RIKEN Center for Advanced Photonics

Video-rate volumetric chemical imaging via mid-infrared photothermal optical diffraction tomography

Abstract Label-free vibrational microscopy provides chemically specific access to cellular structures, yet quantitative volumetric imaging of intracellular dynamics remains challenging on subsecond timescales. Here, we demonstrate video-rate mid-infrared photothermal optical diff...

High-harmonic Generation Spectroscopy in van der Waals Materials: Accessing Bloch Wavefunctions and Their Scattering Processes

High-harmonic generation (HHG) — an extreme nonlinear response to strong light fields — has emerged as a promising tool for probing femtosecond-to-attosecond electron dynamics in crystalline solids. This special topic article presents a perspective on how HHG spectroscopy has bee...

Towards intense single-digit attosecond pulses with a 100-mJ-class mid-infrared sub-cycle laser

The duration of isolated attosecond pulses created via high-order harmonic generation is determined by the number of optical cycles in the driving laser. Achieving shorter attosecond soft x-ray pulses requires minimizing the number of cycles while maintaining a high pulse energy....

Wave vortices around oscillating subwavelength holes: Water-wave observation

We consider a two-dimensional wave system containing a subwavelength hole, such as an aperture in an interface supporting surface electromagnetic or acoustic waves or an island in a fluid surface sustaining gravity-capillary waves. Recent studies have revealed the emergence of pr...

Observation of near-infrared fluorescence from within biological specimens using X-ray light-sheet microscopy for deep-tissue imaging

Abstract Light-sheet fluorescence microscopy enables rapid three-dimensional imaging of biological specimens with low phototoxicity and high signal-to-noise ratio, but its imaging depth is limited by optical scattering and absorption in tissue. X-ray light-sheet microscopy, terme...

REAP1/AtSWAP70 integrates RAB5 and ROP signalling during sexual reproduction

Small GTPases of the Ras superfamily are critical regulators of diverse cellular processes. While crosstalk between their signalling pathways has been documented in animals, similar mechanisms remain unexplored in plants, where small GTPases have undergone unique evolutionary div...

Phase-shift Instanton Approach to Tunneling Duality in Read–Rezayi State

We study the duality between quasi-particle and electron tunneling in point-contact geometries of fractional quantum Hall states. To treat non-Abelian edge operators, we introduce a “phase-shift instanton” that incorporates phase factors from primary fields into the instanton gas...

Strong coupling between RF photons and plasmons of electrons on liquid helium

Plasmons, arising from the collective motion of electrons, can interact strongly with electromagnetic fields or photons; this capability has been exploited across a broad range of applications, from chemical reactivity to biosensing. Recently, there has been growing interest in p...

Microsecond Barrier-Crossing Collapse in Cytochrome c Folding Revealed by Two-Dimensional Fluorescence Lifetime Correlation Spectroscopy

Abstract Protein folding is initiated with a volume contraction called collapse. While the microsecond collapse of horse cyt c has been intensely studied, its molecular mechanism remains elusive. To characterize the structural change, we prepared three cyt c variants labeled with...

Cryogenic time-division-multiplexed voltage control for scalable trapped-ion quantum processors

Trapped-ion quantum computers based on the quantum charge-coupled device architecture require on the order of ten trap electrodes per qubit, making the number of vacuum feedthroughs a bottleneck at the system scale. Time-division multiplexed (TDM)-based voltage control for trap e...

Submicrometer focusing of isolated attosecond XUV pulses approaching 1016 W/cm2

We demonstrate submicrometer focusing of isolated attosecond pulses (IAPs) in the extreme ultraviolet (XUV) region using a custom ellipsoidal mirror. The obtained focal spot sizes were verified using knife-edge measurements with a sharp silicon edge, confirming reproducible dimen...