Absolute Single Ion Thermometry

We describe and experimentally implement a single-ion local thermometry technique with absolute sensitivity adaptable to all laser-cooled atomic ion species. The technique is based on the velocity-dependent spectral shape of a quasi-dark resonance tailored in a J $\rightarrow$ J transition such that the two driving fields can be derived from the same laser source leading to a negligible relative phase shift. We validated the method and tested its performances in an experiment on a single 88 Sr + ion cooled in a surface radio-frequency trap. We first applied the technique to characterise the heating-rate of the surface trap. We then measured the stationary temperature of the ion as a function of cooling laser detuning in the Doppler regime. The results agree with theoretical calculations, with an absolute error smaller than 100 $\mu$K at 500 $\mu$K, in a temperature range between 0.5 and 3 mK and in the absence of adjustable parameters. This simple-to-implement and reliable method opens the way to fast absolute measurements of single-ion temperatures in future experiments dealing with heat transport in ion chains or thermodynamics at the single-ion level

Strong quantum correlations in four wave mixing in 85^{85}Rb vapor

We study quantum intensity correlations produced using four-wave mixing in a room-temperature rubidium vapor cell. An extensive study of the effect of the various parameters allows us to observe very large amounts of non classical correlations.Comment: 8 pages and 8 figures; work presented at the SPIE Photonics Europe conference (Brussels, 2010

Isotope shifts of natural Sr+ measured by laser fluorescence in a sympathetically cooled Coulomb crystal

We measured by laser spectroscopy the isotope shifts between naturally-occurring even-isotopes of strontium ions for both the 5s\,\,^2S_{1/2}\to 5p\,\,^2P_{1/2} (violet) and the 4d\,\,^2D_{3/2}\to 5p\,\,^2P_{1/2} (infrared) dipole-allowed optical transitions. Fluorescence spectra were taken by simultaneous measurements on a two-component Coulomb crystal in a linear Paul trap containing $10^3$--$10^4$ laser-cooled Sr$^+$ ions. The isotope shifts are extracted from the experimental spectra by fitting the data with the analytical solution of the optical Bloch equations describing a three-level atom in interaction with two laser beams. This technique allowed us to increase the precision with respect to previously reported data obtained by optogalvanic spectroscopy or fast atomic-beam techniques. The results for the 5s\,\,^2S_{1/2}\to 5p\,\,^2P_{1/2} transition are $\nu_{88}-\nu_{84}=+378(4)$ MHz and $\nu_{88}-\nu_{86}=+170(3)$ MHz, in agreement with previously reported measurements. In the case of the previously unexplored 4d\,\,^2D_{3/2}\to 5p\,\,^2P_{1/2} transition we find $\nu_{88}-\nu_{84}=-828(4)$ MHz and $\nu_{88}-\nu_{86}=-402(2)$ MHz. These results provide more data for stringent tests of theoretical calculations of the isotope shifts of alkali-metal-like atoms. Moreover, they simplify the identification and the addressing of Sr$^+$ isotopes for ion frequency standards or quantum-information-processing applications in the case of multi-isotope ion strings.Comment: 19 pages; 5 figures; accepted on Phys. Rev. A (http://pra.aps.org/

Spectral resolution and sampling issues in Fourier-transform spectral interferometry

International audienceWe investigate experimental limitations in the accuracy of Fourier-transform spectral interferometry, a widely used technique for determining the spectral phase difference between two light beams consisting of, for example, femtosecond light pulses. We demonstrate that the spectrometer's finite spectral resolution, pixel aliasing, and frequency-interpolation error can play an important role, and we provide a new and more accurate recipe for recovering the spectral phase from the experimental data. Cop. 2000 Optical Society of Americ

Amplitude and phase measurements of femtosecond pulses shaped using spectral hole burning in free-base naphthalocyanine-doped films.

