Manuel Joffre

• École Polytechnique

ADASOPS pump-probe spectroscopy is a multi-timescale technique that is spreading rapidly especially in the field of biomolecule dynamics. Based on slight variations of the laser repetition rate, it is simple to implement and can cover a time range extending from a hundred femtoseconds to a millisecond or more. We have studied the energy fluctuation...

We present a phase-modulated approach for ultrabroadband Fourier transform electronic spectroscopy. To overcome the bandwidth limitations and spatial chirp introduced by acousto-optic modulators (AOMs), pulses from a 1 µm laser are modulated using AOMs prior to continuum generation. This phase modulation is transferred to the continuum generated in...

In fatty acid photodecarboxylase (FAP), light‐induced formation of the primary radical product RCOO⋅ from fatty acid RCOO⁻ occurs in 300 ps, upon which CO2 is released quasi‐immediately. Based on the hypothesis that aliphatic RCOO⋅ (spectroscopically uncharacterized because unstable) absorbs in the red similarly to aromatic carbonyloxy radicals suc...

In fatty acid photodecarboxylase (FAP), light‐induced formation of the primary radical product RCOO● from fatty acid RCOO– occurs in 300 ps, upon which CO2 is released quasi‐immediately. Based on the hypothesis that aliphatic RCOO● (spectroscopically uncharacterized because unstable) absorbs in the red similarly to aromatic carbonyloxy radicals suc...

We demonstrate that chirped pulse up-conversion (CPU), a method routinely used with systems based on 1-kHz Titanium:Sapphire lasers, can be extended to a repetition rate of 100 kHz with an Ytterbium diode-pumped femtosecond amplifier. Individual mid-infrared spectra can thus be measured directly in the near infrared using a fast CMOS linescan camer...

Intrapulse Difference Frequency Generation (iDFG) is an interesting technique for generating femtosecond pulses in the Mid-Infrared (MIR) range with unique properties such as robust Carrier-Envelope Phase (CEP) stability. However, its efficiency is low compared to other techniques. In this paper, we describe an iDFG system operating within the 4–10...

Intrapulse Difference Frequency Generation (iDFG) is an interesting technique for generating femtosecond pulses in the Mid-Infrared (MIR) range with unique properties such as robust Carrier-Envelope Phase (CEP) stability. However, its efficiency is low compared to other techniques. In this paper, we describe an iDFG system operating within the 4 to...

We study a second harmonic generation interaction geometry in the case where both group velocity mismatch and walk-off have significant impacts. This results in a frequency-converted beam exhibiting a pulse front tilt. Using the global response function of the crystal, we provide an analytical model that allows to predict the spatiotemporal structu...

We characterize the intensity noise of two mid-infrared (MIR) ultrafast tunable (3.5-11 μm) sources based on difference frequency generation (DFG). While both sources are pumped by a high repetition rate Yb-doped amplifier delivering 200 μJ 300 fs at a central wavelength of 1030 nm, the first is based on intrapulse DFG (intraDFG), and the second on...

We demonstrate an ultrafast mid-infrared source architecture that implements both intrapulse difference frequency generation (iDFG) and further optical parametric amplification (OPA), in an all-inline configuration. The source is driven by a nonlinearly compressed high-energy Yb-doped-fiber amplifier delivering 7.4 fs pulses at a central wavelength...

We present a technique to optimize the intrapulse difference frequency generation efficiency for mid-infrared generation. The approach employs a multi-order wave plate that is designed to selectively rotate the polarization state of the incoming spectral components on the relevant orthogonal axes for subsequent nonlinear interaction. We demonstrate...

We report on an ultra-broadband mid-infrared source based on intrapulse difference-frequency-generation delivering 135 nJ, 50 fs-long pulses at 250 kHz repetition-rate. A bichromatic waveplate is used, enhancing the number of photons for the mid-infrared generation.

