From Nanosecond Photochemistry to Optical Force Chemistry: My Journey

Abstract

Laser was invented in 1960 and soon introduced to chemistry research. We started time‐resolved spectroscopy and photochemistry and initial trial was focused to nanosecond and then picosecond electronic absorption spectroscopy for studying molecular electronic excited states, charge separation in molecular complexes, and intermolecular electron transfer in solution. We considered that not only time‐resolved but also space‐resolved chemistry would be important for future laser‐based chemistry and combined pulsed lasers with optical microscopes. Spectroscopy, photochemistry, ablation, and spatial arrangement of single microparticles and microdroplets in solution were carried out. Further we shifted from micro to nano and opened a new field covering spectroscopy, ablation, phase transition, crystallization, patterning, and fabrication. The progress is summarized and discussed as time‐resolved nano spectroscopy, ablation nano dynamics, and optical force chemistry.

Application of optical tweezers in cardiovascular research: More than just a measuring tool

“…Thus, when light hits an object, force is exerted, which is known as “radiation pressure.” These optical forces are so minute that the mere experimental observation of them in the 1900s was revolutionary ( Lebedew, 1901 ), and no one at that time could have recognized their significance. In the 1960s, the invention of lasers enabled focusing an intense amount of coherent light in a small area ( Masuhara, 2021 ). This inspired Arthur Ashkin, a nuclear physics PhD graduate, to consider the otherwise overlooked practicality of optical forces: theoretically, if light was intense enough and the particle was small enough, the optical force exerted on the particle would be able to accelerate the particle markedly.…”