In this work we use a technique of spectroscopy adapted for measuring the amplitude and phase of photon echo signals [7] produced by diffraction of a fs pulse on a spectral hologram. We also improved the technique in terms of spectral resolution in order to measure photon echoes delayed by a few tens of picoseconds. Our study is focused on measuring the coherence time of the sample using a photon echo experiment in the photochemically accumulated regime and on demonstrating the pulse-shaping and time-reversal potentialities of our photo-sensitive material. Spectral holograms are formed through persistent spectral hole burning using a sequence of 2 pump pulses separated by a time delay, in a collinear geometry. The sample is a free base naphtalocyanine embedded in polyvinylbutyral (H2NPc/PVB). The absorption peaks at 783 nm and is 20 nm large (FWHM). Our laser source is a 15-fs, 100MHz, Ti:S oscillator

Amplitude and phase measurements of femtosecond pulses shaped using spectral hole burning in free-base naphthalocyanine-doped films.

In this work we use a technique of spectroscopy adapted for measuring the amplitude and phase of photon echo signals [7] produced by diffraction of a fs pulse on a spectral hologram. We also improved the technique in terms of spectral resolution in order to measure photon echoes delayed by a few tens of picoseconds. Our study is focused on measuring the coherence time of the sample using a photon echo experiment in the photochemically accumulated regime and on demonstrating the pulse-shaping and time-reversal potentialities of our photo-sensitive material. Spectral holograms are formed through persistent spectral hole burning using a sequence of 2 pump pulses separated by a time delay, in a collinear geometry. The sample is a free base naphtalocyanine embedded in polyvinylbutyral (H2NPc/PVB). The absorption peaks at 783 nm and is 20 nm large (FWHM). Our laser source is a 15-fs, 100MHz, Ti:S oscillator

Amplitude and phase measurements of femtosecond pulses shaped using spectral hole burning in free-base naphthalocyanine-doped films.

International audienceIn this work we use a technique of spectroscopy adapted for measuring the amplitude and phase of photon echo signals [7] produced by diffraction of a fs pulse on a spectral hologram. We also improved the technique in terms of spectral resolution in order to measure photon echoes delayed by a few tens of picoseconds. Our study is focused on measuring the coherence time of the sample using a photon echo experiment in the photochemically accumulated regime and on demonstrating the pulse-shaping and time-reversal potentialities of our photo-sensitive material. Spectral holograms are formed through persistent spectral hole burning using a sequence of 2 pump pulses separated by a time delay, in a collinear geometry. The sample is a free base naphtalocyanine embedded in polyvinylbutyral (H2NPc/PVB). The absorption peaks at 783 nm and is 20 nm large (FWHM). Our laser source is a 15-fs, 100MHz, Ti:S oscillator

Coherent broadband pulse shaping in the mid infrared

International audienceWe demonstrate broadband infrared pulse shaping by difference-frequency mixing of two visible phase-locked linearly chirped pulses in GaAs. Control of the temporal profile of the emitted field is achieved through this direct tailoring of the exciting visible intensity. The results are in agreement with a simulation with no adjustable parameter. (C) 2001 Optical Society of America

Amplitude and phase measurements of femtosecond pulses shaped using spectral hole burning in free-base naphthalocyanine-doped films.

In this work we use a technique of spectroscopy adapted for measuring the amplitude and phase of photon echo signals [7] produced by diffraction of a fs pulse on a spectral hologram. We also improved the technique in terms of spectral resolution in order to measure photon echoes delayed by a few tens of picoseconds. Our study is focused on measuring the coherence time of the sample using a photon echo experiment in the photochemically accumulated regime and on demonstrating the pulse-shaping and time-reversal potentialities of our photo-sensitive material. Spectral holograms are formed through persistent spectral hole burning using a sequence of 2 pump pulses separated by a time delay, in a collinear geometry. The sample is a free base naphtalocyanine embedded in polyvinylbutyral (H2NPc/PVB). The absorption peaks at 783 nm and is 20 nm large (FWHM). Our laser source is a 15-fs, 100MHz, Ti:S oscillator