surface-enhanced raman spectroscopy (sers) is a promising tool in the analytical science because it provides good selectivity and sensitivity without the labeling process required by fluorescence detection. this technique consists of locating the target analyte on nanometer range of roughed au-nanoparticles. the presence of the metal nanoparticles provides a tremendous enhancement to the result...

We measure the effects of phonon confinement on the Raman spectra of silicon nanowires (SiNWs). We show how previous reports of phonon confinement in SiNWs and nanostructures are actually inconsistent with phonon confinement, but are due to the intense local heating caused by the laser power used for Raman measurements. This is peculiar to nanostructures, and would require orders of magnitude h...

Introduction Scattering of optical radiation by materials is a topic that has received much attention over the past 100 years. One particular type, Raman scattering, was first observed by C.V. Raman in 1928, and since then this inelastic scattering process has found many uses in basic and applied science. Raman scattering can be used to make spectroscopic measurements, or exploited to build Ram...

Raman scattering is a rare event. It is only the extreme brightness of a focused laser radiation that makes Raman spectroscopy practical. Thus, since the laser beam is not materially affected by the interaction, it should be possible to pass the same laser beam through a sample multiple times with little attenuation of the laser power. We have accomplished this by means of a probe design in whi...

This work reports on the first time experimental investigation of temperature field inside silicon substrates under particle-induced near-field focusing at a sub-wavelength resolution. The noncontact Raman thermometry technique employing both Raman shift and full width at half maximum (FWHM) methods is employed to investigate the temperature rise in silicon beneath silica particles. Silica part...

Gas-phase laser Raman spectroscopy has recently been adopted to determine the concentrations of relevant gaseous species within the anode flow channel with high spatial and temporal resolution during operation at technically relevant operating conditions. The paper describes the configuration of an optically accessible SOFC, the laser system and optical setup for 1 D Raman spectroscopy as well ...

Confocal micro-Raman spectroscopy is used as a sensitive tool to study the nature of laser-induced defects in single-layer graphene. Appearance and drastic intensity increase of D- and D' modes in the Raman spectra at high power of laser irradiation is related to generation of structural defects. Time- and power-dependent evolution of Raman spectra is studied. The dependence of relative intensi...

The dissipative soliton regime is one of the most advanced ways to generate high-energy femtosecond pulses in mode-locked lasers. On the other hand, the stimulated Raman scattering in a fibre laser may convert the excess energy out of the coherent dissipative soliton to a noisy Raman pulse, thus limiting its energy. Here we demonstrate that intracavity feedback provided by re-injection of a Ram...

Resonant Raman spectroscopy (RRS) is a very useful tool to study physical properties of materials since it provides information about excitons and their coupling with phonons. We present in this work a RRS study of samples of WSe2 with one, two, and three layers (1L, 2L, and 3L), as well as bulk 2H-WSe2, using up to 20 different laser lines covering the visible range. The first- and second-orde...

The principle of all-silicon Raman lasers for an output wavelength of 1.3 μm is presented, which employs quasi-phase-matched structures and resonators to enhance the output power. 1.3-μm laser beams for GE-PONs in FTTH systems generated from a silicon device are very important because such a silicon device can be monolithically integrated with the silicon planar lightwave circuits (Si PLCs) use...