Search results for "Laser line"
showing 10 items of 95 documents
The effect of high-In content capping layers on low-density bimodal-sized InAs quantum dots
2013
[EN] The structural and morphological features of bimodal-sized InAs/(In) GaAs quantum dots with density in the low 10(9) cm(-2) range were analyzed with transmission electron microscopy and atomic force microscopy and were related to their optical properties, investigated with photoluminescence and time-resolved photoluminescence. We show that only the family of small quantum dots (QDs) is able to emit narrow photoluminescence peaks characteristic of single-QD spectra; while the behavior of large QDs is attributed to large strain fields that may induce defects affecting their optical properties, decreasing the optical intensity and broadening the homogeneous linewidth. Then, by using a rat…
Polarized multiplex coherent anti-Stokes Raman scattering using a picosecond laser and a fiber supercontinuum
2011
International audience; We perform multiplex coherent anti-Stokes Raman scattering (CARS) micro-spectroscopy with a picosecond pulsed laser and a broadband supercontinuum (SC) generated in photonic crystal fiber. CARS signal stability is achieved using an active fiber coupler that avoids thermal and mechanical drifts. We obtain multiplex CARS spectra for test liquids in the 600–2000 cm−1 spectral range. In addition we investigate the polarization dependence of the CARS spectra when rotating the pump beam linear polarization state relative to the linearly polarized broad stokes SC. From these polarization measurements we deduce the Raman depolarization ratio, the resonant versus nonresonant …
High-power pulsed dye laser with Fourier-limited bandwidth
1986
A high-peak-power, narrow-linewidth light source with a homogeneous beam profile has been constructed by modifications to a commercially available pulsed-dye-laser system. Output pulses of up to 10 mJ were generated with linewidths of about 50 MHz for 12-nsec pulses. The pulse-to-pulse frequency stability was better than the linewidth, and the center frequency could be scanned over a frequency range of 142.5 GHz at a wavelength of 600 nm. The performance of the system was demonstrated by observing the 6s2 1S0–6s7s1S0 transition in atomic mercury at 2λ = 312.8 nm and the 6s2S1/2–8s2S1/2 transition in atomic gold at 2λ = 308.9 nm using up to 1 mJ of frequency-doubled output for two-photon non…
Investigation of electron transfer between single plasmon and graphene by dark field spectroscopy
2020
Abstract We investigated the electron transfer time between single plasmonic gold nanoparticles and graphene with our home-build spectral imaging dark-field microscope. The process of electron transfer is supposed to be shuttling of hot electrons on the nanoparticle-graphene interface, resulting in a slight broadening of the scattering spectrum. For detecting the minor spectrum broadening, we firstly characterized our setup systematically and then calibrated its intrinsic error. We found the mechanism of a common but normally neglected setup error, scattering spectrum broadening, which is caused by the bandwidth of the incident light and could exist in most fast dark-field microscopy setups…
Polychromatic, continuous-wave mirrorless lasing from monochromatic pumping of cesium vapor
2019
We report on studies of simultaneous continuous-wave mirrorless lasing on multiple optical transitions, realized by pumping hot cesium vapor with laser light resonant with the 6$S_{1/2}\rightarrow 8$P$_{3/2}$ transition. The multiplicity of decay paths for the excited atoms to their ground state is responsible for the emergence of lasing in a number of transitions, observed here in at least seven wavelengths in the infrared (IR), and at two wavelengths in the blue. We study the properties of the fields generated in the cesium vapor, such as optical power, directionality and optical linewidth.
Continuously tunable diamond Raman laser for resonance ionization experiments at CERN
2019
We demonstrate a highly efficient, continuously tunable, diamond Raman laser operating in the blue region of the spectrum. The linewidth and tunability characteristics of a frequency-doubled Ti:Sapphire laser were transferred directly to the Stokes output, offering great potential for spectroscopic applications using an all-solid-state platform.
Raman scattering inβ-ZnS
2004
The first- and second-order Raman spectra of cubic ZnS $(\ensuremath{\beta}$-ZnS, zinc-blende) are revisited. We consider spectra measured with two laser lines for samples with different isotopic compositions, aiming at a definitive assignment of the observed Raman features and the mechanisms which determine the linewidth of the first order TO and LO Raman phonons. For this purpose, the dependence of the observed spectra on temperature and pressure is investigated. The linewidth of the TO phonons is found to vary strongly with pressure and isotopic masses. Pressure runs, up to 15 GPa, were performed at 16 K and 300 K. Whereas well-defined TO Raman phonons were observed at low temperature in…
Continuously tunable diamond Raman laser for resonance laser ionization.
2019
We demonstrate a highly efficient, tunable, ∼5 GHz line- width diamond Raman laser operating at 479 nm. The diamond laser was pumped by a wavelength-tunable intra- cavity frequency-doubled titanium sapphire (Ti:Sapphire) laser operating at around 450 nm, at a repetition rate of 10 kHz with a pulse duration of 50 ns. The Raman reso- nator produced a continuously tunable output with high stability, high conversion efficiency (28%), and beam quality (M$^{2}$ <1.2). We also demonstrate that the linewidth and tunability of the pump laser is directly transferred to the Stokes output. Our results show that diamond Raman lasers offer great potential for spectroscopic applications, such as resonance…
Homogeneous and inhomogeneous broadening in single perovskite nanocrystals investigated by micro-photoluminescence
2021
Abstract Metal halides with perovskite crystalline structure have given rise to efficient optoelectronic and photonic devices. In the present work, we have studied the light emission properties of single CsPbBr3 and CsPbI3 semiconductor perovskite nanocrystals (PNCs), as the basis for a statistical analysis of micro-photoluminescence (micro-PL) spectra measured on tens of them. At room temperature, the linewidth extracted from PL spectra acquired in dense films of these nanocrystals is not very different from that of micro-PL measured in single nanocrystals. This means that the homogeneous linewidth due to exciton-phonon interaction is comparable or larger than the inhomogeneous effect asso…
Broadband Fabry–Pérot Resonator From Zerodur for Laser Stabilisation Below 1KHZ Linewidth With < 100 HZ/S Drift and Reduced Sensitivity to Vibrati…
2015
Abstract Here we demonstrate the results of creating a two-mirror Fabry-Pérot resonator (FPR) that allows achieving the spectral width of a stabilised laser line below 1 kHz. It had low expansion Zerodur spacer and broadband high reflectance mirrors (99.85% in the range of 630 to 1140 nm). FPR was vertically mid-plane mounted for reduced sensitivity to vibrations and included in two shields inside a vacuum chamber to lower temperature fluctuations. Peltier element was used for temperature stabilisation at zero-expansion temperature. Pound-Drever-Hall (PDH) technique was applied. The signal from FPR was compared to ultra-stable signal (of about 1 Hz linewidth) to form a beat note signal. For…