We report on an ultra-broadband mid-infrared source based on intrapulse difference-frequency-generation with time-delay and chirp optimizations of the pump and signal pulses, delivering 600 nJ, 50 fs pulses at 8.6 µm and 250 kHz repetition-rate.

We present a rapid-scanning approach to fluorescence-detected two-dimensional electronic spectroscopy that combines acousto-optic phasemodulation with digital lock-in detection. This approach shifts the signal detection window to suppress 1/f laser noise and enables interferometric tracking of the time delays to allow for correction of spectral pha...

We present a rapid-scanning approach to fluorescence-detected two-dimensional electronic spectroscopy that combines acousto-optic phase-modulation with digital lock-in detection. The approach shifts the signal detection window to suppress 1/f laser noise and enables interferometric tracking of the time delays to allow for correction of spectral pha...

Arbitrary-Detuning ASynchronous OPtical Sampling (ADASOPS) is a pump-probe technique which relies on the stability of femtosecond oscillators. It provides access to a multiscale time window ranging up to millisecond, combined with a sub-picosecond time resolution. In contrast with the first ADASOPS demonstration based on the interferometric detecti...

We demonstrate a rapid-scanning approach for fluorescence-detected two-dimensional electronic spectroscopy based on phase modulation and digital lock-in detection. The complex linear and non-linear signals of interest are retrieved simultaneously within several seconds of acquisition time.

We report on multidimensional spectroscopy in the mid-infrared, performed using a calomel-based acousto-optic programmable dispersive filter. Although the associated spectral resolution is currently not as good as what has been previously reported using time-domain interferometers or other pulse-shaping technologies, the extreme compactness of the...

Femtosecond amplifiers seeded by two independent femtosecond oscillators normally produce amplified pulse pairs with a timing jitter equal to the oscillator period, which is typically around 12 ns for Titanium:Sapphire lasers. Combining Arbitrary-Detuning Asynchronous Optical Sampling (AD-ASOPS) with an appropriate selection of amplified pulses, we...

We report on transient two-dimensional Fourier-Transform infrared spectroscopy (2DIR) after vibrational ladder climbing induced in the CO-moiety longitudinal stretch of carboxyhemoglobin. The population distribution, spreading up to seven vibrational levels, results in a non-equilibrium 2DIR spectrum evidencing a large number of peaks which can be...

We demonstrate that Arbitrary-Detuning ASynchronous OPtical Sampling (AD-ASOPS) makes possible multiscale pump-probe spectroscopy with time delays spanning from picosecond to millisecond. The implementation on pre-existing femtosecond amplifiers seeded by independent free-running oscillators is shown to be straightforward. The accuracy of the metho...

* Introduction * Time and Frequency * Dispersion of a Femtosecond Pulse * Basic Principle of a Femtosecond Laser * Nonlinear Optics and Kerr Effect * Mode-locking * Amplification * Generation of Attosecond Pulses

This letter presents a comparison between experimental and simulated two-dimensional mid-infrared spectra of carboxy-hemoglobin in the spectral region of the carbon monoxide stretching mode. The simulations rely on a fluctuating potential energy surface which includes both the effect of heme and the protein surroundings computed from molecular dyna...

We demonstrate that Arbitrary-Detuning ASynchronous OPtical Sampling (AD-ASOPS) makes possible multiscale pump-probe spectroscopy with time delays spanning from picosecond to millisecond. The implementation on pre-existing femtosecond amplifiers seeded by independent free-running oscillators is shown to be straightforward. The accuracy of the metho...

A method for time differentiation based on a Babinet-Soleil-Bravais compensator is introduced. The complex transfer function of the device is measured using polarization spectral interferometry. Time differentiation of both the pulse field and pulse envelope are demonstrated over a spectral width of about 100 THz with a measured overlap with the ob...

