We introduce an electron beam excitation assisted optical microscope, and demonstrate its higher than 50 nm resolution. In the microscope, a light source having a size of a few nanometers is excited by a focused electron beam in a luminescent film. The microscope makes it possible to observe the dynamic behavior of living biological specimens in various surroundings, such as air or liquids. The microscope enables the observation of optical constants such as the absorption, refractive index, polarization, and their dynamic behavior on a nanometric scale. We also introduce a technique in which an electron-beam directly irradiates the labeled molecules on cells. The microscope opens up new microscopy applications in nano-technology and nano-science.

Layered transition-metal dichalcogenides (TMD), known as 2D semiconductors, have recently been revisited. We show that the electronic properties of a single-layered TMD can indeed be altered by doping or alloying, and their structures have been revealed with atomic precision. We have also demonstrated that the phase transitions among polymorphic phases with different properties can be controllably triggered by an electron beam, and that the fabrication of nano-devices within single-layer MoS₂ indeed becomes possible under the TEM observations.

Skyrmions – a spin-swirling vortex-like object composed of 10²-10⁴ individual spins – can behave like a nanometric particle in a magnet by being protected by its topology. In magnets, e.g., MnSi, with a chiral (handedness) structure, the skyrmion crystal was observed by a neutron scattering experiment in 2009 and the individual skyrmion form was observed by an electron microscope in 2010. Since then, skyrmions have attracted intense attention, and studies are going on regarding the theories of creation mechanisms, the search for materials, and the design of devices. Of these, developments leading towards applications have been recently reported such as the realization of skyrmions at room temperature, the control of the size and helicity of skyrmions, the rectification effect of microwave, etc. In this article, starting from the fundamentals, we describe recent research on skyrmions, mentioning the perspective from the next-generation devices utilizing skyrmions.

Nematic liquid crystals (LCs) with large electrical and optical anisotropies are easily operated with low voltages. The LC molecular orientation is controlled by applying an external electric field and then the optical properties of an LC device are changed. These materials have been widely used in flat display devices. Other LC applications without any mechanical movements have become increasingly of interest in recent years.

In this paper, I introduce LC optical devices such as an LC lens and LC micro - lens array for tuning a focal length and beam-steering properties in the visible and infrared region. A three-dimensional imaging system, for determining the all - focused images and depth mapping properties through the use of a low - voltage - driving LC lens, is also described.

Computer holography deals with the phenomena of holography in a computer, including digital holography and computer-generated holograms. The application of computer holography is very wide. In this article, we introduce a holographic scanner which can record large holograms and a holographic projector.

Carbon nanotube (CNT) thin films are rare materials with multi-functionality in addition to superior electric, optical and mechanical characteristics. This article introduces all-carbon devices having a semiconductor layer and electrodes, with wiring made of a CNT thin film. They are flexible and transparent as well as having the ability to be thermoformed into a variety of 3D shapes. Taking advantage of these characteristics allows the realization of unobservable devices or 3D or highly designable devices.

We studied microwave kinetic inductance detectors (MKIDs) using niobium nitride (NbN) thin films for applying two-dimensional array detectors for Fourier transform infrared spectroscopy (FT-IR) operating at 4K. We proposed a dual-function spiral strip (DFSS) for an MKID array, which simultaneously acts as a small microwave resonator with a high Q_u and a wide–band THz antenna. 25 array MKIDs were fabricated using 20-nm-thick NbN films deposited on an r-plane sapphire substrate. We clearly observed half-wavelength resonances around 2.0 GHz at 2.245 K for 25 devices. The optical responses were also confirmed using hot and cold radiation. We believe that the DFSS-MKIDs are a promising detector for applications of the FT-IR.

The Railway Research Institute has been developing a superconducting flywheel energy storage system for regenerative energy. Its flywheel is supported by a superconducting magnetic bearing using a superconducting coil as a stator and bulk superconductors as a rotor. I have designed and manufactured an experimental apparatus based on this structure and have demonstrated the feasibility of the structure.

Spectroscopy is one of the most prevalent characterization techniques for the materials sciences, since it is performed in a contact-free and non-destructive manner. Tips for absorption spectroscopy using conventional double-beam spectrophotometer are introduced first, as well as tips for photoluminescence spectroscopy using ad-hoc setups employing optical components.