Broadband on-chip optical frequency combs (OFCs) are important for expanding the functionality of photonic integrated circuits. Here, we demonstrate a huge local optical nonlinearity enhancement using graphene. A waveguide is decorated with graphene by precisely manipulating graphene's area and position. Our approach simultaneously achieves both an… (More)
Low-noise millimetre-wave signals are valuable for digital sampling systems, arbitrary waveform generation for ultra-wideband communications, and coherent radar systems. However, the phase noise of widely used conventional signal generators (SGs) will increase as the millimetre-wave frequency increases. Our goal has been to improve commercially available… (More)
Most future information processing techniques using electron spins in non-magnetic semiconductors will require both the manipulation and transfer of spins without their coherence being lost. The spin-orbit effective magnetic field induced by drifting electrons enables us to rotate the electron spins in the absence of an external magnetic field. However, the… (More)
The hybridization of semiconductor optoelectronic devices and nanomechanical resonators provides a new class of optomechanical systems in which mechanical motion can be coupled to light without any optical cavities. Such cavity-less optomechanical systems interconnect photons, phonons and electrons (holes) in a highly integrable platform, opening up the… (More)
In many atomic, molecular and solid systems, Lorentzian and Fano profiles are commonly observed in a broad research fields throughout a variety of spectroscopies. As the profile structure is related to the phase of the time-dependent dipole moment, it plays an important role in the study of quantum properties. Here we determine the dipole phase in the… (More)
We report carrier-envelope offset beat detection (52-dB signal-to-noise ratio at 100-kHz resolution bandwidth) with a common-path 2f-to-3f self-referencing interferometer with a dual-pitch periodically poled lithium niobate ridge waveguide.
We demonstrate the broadest on-chip supercontinuum generation, spanning more than 2/3-octave (1300-2200 nm) bandwidth, with an 80-fs laser pulse in the 1.5-μm band by controlling dispersion in a 0.9-cm-long Si-wire waveguide.
Toward quantum information applications, we control the interactions between Er ions by alloying epitaxial Er<sub>2</sub>O<sub>3</sub> with scandium and suppress energy transfer and inhomogeneous broadening of Stark levels in the intra-4f band of Er ions.
We characterized field emission from autoionization transition in atomic neon stimulated by isolated attosecond field. The spectrum of the emitted field broadens approximately 1 eV bandwidth, which corresponds to shorter than 2.5 fs-duration.
980 nm pump laser diode modules with a failure rate as low as 30 FIT for 27 years lifetime have been successfully developed. These are the first undersea-qualified 980 nm pump sources and are to be used in upcoming transoceanic submarine systems.