A recently reported variant of asynchronous optical sampling compatible with arbitrary unstabilized laser repetition rates is applied to pump-probe spectroscopy. This makes possible the use of a 5.1 MHz chirped pulse oscillator as the pump laser, thus extending the available time window to almost 200 ns with a time resolution as good as about 320 f...

A method of asynchronous optical sampling based on free-running lasers with no requirement on the repetition rates is presented. The method is based on the a posteriori determination of the delay between each pair of pulses. A resolution better than 400 fs over 13 ns total delay scan is demonstrated. In addition to the advantages of conventional as...

A device for managing light pulses for measuring the reaction of a sample exposed to a first light pulse, the measurement being performed by analysis of a signal emitted by the sample subjected to a second light pulse, shifted with respect to the first pulse by a determined interval of time, the device including two optical detectors for detecting...

We propose a new technique, using femtosecond Fourier-transform spectral interferometry, to measure the second-order nonlinear response of a material in two dimensions of frequency. We show numerically the specific and unique information obtained from such a two-dimensional measurement. The technique is demonstrated by measuring the second-order ph...

In heme-based sensor proteins, ligand binding to heme in a sensor domain induces conformational changes that eventually lead to changes in enzymatic activity of an associated catalytic domain. The bacterial oxygen sensor FixL is the best-studied example of these proteins and displays marked differences in dynamic behavior with respect to model glob...

We report a theoretical study that elaborates the influence of the polarization state of both the pump and the probe pulse in ultrafast coherent vibrational ladder climbing experiments in the mid-infrared. Whereas a subensemble in a randomly oriented sample of molecules is excited by the pump pulse in this multiphoton process, further inhomogeneiti...

Direct amplitude and phase shaping of mid-infrared femtosecond pulses is realized with a calomel-based acousto-optic programmable dispersive filter transparent between 0.4 and 20 μm . The shaped pulse electric field is fully characterized with high accuracy, using chirped-pulse upconversion and time-encoded arrangement spectral phase interferometry...

We demonstrate selective two-photon excited fluorescence microscopy with shaped pulses produced with a simple yet efficient scheme based on dispersive optical components. The pulse train from a broadband oscillator is split into two subtrains that are sent through different amounts of glass. Beam recombination results in pulse-shape switching at a...

We simultaneously observe ultrafast ligand dissociation and docking-site absorption in carboxy-heme proteins. Highly sensitive visible pump/infrared probe spectroscopy reveals multiply excited vibrational states exhibiting distinct differences for hemoglobin and FixL.

We investigate ultrafast vibrational ligand dynamics in carboxy hemoglobin using chirped pulse upconversion and demonstrate the formation of vibrationally multiply excited carbon monoxide trapped in the primary docking site of hemoglobin after photolysis. The bleach signal due to ligand dissociation and the incipient docking site absorption signal...

We report multiplexed two-photon imaging in vivo with fast pixel rates and micrometer resolution. Using coherent control of the two-photon excited fluorescence, we performed selective microscopy of GFP and endogenous fluorescence in developing Drosophila embryos.

We report on ultrafast visible pump/mid-infrared probe spectroscopy of the carboxy form of heme proteins by employing the recently developed chirped-pulse upconversion technique, which allows both high resolution and sensitivity over an extremely broad spectral range. Commonly, the bleach signal due to ligand dissociation and the incipient docking-...

1. Rappels d'optique linéaire 2. Modèle semi-classique de la réponse non-linéaire 3. Quelques phénomènes d'optique non-linéaires 4. Des lasers continus aux lasers femtosecondes 5. Caractérisation spatio-temporelle 6. Applications des impulsions femtosecondes

We apply a Fourier filtering technique for the global removal of coherent contributions, like perturbed free-induction decay, and noise, to experimental pump–probe spectra. A further filtering scheme gains access to spectra otherwise only recordable by scanning the probe’s center frequency with adjustable spectral resolution. These methods cleanse...

