Femtosecond-laser-induced optical confinement with ping-pong motion.

We introduce a novel method using a kilohertz (kHz) amplified 800 nm laser for the first experimental confinement of microparticles within a single beam. This study demonstrates that high-energy kHz pulses can confine 1-μm-radius polystyrene beads in water within ∼26 μm. This approach utilizes the unique properties of high-energy pulsed lasers, distinct from continuous-wave and megahertz pulsed lasers traditionally used in optical trapping.

Precise Nanoparticle Manipulation Using Femtosecond Laser Trapping.

Optical tweezers use strongly focused light for trapping, characterizing, and manipulating objects in the microscopic and nanoscopic regimes. However, fully understanding optical trapping at the nanoscale remains a significant challenge. This holds importance because the nanoscale is the frontier for numerous promising advancements, ranging from enhancing single-molecule investigations in biology to developing hybrid devices for nanoelectronics and photonics and exploring fundamental quantum phenomena in opto-mechanics.

Reversible open-closed conformational switching of nano-size metalloporphyrin dimers triggered by light and temperature.

The current work demonstrates the reversible control of substantial molecular motion in 'nano-sized' molecules, where two structural isomers can 'open' and 'close' their cavities in response to light or heat. The isomers differ widely in their photophysical properties, including colour, polarity, two-photon absorption and π-conjugation, and can easily be separated through column chromatography and thus have wide applicability.