Coherent Raman spectroscopy with frequency-shifted and shaped pulses from a photonic-crystal fiber

Voronin

Федотов

et al. 2018

J Raman Spectroscopy

Self Cite

Coherent anti‐Stokes Raman scattering is shown to provide a versatile spectroscopic protocol for the optical interrogation of broadband quantum memories based on long‐lived coherent phonons in solids. In our scheme of coherent anti‐Stokes Raman scattering‐interrogated broadband quantum memory, a frequency‐tunable Stokes field, delivered by dispersion‐ and nonlinearity‐engineered photonic‐crystal fiber, maps the broadband pump wave packet into a memory based on coherently driven optical phonons of diamonds. The probe field is then applied with a variable delay time to read out the coherence driven by the pump and Stokes fields, giving rise to an anti‐Stokes signal, which serves to report the state of the phonon memory.

Section: Resultsmentioning

confidence: 92%

Coherent Raman spectroscopy of solid‐state broadband quantum memories

Voronin

Федотов

et al. 2018

J Raman Spectroscopy

Self Cite

“…For a more compact design, the key components of the developed laser platform can be implemented in the fiber format. The utility of individual specialty‐fiber sources and frequency converters of ultrashort pulses for chirped‐pulse nonlinear Raman microspectroscopy has been already demonstrated …”

Section: Resultsmentioning

confidence: 99%

A compact laser platform for nonlinear Raman microspectroscopy: multimodality through broad chirp tunability

Stepanov

Tikhonov

et al. 2016

J Raman Spectroscopy

We demonstrate a compact laser platform that integrates stimulated and coherent Raman microscopy with high-resolution nonlinear Raman spectroscopy. Ultrashort laser pulses with a carefully managed, broadly tunable chirp are shown to enable a comfortable switching between the high-contrast microscopy and high-resolution spectroscopy modalities in both stimulated and coherent versions of nonlinear Raman scattering. Sub-10-cm À1 spectral resolution in stimulated Raman spectroscopy is demonstrated through a careful compensation of nonlinear phase distortions of ultrashort laser pulses. This offers a powerful tool for a reliable identification of molecular vibrations with close frequencies, enhancing the chemical selectivity of spectroscopic analysis of complex multicomponent systems. Introduction and Wolfgang Kiefer's legacyHigh-resolution spectroscopic analysis and ultrafast, short-pulse interrogation are the two main modalities of optical technologies based on nonlinear Raman scattering. [1,2] While high-resolution Raman spectroscopy [3,4] requires narrowband probes, capable of resolving individual molecular or atomic features in often crowded Raman spectra of complex chemical systems, broadband, shortpulse drivers offer a vast arsenal of tools [5,6] for time-resolved studies of ultrafast dynamics in physical, chemical, and biological systems [1,2,7] and open a whole new world of chemically specific, high-speed nonlinear microscopy. [8][9][10] The requirements on laser fields needed to implement these modalities are seemingly incompatible.Wolfgang Kiefer, one of the pioneers of the field of Raman spectroscopy, whose work had a profound impact on the field and who prominently contributed to the development of high-spectralresolution Raman methods, [11,12] was also among the first visionary scientists who recognized the tremendous potential of emerging short-pulse laser sources for Raman technologies. [13][14][15] This vision has in many ways shaped the future of the field. Within the past two decades, nonlinear Raman processes driven by ultrashort pulses have played a central role in ultrafast science, providing methods that help to probe [16,17] and control [18][19][20][21] ultrafast processes on the picosecond, femtosecond, and attosecond time scale, [22] as well as open new horizons in standoff detection [23,24] and ultrashort waveform synthesis. [25,26] With a powerful impetus gained from the invention of nonlinear Raman microscopy, [8,27] short-pulse Raman techniques find growing applications in bioimaging, enabling a chemically selective, high-frame-rate detection of intracellular dynamics, [28] diagnostics of lipid membranes, [29] and neurophysiological studies. [30][31][32][33][34] Ultrashort laser pulses inevitably impose limitations on the spectral resolution in nonlinear-optical microspectroscopy, making it difficult to resolve closely lying and overlapping lines in Raman spectra and to extract the informative signal in the microscopy of multicomponent biological systems. However, the coherence of laser p...

“…In CARS microspectroscopy and imaging, this nonresonant background has long been viewed as a fundamental limitation on the sensitivity of coherent Raman techniques, strongly motivating the search for effective means for its suppression through carefully optimized polarization arrangements24, schemes with time-delayed probe pulses14, and pulse-shaping approaches5. On the other hand, nonresonant coherent Raman scattering is known to provide a constant-phase component of the overall coherent Raman signal, which helps retrieve the phases of Raman-active modes3421 and resolve overlapping Raman responses from complex molecules2223, offering elegant solutions for phase-contrast microscopy24 and multimodal Raman imaging252627.…”

Section: Resultsmentioning

confidence: 99%

“…Our experimental approach employs an optical driver consisting of a pair of chirped pulses, which has been used earlier for coherent Raman spectroscopy171819262728, to demonstrate a smooth phase tunability of coherent Raman scattering. Unlike the earlier work where pulse shaping was used to efficiently suppress the nonresonant background in CARS, in our scheme, the nondispersive coherent background resulting from nonresonant FWM is used to visualize the tunable phase of the coherent Raman response from molecular vibrations driven by a pair of chirped laser pulses.…”

Section: Resultsmentioning

confidence: 99%

The phase-controlled Raman effect

Федотов

et al. 2013

Sci Rep

Unlike spontaneous Raman effect, nonlinear Raman scattering generates fields with a well-defined phase, allowing Raman signals from individual scatterers to add up into a highly directional, high-brightness coherent beam. Here, we show that the phase of coherent Raman scattering can be accurately controlled and finely tuned by using spectrally and temporally tailored optical driver fields. In our experiments, performed with spectrally optimized phase-tunable laser pulses, such a phase control is visualized through the interference of the coherent Raman signal with the field resulting from nonresonant four-wave mixing. This interference gives rise to Fano-type profiles in the overall nonlinear response measured as a function of the delay time between the laser pulses, featuring a well-resolved destructive-interference dip on the dark side of the Raman peak. This phase-control strategy is shown to radically enhance the coherent response from weak Raman modes, thus helping confront long-standing challenges in nonlinear Raman imaging and microspectroscopy.