We observe that narrow spectral features in mid-infrared spectra obtained by chirped-pulse up-conversion are strongly distorted by cross-phase modulation between the mid-infrared field and the chirped pulse. We discuss the consequences of this effect on spectral resolution, and introduce a correction method that recovers masked lines. This simple c...

At the microscopic level, multidimensional response functions, such as the nonlinear optical susceptibility or the time-ordered response function, are commonly used tools in nonlinear optical spectroscopy for determining the nonlinear polarization resulting from an arbitrary excitation. In this Account, we point out that the approach successfully d...

We characterize mid-infrared pulses using upconversion to the visible regime by mixing with two collinear time-delayed replicas of an 800 nm chirped pulse. The phase is encoded as a function of the time-delay.

Coherent control can be used to selectively enhance or cancel concurrent multiphoton processes, and has been suggested as a means to achieve nonlinear microscopy of multiple signals. Here we report multiplexed two-photon imaging in vivo with fast pixel rates and micrometer resolution. We control broadband laser pulses with a shaping scheme combinin...

We track the path difference between interferometer arms with few-nanometer accuracy without adding optics to the beam path. We measure the interference of a helium-neon beam that copropagates through the interferometer with midinfrared pulses used for multidimensional spectroscopy. This can indicate motion, but not direction. By oscillating the pa...

We review different methods for characterizing mid-infrared femtosecond pulses, including linear methods such as electro-optic sampling, time- and frequency-domain interferometry, and nonlinear self-referenced methods such as frequency-resolved optical gating (FROG) and spectral phase interferometry for direct electric-field reconstruction (SPIDER)...

The nonclassicality of photon-added coherent fields in the thermal channel is investigated by exploring the volume of the negative part of the Wigner function which reduces with the dissipative time. The Wigner functions become positive when the decay time exceeds a threshold value. For the case of the single photon-added coherent state, we derive...

We have implemented the recently demonstrated technique of chirped-pulse upconversion of midinfrared femtosecond pulses into the visible in a visible pump-midinfrared probe experiment for high-resolution, high-sensitivity measurements over a broad spectral range. We have succeeded in time-resolving the CO ligand transfer process from the heme Fe to...

Prokhorenko et al. (Research Articles, 1 September 2006, p. 1257) reported that, in the weak-field regime, the efficiency of retinal isomerization in bacteriorhodopsin can be controlled by modulating the spectral phase of the photoexcitation pulse. However, in the linear excitation regime, the signal measured in an experiment involving a time-invar...

We demonstrate a programmable pulse characterization device based on an acousto-optic programmable dispersive filter. Both SH-FROG and SPIDER signals are obtained with a single optical setup. Experimental demonstration is provided on an amplified femtosecond system.

As was shown in previous chapters, the large peak intensities associated with femtosecond laser pulses make them well suited to nonlinear wave-mixing processes, allowing the generation of new colors. Such processes include second-harmonic generation, sum-frequency generation, parametric oscillation and amplification, and continuum generation. Howev...

Femtosecond spectroscopy aims at characterizing the dynamics of elementary excitations in material systems. One of the most common experimental techniques, spectrally resolved pump-probe spectroscopy, may in some cases present artifacts, the so-called coherent effects, which make data interpretation less straightforward than the incoherent picture...

Upon population of its excited state, the retinal chromophore in the membrane protein bacteriorhodopsin (bR) undergoes a sudden (less than approximately 10 fs) change in dipole moment, Deltamu, that can be visualized in a direct way by optical rectification of a broadband visible femtosecond light pulse to the infrared but has not been quantified i...

A two-dimensional (2D) infrared spectrum of Mn 2 ( C O ) 10 is measured by using chirped-pulse upconversion (CPU) of the nonlinear signal field plus a reference local oscillator. By converting the spectrum to the visible, a silicon CCD camera can be used. The method offers an attractive alternative to direct IR detection due to the technological ma...

Sum-frequency mixing between a chirped 800-nm pulse and an infrared pulse allows determination of the IR spectral phase and amplitude using spectral interferometry. A two-dimensional IR spectrum of a metal-carbonyl is also measured by upconversion.

