Light can transfer both linear and angular momentum to matter. This constitutes the principle of optical tweezers developed by Arthur Ashkin and can be used for three dimensional trapping and manipulation of objects in a large variety of systems. The optical tweezers can be used in combination with three dimensional structures produced using two photon photopolymerisation process (2PP) in order to provide a source of all optically driven mircomachines that in turn are used for dynamic studies of biological and physical processes. They can also be used to construct heat engines.

Laser-induced forward transfer, a nozzle-free direct printing technology, enables the direct print of various donor materials, such as solids, high viscosity liquids with functional nanoparticles at high density, and even biomaterials, on a receiver owing to laser induced evaporation pressure. An optical vortex with a helical wavefront exhibits a donut-shaped spatial profile and an orbital angular momentum, and it has been leading to new fundamental sciences and advanced technologies. In recent years, we and our co-workers have proposed a new direct printing technology based on optical vortex, here referred as optical vortex laser induced forward transfer, in which a single optical vortex pulse twists the irradiated donor to eject and propel a pico-liter scale spinning microdroplet, thereby enabling well-aligned microdots with high spatial resolution on a receiver substrate. Going beyond conventional LIFT technologies, we here demonstrate the direct 2D print of well-aligned metallic microdots with a diameter of 15~45 µm, consisting of close-packed gold nanoparticles at high density, by the optical vortex laser induced forward transfer with the aid of a spin angular momentum associated with circular polarization. The electrical resistance of printed dot was measured to be ~10-7 Ωm, corresponding to 5-6 times higher than that of bulk gold. Optical vortex laser-induced forward transfer will pave the way towards next-generation printed electronics.

In the advanced optical technology for micro/nano imaging and fabrication, fluctuation in the system causes error to deteriorate the accuracy and the resolution. People use extremely low-noise detectors and electronics. Instruments are installed on a vibration-isolated optical table in a dark and clean room. Vacuum and cryogenic technologies are also used for removing fluctuation. In this presentation, I will discuss on a new method in which fluctuation is exploited as the necessary source of imaging and fabrication. This concept was applied to laser-scanning confocal Raman-scattering microscopy, nano-resolution plasmonic Raman imaging and self-growth of fractal plasmonic nano-structures.

We have already reported the use of commercial Azobenzene molecules for the control of biological membranes. In the current work we have synthesized Azobenzene molecules that have both hydrophobic and hydrophilic opposed ends. Our working hypothesis is that the increased affinity of such molecules with amphiphilic molecules of the biological membrane will increase the impact of photo induced isomerization on the ionic exchange processes across the membrane. However, our preliminary results show that these molecules adopt relatively stable Trans and Cis isomers. The thermal isomerization of newly created (by using UV light) Cis molecules into their Trans form is almost inexistant. Thus, the process of isomerization is saturated quickly. This is the reason why we use a second (visible) light source to initiate the back photo isomerization and to maintain the continuous Trans-Cis and Cis-Trans isomerization process. The corresponding spectral investigations in water and mobility media as well as bacterial systems will be reported.

Molecular motion in polymers is frozen below the glass transition temperature T-g and changes of viscoelastic functions are most spectacular near T-g. Exceptional enhancement of molecular mobility and a decrease of polymer viscosity, by several orders of magnitude, down to the viscous flow regime, are observed way below T-g by light absorption. Relaxation processes, which take decades to centuries in some high-T-g polymers, are reduced to minute timescales by sub-T-g light absorption. Here we develop a model for this intriguing albeit spectacular action of light on glass forming materials and we propose experiments to relate light absorption to materials properties. The model provides a solution to a long-lasting problem of how molecular mobility is enhanced in solid polymers by photoisomerization and provides a tool for a better understanding of the relationship between light absorption and material properties and developing photosensitive polymers for light to mechanical energy transduction.

Optical limiting is the phenomenon widely recognized as the potential application for a protector of human eyes and optical sensors from irradiation with lasers. However, much high optical limiting threshold and less flexibility have restricted such applications. Here, we report that oligothiophene-doped liquid crystals (LCs) function as a low-threshold optical limiter with deformability. Irradiation of dye-doped LCs with a continuous wave (CW) laser beam brings about the formation of diffraction rings, and the number of rings changes depending on the incident light intensity due to their photoinduced molecular reorientation. Utilizing such reorientation enables reversible optical limiting without additional multilayered optical components. Furthermore, softness of LCs allows for the fabrication of the deformable optical limiter; optical limiting due to the molecular reorientation occurs even in largely bent states. The low-threshold and deformable optical limiter based on oligothiophene-doped LCs thus will enable one to develop the protector of eyes and optical sensors from glaring-light-induced damage.

Orbital angular momentum (OAM) of optical vortex can twist azo-polymers to form a micron-scale chiral surface relief, reflecting the helical wavefront of the irradiated optical vortex beam, with the aid of spin angular momentum (SAM). In this work, we present a new approach for light induced chiral surface relief formation, in which chiral surface reliefs of azopolymers with multiple arms are formed by the irradiation of temporally rotating petal beams without OAM, but assisted by the SAM associated with circular polarization. Also, we demonstrate the orientation control of the fabricated multiple-armed chiral surface reliefs in azo-polymers by properly controlling the exposure time.

In colloidal suspensions with nonlinear optical techniques, it is possible to overcome strong scattering effects and form a self-induced waveguide of light. Previous studies of dielectric, metallic, and biological colloidal suspensions show waveguide formation for spherical, elliptical, and disc-like particles. In all the previous works, the particle can be approximated as a spherical particle. In this work, we study light propagation and the possibility to form a waveguide with long helical-shaped particles. In our study, we extract the strawberry DNA using the CTAB protocol, resuspend DNA in DI water, and study the possibility to form biological waveguides in DNA suspensions at different wavelengths. Since extracted DNA are very long helical-shaped strands, which coil with each other, DNA displays a "topologically frustrated" inability to move and can’t form a typical biological waveguide.