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We present results on attosecond transient absorption in small molecules. Ultrafast relaxation dynamics in nitrogen can be temporally resolved by combining an isolated attosecond pulse and an intense synchronized carrier-envelope-phase stable infrared pulse. The lifetime of the different Fano resonances can be retrieved.
We report a highly-sensitive technique to obtain mid-infrared spectra with nanoscale spatial resolution via detecting a mechanical force exerted by vibrating molecules on an atomic force microscope tip. Sub-monolayer sensitivity is demonstrated.
We present the measurement of χ(3) nonlinearity of Green Fluorescent Protein. The nonlinear index is n2 = 10−19m2/W, opening the possibility of using genetically engineerable and naturally occuring proteins in cells as a source of four wave mixing experiments.
We study the time- and spectrally-resolved exciton dynamics of a few-layer molybdenum disulfide using ultrafast optical pump-probe spectroscopy. We find that the carrier induced broadening significantly influence on the band-edge transmission spectra even with small carrier densities.
The influence of fs-pulse train period on the Au nanoparticles production was studied. Using a pulse shaping technique, the period was tunned in order to match Raman resonances that enhance the Au nanoparticle formation process.
A design method for critically coupling into a weakly absorbing Si waveguide photonic crystal cavity is presented. Using this method, an ultra-compact Si+ implanted waveguide photodiode is designed with a factor of 240 increase in absorption.
We theoretically demonstrate that if pump powers are kept low enough to suppress multi-pair events in integrated photon pair generation via spontaneous four-wave mixing, many other nonlinear effects are often also constrained to negligible levels.
This work reports on the attosecond real-time observation of the electron processes [1] underlying the ability of ultrastrong few-cycle laser pulses to turn a dielectric solid from an insulating into a conducting state [2].
Isolated attosecond pulses with continuum spectra extending below 15 eV are used to probe the sub-cycle energy shifts and splitting of helium excited states. Additionally, new absorption features appear far from the 1snp absorption lines.
We demonstrate an optical antenna absorber with unity absorption based on gold nanostrip antenna with optical back mirror. Indium Tin Oxide is used as the active material to electrically tune the optical spectra.
Reduction of absorption coefficient due to heat-up in hot-band pumped Nd:YAG was studied, and it was much smaller than cold-band pumping. In addition, the necessity of correction in the traditional model for line-bandwidth became clear.
We rigorously determine the effect of parasitic loss on the achievable absorption enhancement in nanophotonic, plasmonic light trapping schemes. We show that, even in the presence of parasitic loss, opportunities exist to exceed conventional limits.
We investigate-light trapping in thin-film crystalline silicon solar cells with rough interfaces and engineered disordered photonic structures. The general aspects of the optical properties are discussed, demonstrating broad band absorption close to the Lambertian limit.
We experimentally demonstrate two-photon Doppler free interactions on a chip-scale platform consisting of a silicon nitride waveguide integrated with rubidium vapor cladding. We obtain absorption lines having widths of 300 MHz, using low power levels.
We detect both pulsed and CW IR light using uncooled GaN or GaAs photodiodes using extremely-nondegenerate two-photon-absorption (2PA) which shows large enhancement over degenerate 2PA. Urbach-tail absorption limits the signal-to-noise ratio for CW detection.
We report design and experimental realization of an organic PV device structure to trap incident light in all polarization states utilizing 1D, long-pitch (> 1000 n m) gratings. Polarization diversity was achieved by balancing the plasmonic and guided mode-based light trapping routes between different polarization states. The experiment showed strong enhancements in absorption in all polarization...
Co-seeding method at 1.0μm was applied in order to scale up the 1.5μm output power of a 976nm pumped single-frequency Er:Yb-codoped triple clad fiber amplifier to a maximum output power of 50W.
A previously unreported correlation is presented between reduced values of unsaturated absorption at the laser gain peak and low measured time-bandwidth-product (TBP) values of optical pulses emitted from monolithic quantum dot passively mode-locked lasers.
We propose a hyperbolic metamaterial waveguide to realize a highly efficient rainbow trapping effect, which can be used to develop practical on-chip optical super absorbers with a tunable absorption band.
We measured ultrafast relaxation in a deliberately heterogeneous ensemble of carbon nanotubes. Complex differential transmission signatures revealed competition between ground state bleaching and excited state absorption from nanotubes of different chiralities.
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