Outcome：

2025
We have developed a 3 $\mu$m-band mid-infrared laser capable of exciting OH and CH groups using a different method from the one employed last year. Development of this laser system is currently ongoing.

2024
We have investigated the 3μm mid-infrared fiber laser that can be used for the excitation of OH and CH vibrational modes.

2023
Through the single particle tracking analysis, we evaluate the trapping dynamics by changing the wavelength. The results are published in Optics Express.

2022
We performed opto-thermal trapping of colloidal particles with a 3μm　Er-doped ZBLAN fiber laser. We started from the laser generation of 3μm continuous laser. Water has a strong absorption at 3μm in wavelength due to the O-H vibrational mode. We achieved the trapping with much lower laser power compared to our previous study with the 2 μm laser.

2021
We performed opto-thermal trapping of polystyrene particles with a 2 μm Tm-doped fiber laser. By using the 2 μm　laser, water is directly heated and it enables the trapping of the particles along the temperature gradient.

In this research, we are conducting experiments on next-generation, species-selective optical manipulation using mid-infrared lasers. By utilizing molecular vibrational resonance, we aim to sort molecular species based on their infrared spectra.

Outcome：

2025
We have discovered that the mid-infrared radiation force acting on silica microparticles increases due to the effect of Reststrahlen reflection. This experimental achievement demonstrates that the mid-infrared radiation force depends not only on the imaginary part of the dielectric function but also on its real part.

2024
We found that velocity spectra representing the particle velocity at different wavenumber tightly follow the infrared spectra of those particles by utlizing the tunable mid-infrared lasers.

2023
The particles are sorted based on the absorbance by mid-infrared optical force in the following order: quartz, silica, silicone resin, TPM, PMMA and polystyrene.

2022
We present a mid-infrared optical force chromatography technique that enables precise sorting of microspheres based on their molecular vibrational properties using a mid-infrared quantum cascade laser. A variety of microspheres, including those composed of Si-O-Si bonds, can be separated in accordance with their absorbance values at that laser wavelength.

2021
Optical sorting of silica particles is demonstrated by exciting their vibrational mode with mid-infrared lasers.

2020
We prepared the optical system for mid-infrared optical manipulation.

Outcome：

2025
We have successfully achieved optical trapping of microparticles using a focused mid-infrared beam. Our results clarify that the trapping stiffness, which serves as a value of the optical trapping force, is dependent on the laser wavelength. We will continue these experiments in the next year.

2024
We demonstrated the experiment of mid-infrared optical tweezers. We build the optical microscope with mid-infrared laser. Under certain condition, the target particles were assembled at the glass solution interface by the mid-infrared laser.

中赤外領域における局在電場を利用しナノ粒子安定的に光捕捉することが目的である。

Outcome：

2025
金属ナノ構造体の作製も開始した。概ねFDTDシミュレーションに似たナノ構造体を電子線描画装置等を用いて作製することができた。グラフェンのナノ構造体作製に関しては、クリーンルームにおいて作製を開始している。

2024
FDTDシミュレーションを用いて、ナノ粒子捕捉へ向けたグラフェンナノ構造体の設計を行った。