We present an interferometric time-domain Fourier transform implementation of coherent anti-Stokes Raman scattering (CARS). Based on a single femtosecond laser source, the method provides a straight-forward scheme for obtaining high resolution CARS spectra. We give a theoretical description of the method, and demonstrate good agreement between simu...

We report a single-laser time-resolved Fourier transform implementation of coherent anti-Stokes Raman scattering microscopy that provides high resolution spectrally-resolved images. We also demonstrate coherent-control-based two-photon fluorescence microscopy for selective fluorescence excitation in live organisms.

We report a novel Fourier-transform-based implementation of coherent anti-Stokes Raman scattering (CARS) microscopy. The method employs a single femtosecond laser source and a Michelson interferometer to create two pulse replicas that are fed into a scanning multiphoton microscope. By varying the time delay between the pulses, we time-resolve the C...

Intense mid-infrared pulses tunable between 5 and 14 μ m with pulse energies of several microjoules were generated by difference-frequency mixing (DFM) in a GaSe crystal. Longer wavelengths (up to 18 μ m ) were achieved by DFM in a CdSe crystal. The infrared pulses were then characterized using various techniques: The spectrum was measured using a...

We demonstrate selective fluorescence excitation of specific molecular species in live organisms by using coherent control of two-photon excitation. We have acquired quasi-simultaneous images in live fluorescently-labeled Drosophila embryos by rapid switching between appropriate pulse shapes. Linear combinations of these images demonstrate that a h...

Multiphoton microscopy is an important tool that is increasingly used in biological research. The ease with which broadband femtosecond pulses can be created and manipulated has opened up new directions for enhancing multiphoton microscopy. In particular, pulse-shaping techniques can tailor broadband light to selectively excite fluorescent species....

Two-dimensional infrared (2DIR) spectroscopy provides direct access to ultrafast molecular dynamics by measuring time- and structure-dependent couplings between vibrational transitions. Biological molecules, such as proteins, have rich vibrational spectra that relate to key structural elements including secondary structure (alpha-helix, beta-sheet)...

We characterize ultrashort mid-infrared pulses through upconversion by using the stretched pulses obtained from the uncompressed output of a chirped-pulse amplifier. The power spectrum thus translated into the visible region can be readily measured with a standard silicon CCD camera-based spectrometer. The spectral phase is also characterized by a...

We report a novel Fourier transform method for measuring two-photon excitation spectra. We demonstrate this method using simple dye molecules and discuss its applications in two-photon fluorescence microscopy and optimal control. This method facilitates an intuitive interpretation of recent control experiments in terms of tuning the nonlinear spect...

Usual techniques for producing high-energy ultrashort pulses use the chirped pulse amplification (CPA) scheme, in which a combination of gratings and reflective optics to realize the stretching, amplification and compression stages are employed. This chapter presents a different approach based on the use of persistent spectral hole burning (PSHB) m...

We demonstrate vibrational climbing in the CO stretch of carboxyhemoglobin pumped by midinfrared chirped ultrashort pulses. By use of spectrally resolved pump-probe measurements, we directly observed the induced absorption lines caused by excited vibrational populations up to v = 6. In some cases, we also observed stimulated emission, providing dir...

We report femtosecond visible pump, midinfrared probe, spectrally integrated experiments resolving the dynamics of CO in myoglobin upon photodissociation. Our results show a progressive change in absorption strength of the CO vibrational transition during its transfer from the heme to the docking site, whereas the vibrational frequency change is fa...

The primary events in bacteriorhodopsin are investigated by coherent infrared emission spectroscopy of oriented purple membranes. Longlived vibrational motions involving charge displacements are observed following sudden (<11 fs) macroscopic membrane polarization appearing upon visible excitation.

