Search results for "Laser line"
showing 10 items of 95 documents
Simple digital system for tuning and long-term frequency stabilization of a CW Ti:Sapphire laser
2015
We have implemented a simple digital system for long-term frequency stabilization and locking to an arbitrary wavelength of the single-frequency ring CW Ti:Sapphire laser. This system is built using two confocal Fabry-Perot cavities, one of which is used to narrow the short-term linewidth of the laser and the other to improve the long-term stability of the laser frequency. The length of the second cavity is stabilized using the radiation from an external-cavity diode laser locked to an atomic transition. Our system is an improvement of a commercial Tekhnoscan laser lock. This system has been successfully used in our experiments on high-resolution laser spectroscopy of ultracold rubidium Ryd…
Fiber Ring Laser Operated by Dynamic Local Phase Shifting of a Chirped Grating
2009
An ultranarrow linewidth erbium-doped fiber ring laser is presented. It is based on the filtering properties of a phase-shifted chirped fiber Bragg grating, which is inserted inside the cavity of the laser. A dynamic control of the phase shifting, which is induced by a magnetostrictive transducer, permits both tunable continuous-wave and actively Q-switched operation. The use of a chirped grating overcomes the limitations imposed by the narrow spectra of uniform gratings observed in previously reported ring lasers based on intracavity transmission filters.
Tunable narrowband fiber laser with feedback based on whispering gallery mode resonances of a cylindrical microresonator.
2013
Narrowband filtering based on whispering gallery modes of a slightly tapered cylindrical optical microresonator was used to implement a tunable narrowband erbium-doped fiber laser. The laser can be set to emit a single longitudinal cavity mode (single frequency), although the laser cavity is a few meters long. In the single-frequency regime the laser can emit a maximum power of 0.380 mW with a linewidth <35 kHz and a signal-to-noise ratio exceeding 50 dB. Tunability is achieved by sliding the excitation point along the microcylinder. A tuning range of 1.16 nm is demonstrated.
4W continuous-wave narrow-linewidth tunable solid-state laser source at 546nm by externally frequency doubling a ytterbium-doped single-mode fiber la…
2009
A high-power continuous-wave coherent light source at 545.5nm is described. We use 8.3W from a solid-state ytterbium-doped single-mode fiber oscillator/amplifier system as input into an external frequency doubling stage. This system produces up to 4.1 W of stable green single-frequency laser radiation. We characterize the light source by performing absorption spectroscopy on iodine across the full tuning range of the fiber laser and saturation spectroscopy on one strong iodine line of the doppler-broadened spectrum.
High resolution CARS spectrum and analysis of the v1bandQ-branch of carbon dioxide
1988
High resolution coherent anti-Stokes Raman spectroscopy (CARS) has been applied to the study of the Q-branch of the fundamental vibrational v 1 band of CO2 in the Fermi resonance region near 1285·5 cm-1. Thanks to the use of high spectral quality (linewidth = 6 MHz) injection-locked flashlamp-pumped dye lasers, it was possible to resolve this band for the first time. The spectrum was recorded at a pressure of 5 kPa (37·5 Torr) at room temperature. We measured the line positions and collisional widths for the transitions with J values from 8 to 38. Our experimental line positions are in excellent agreement with those derived from molecular constants given on the literature. The observed line…
Very narrow-bandwidth tunable infrared difference frequency generation with injection-locked dye lasers
1989
Two flashlamp pumped dye lasers of very high spectral quality are mixed in a LiIO3 crystal to generate a tunable infrared beam through the difference frequency mixing. Thanks to the injection-locking process of the pulsed dye lasers leading to a linewidth of 6 MHz with peak powers of about 10 kW, we obtain an IR beam tunable from 3.5 to 5.9 μm with a peak power of 40 W and a linewidth of 9 MHz. As an application we present a spectrum of N2O obtained by differential absorption near 1880 cm−1. The lines of thisQ-branch are Doppler limited at the working pressure (102 Pa).
Polariton response in the presence of Brownian dissipation from molecular vibrations
2020
We study the elastic response of a stationarily driven system of a cavity field strongly coupled with molecular excitons, taking into account the main dissipation channels due to the finite cavity linewidth and molecular vibrations. We show that the frequently used coupled oscillator model fails in describing this response especially due to the non-Lorentzian dissipation of the molecules to their vibrations. Signatures of this failure are the temperature dependent minimum point of the polariton peak splitting, uneven polariton peak height at the minimum splitting, and the asymmetric shape of the polariton peaks even at the experimentally accessed "zero-detuning" point. Using a rather generi…
Temperature dependence of the E2h phonon mode of wurtzite GaN/AlN quantum dots
2008
Raman scattering has been used to study the temperature dependence of the frequency and linewidth of the E2h phonon mode of GaN/AlN quantum dot stacks grown on 6H-SiC. The evolution of the nonpolar phonon mode was analyzed in the temperature range from 80 to 655 K for both quantum dots and barrier materials. The experimental results are interpreted by comparison with a model that takes into account symmetric phonon decay and the different thermal expansions of the constituents of the heterostructure. We find a small increase in the anharmonic parameters of the phonon modes in the heterostructure with respect to bulk. jorbumar@alumni.uv.es Alberto.Garcia@uv.es Ana.Cros@uv.es
Synthesis of Nanoparticles
2012
In this chapter I describe the synthetic methods for the particles used in this work. Initially bare gold nanorods are synthesized , which are used to investigate continuously the growth of bigger nanoparticles and the protein-membrane interaction on a single particle level . To reduce the single particle linewidth and therefore to increase the sensitivity on changes in the refractive index , these rods are coated with a thin silver shell . Another method to increase the sensitivity of nanoparticles is to produce hollow rod-shaped nanorattles, which were synthesized by Yuriy Khalavka . To investigate the polarization depend scattering spectra of different shapes with the RotPOL setup , diff…
Electron paramagnetic resonance of Gd3 in TlGdSe2
2003
Electron paramagnetic resonance has been studied on the polycrystalline sample of the layer compound TlGdSe 2 . When the temperature is lowered from room temperature the linewidth reaches a shallow minimum near 60 K and then decreases rapidly below 15 K. From the two-dimensional molecular field model two exchange constants J 1 and J 2 with the nearest and next nearest neighbors were estimated. The calculated high-temperature limit of the linewidth (341 mT) is in fair agreement with the experimental value (314 mT). It may be slightly improved after taking into account the preferred orientation of the sample.