Massively parallel direct writing of nanoapertures using multi-optical probes and super-resolution near-fields.

Laser direct-writing enables micro and nanoscale patterning, and is thus widely used for cutting-edge research and industrial applications. Various nanolithography methods, such as near-field, plasmonic, and scanning-probe lithography, are gaining increasing attention because they enable fabrication of high-resolution nanopatterns that are much smaller than the wavelength of light. However, conventional methods are limited by low throughput and scalability, and tend to use electron beams or focused-ion beams to create nanostructures. In this study, we developed a procedure for massively parallel direct writing of nanoapertures using a multi-optical probe system and super-resolution near-fields. A glass micro-Fresnel zone plate array, which is an ultra-precision far-field optical system, was designed and fabricated as the multi-optical probe system. As a chalcogenide phase-change material (PCM), multiple layers of Sb65Se35 were used to generate the super-resolution near-field effect. A nanoaperture was fabricated through direct laser writing on a large-area (200 × 200 mm2) multi-layered PCM. A photoresist nanopattern was fabricated on an 8-inch wafer via near-field nanolithography using the developed nanoaperture and an i-line commercial exposure system. Unlike other methods, this technique allows high-throughput large-area nanolithography and overcomes the gap-control issue between the probe array and the patterning surface.

Direct replication of a glass micro Fresnel zone plate array by laser irradiation using an infrared transmissive mold.

It is not yet possible to fabricate micrometer-scale, glass optical components with nanometer-scale precision. Glass thermal imprinting enhances production efficiency. However, dimensional changes caused by shrinkage are inevitable because of phase transitions. Replication is very difficult when high-level pitch precision is essential. We used an infrared-transparent silicon mold and a CO2 laser to perform replica-type, thermal surface texturing at the nanoscale level; we analyzed a glass Fresnel zone plate array to this end. The Fresnel zone plate array was 10 × 10 mm2 in area and featured a 20 × 20 array. The individual Fresnel zone plate diameter was 500 µm and had 21 rings of minimum linewidth 2.9 µm and height 737 nm.

Gigapixel confocal imaging using a massively parallel optical probe array with single directional infinite scanning.

Here we demonstrate high-throughput gigapixel confocal imaging using a massively parallel optical probe array with single directional infinite scanning. For implementation of the single directional infinite scan with high lateral resolution, a parallelogram array micro-objective lens module, composed of two wafer-level microlens arrays, is proposed to generate a massively parallel optical probe array for integration into the confocal imaging system, including an objective-side telecentric relay lens with a low-magnification. To test the feasibility of the proposed system with single directional infinite scanning, we designed and constructed a confocal imaging system using a parallelogram array of multi-optical probes with a massively parallel array size of 200 × 140. The constructed system provides a full width-half maximum lateral resolution of 1.55 µm, as measured by the knife-edge detection method, and a field-of-view width of 28.0 mm with a sampling interval of 1 µm/pixel.