We report spectrally-integrated, visible-pump, mid-infrared probe studies of the CO ligand in myoglobin. Supported by density functional calculations, we find that the CO oscillator strength and frequency changes occur on disparate timescales following dissociation.

We report a novel Fourier transform method of measuring two-photon excitation spectra. We demonstrate this method using a simple dye system and discuss its applications in two-photon fluorescence microscopy and quantum control.

The relative role of retinal isomerization and microscopic polarization in the phototransduction process of bacteriorhodopsin is still an open question. It is known that both processes occur on an ultrafast time scale. The retinal trans-->cis photoisomerization takes place on the time scale of a few hundred femtoseconds. On the other hand, it has b...

We performed pulse shaping and time reversal experiments using spectral holography based on persistent spectral hole burning in free-base naphthalocyanine-doped films. The application of a new pulse re-compression scheme based on a programmable hole burning material acting as a time reversal mirror is considered. In this work, we adapted the Fourie...

Mid-infrared ultrashort pulses of 9.2 - µ m center wavelength are characterized in both amplitude and phase. This is achieved by use of a variant of spectral phase interferometry for direct electric field reconstruction in which spectral interferometry has been replaced with time-domain interferometry, a technique that is well suited for infrared p...

We performed pulse-shaping and time-reversal experiments using spectral holography based on persistent spectral hole burning in free-base naphthalocyanine-doped films. We demonstrate that we can control the pulses diffracted from the hologram by shaping and then by characterizing these pulses in both amplitude and phase. A dephasing time of 29 ps (...

We performed pulse-shaping and time-reversal experiments using spectral holography based on persistent spectral hole burning in free-base naphthalocyanine-doped films. We demonstrate that we can control the pulses diffracted from the hologram by shaping and then by characterizing these pulses in both amplitude and phase. A dephasing time of 29 ps (...

We report on a new class of optical multidimensional Fourier-transform spectroscopy associated with a visible excitation infrared emission configuration, in which the emitted field results from second-order optical nonlinearities.

A Comment on the Letter by Tobias Guenther et al., Phys. Rev. Lett. 89, 057401 (2002). The authors of the Letter offer a Reply.

We introduce a new approach to the characterization of femtosecond optical pulses based on a remarkably simple setup combining a two-photon detector and a pulse shaper consisting of a longitudinal acousto-optic programmable filter. The operation of this setup is demonstrated through the use of a new version of spectral phase interferometry for dire...

We have developed a high energy (>2 μJ) source that produces ultrafast pulses tunable from 4 to 14 μm. Pulse spectrum and duration are characterised in real time using a Michelson interferometer.

We report on a new class of optical multidimensional Fourier-transform spectroscopy associated with a visible excitation infrared emission configuration, in which the emitted field results from second-order optical nonlinearities.

In a series of experiments we explore various aspects of femtosecond pulse shaping by coherent filters engraved in a persistent spectral hole burning (PSHB) material. We have in mind the coherent control of quantum systems, with high resolution and large number of addressable spectral points. We examine the phase correction efficiency of this appro...

We report on a new class of optical multidimensional Fourier-transform spectroscopy associated with a visible excitation–infrared emission configuration, in which the emitted field results from second-order optical nonlinearities. This configuration is demonstrated on a phase-matched sample of known nonlinear response by coherent measurement of the...

We have produced sub-picosecond pulses in the wavelength range 3-20 mum with energies as high as 2 muJ, through difference-frequency mixing in the crystal GaSe. Input beams for the non-linear mixing process came from either a regenerative amplifier operating in two-color mode, due to the spectral shaping of its injection beam, or an optical paramet...

La spectroscopie non-linéaire femtoseconde cohérente multidimensionnelle est une technique optique analogue à la résonance magnétique nucléaire multidimensionnelle. Elle repose sur l'utilisation d'impulsions femtosecondes et est démontrée ici dans le cas d'un processus de génération d'infrarouge par différence de fréquence dans une cristal non-liné...