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Related papers: Femtosecond Covariance Spectroscopy

200 papers

Nonlinear optical processes are used in biological microscopy to surpass the diffraction limit on resolution, image deeper into brain tissues, and identify biomolecules without exogenous labels. These techniques typically require high…

Stochastically driven nonlinear processes limit the number of amplified modes in a natural system due to competitive mode interaction, which is accompanied by loss of coherence when increasing the complexity of system. Specifically, we find…

Optics · Physics 2016-07-21 Lei Gao , Tao Zhu , Stefan Wabnitz , Min Liu , Wei Huang

Noise can play an important role in nonlinear pulse propagation. It is not only the origin of fluctuations in supercontinuum but can also determine the generated signal amplitude and phase, as seen in phenomena such as noise-seeded…

Optics · Physics 2025-07-08 Yi-Hao Chen , Frank Wise

The axial dependence of femtosecond filamentation in air is measured under conditions of varying laser pulsewidth, energy, and focusing f-number. Filaments are characterized by the ultrafast z-dependent absorption of energy from the laser…

A possibility to greatly enhance frequency-conversion efficiency of stimulated Raman scattering is shown by making use of extraordinary properties of three-wave mixing of ordinary and backward waves. Such processes are commonly attributed…

Specific features of nonlinear interference processes at quantum transitions in near- and fully-resonant optically-dense Doppler-broadened medium are studied. The feasibility of overcoming of the fundamental limitation on a…

Quantum Physics · Physics 2009-11-11 A. K. Popov , S. A. Myslivets , Thomas F. George

Raman backscattered radiation of intense laser pulses in plasma is investigated for a wide range of intensities relevant to laser wakefield acceleration. The weakly nonlinear dispersion relation for Raman backscattering predicts an…

Plasma Physics · Physics 2016-12-21 D. Kaganovich , B. Hafizi , J. P. Palastro , A. Ting , M. H. Helle , Y. -H. Chen , T. G. Jones , D. F. Gordon

We present an effective linear response approach to pump-probe femtosecond coherence spectroscopy in the well separated pulse limit. The treatment presented here is based on a displaced and squeezed state representation for the…

Chemical Physics · Physics 2009-11-06 Anand T. N. Kumar , Florin Rosca , Allan Widom , Paul M. Champion

We propose a new technique for comparing two Raman active samples. The method employs optical interference of the signals generated via coherent anti-Stokes Raman scattering (CARS) of broadband laser pulses with noisy spectra. It does not…

Quantum Physics · Physics 2015-05-27 Evgeny A. Shapiro , Stanislav O. Konorov , Valery Milner

Noise spectroscopy elucidates the fundamental noise sources in spin systems, thereby serving as an essential tool toward developing spin qubits with long coherence times for quantum information processing, communication, and sensing. But…

It is by now established that, remarkably, the addition of noise to a nonlinear system may sometimes facilitate, rather than hamper the detection of weak signals. This phenomenon, usually referred to as stochastic resonance, was originally…

Condensed Matter · Physics 2009-10-31 Redouane Fakir

We propose a novel femtosecond stimulated Raman spectroscopy (FSRS) technique that combines entangled photons with interference detection to select matter pathways and enhance the resolution. Following photo excitation by an actinic pump,…

Quantum Physics · Physics 2014-07-15 Konstantin E. Dorfman , Frank Schlawin , Shaul Mukamel

We study an intense-short pulse propagation in a saturable cubic-quintic nonlinear media in the presence of nonlinear dispersion within the framework of an extended variational approach. We derive an effective equation for the pulse width…

Atomic Physics · Physics 2021-10-14 Sudipta Das , Kajal Krishna Dey , Golam Ali Sekh

Four-wave mixing processes are ubiquitous in ultrafast optics and the determination of the coefficients of the $\chi^{(3)}$ tensor is thus essential. We introduce a novel time-resolved ultrafast spectroscopic method to characterize the…

In practice, observations are often contaminated by noise, making the resulting sample covariance matrix to be an information-plus-noise-type covariance matrix. Aiming to make inferences about the spectra of the underlying true covariance…

Statistics Theory · Mathematics 2015-08-25 Ningning Xia , Xinghua Zheng

We investigate nonlinear Kerr-induced coherence effect on a superluminal probing light pulse in a gain-assisted N-type 4-level atomic system via an intense monochromatic laser field. The dispersion exhibits a novel, interesting and useful…

Optics · Physics 2013-11-28 Bakht Amin Bacha , Fazal Ghafoor

Three-color coherent anti-Stokes Raman scattering represents non-degenerate four wave mixing process that includes both a non-resonant and resonant processes, the contributions of which depend on how the molecular vibrational modes are…

Optics · Physics 2020-10-14 Supriya Nagpal , Bryan Semon , Gombojav O. Ariunbold

The use of averaging has long been known to reduce noise in statistically independent systems that exhibit similar levels of stochastic fluctuation. This concept of averaging is general and applies to a wide variety of physical and man-made…

We study coherent backscattering of a quasi-monochromatic laser by a dilute gas of cold two-level atoms. We consider the perturbative regime of weak intensities, where nonlinear effects arise from {\em inelastic} two-photon scattering…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 T. Wellens , B. Gremaud , D. Delande , C. Miniatura

Nonlinear optical methods are becoming ubiquitous in many areas of modern photonics. They are, however, often limited to a certain range of input parameters, such as pulse energy and average power, since restrictions arise from, for…