parasitic two‐photon absorption of the continuous‐wave depletion beam. It is estimated that, without this process, line widths of 30 nm are in reach.

Materials and technologies for fabrication of three-dimensional microstructures with sub-100 nm feature sizes by two-photon polymerization

“…[1][2][3][4] Developments of new materials and illumination concepts like the STED lithography [5][6][7] have pushed the lateral dimensions of realizable structures below 100 nm. With the variability of the technology, several applications have emerged, e.g., in the field of micro-optics, where the fabrication of photonic crystals 8,9 or micro-optical elements [10][11][12][13] has been demonstrated.…”

The interplay of different relaxation channels in the excited state dynamics of photoinitiators

“…Therefore only weak fluorescence would be expected. Surprisingly, ITX exhibits a fluorescence quantum yield of 15 % [10]. Thus, any other channel competing for S 1 population has to be rather inefficient.…”

Optically Clear and Resilient Free-Form <em>&micro;</em>-Optics 3D-Printed via Ultrafast Laser Lithography

“…In 3DLL a well chosen photoinitiator (PI) can improve fabrication throughput and structure qualities for a material used [6,7,[19][20][21]. The set of fabrication parameters needed for structuring material is generally refereed as fabrication window.…”