Dmitry Pestov - Academia.edu (original) (raw)

Papers by Dmitry Pestov

APS Texas Sections Spring Meeting Abstracts, Mar 1, 2005

Quantum coherence dynamics on vibrational transitions in organic molecules is studied by means of... more Quantum coherence dynamics on vibrational transitions in organic molecules is studied by means of femtosecond Coherent Anti-Stokes Raman Scattering (CARS) technique. CARS signal profiles for high-frequency Raman transitions in methanol and ethanol, as representative simple ...

Conference on Lasers and Electro-Optics, May 6, 2007

Page 1. Real-Time Detection of Bacterial Spores Arthur Dogariu1, Yu Huang1, Alexander Goltsov1, D... more Page 1. Real-Time Detection of Bacterial Spores Arthur Dogariu1, Yu Huang1, Alexander Goltsov1, Dmitry Pestov2, Robert K. Murawski2, Alexei V. Sokolov2, Marlan O. Scully1,2 1Princeton University, Princeton, NJ 2Texas A&M University, College Station, TX ...

CRC Press eBooks, Jun 5, 2009

Ultrashort shaped pulses are becoming available and their use for biomedical imaging will permit ... more Ultrashort shaped pulses are becoming available and their use for biomedical imaging will permit signal enhancements, allow selective excitation, and reduced photobleaching. These pulses are also enabling new imaging modalities which provide greater chemical information.

ABSTRACT We introduce a temperature measurement method using single beam CARS spectroscopy to cre... more ABSTRACT We introduce a temperature measurement method using single beam CARS spectroscopy to create a time profile in the spectral domain. Analysis of signal decay provides temperature of multiple chemical species in a single laser shot.

Applied Physics Letters, Aug 17, 2009

The feasibility is explored by single-beam coherent anti-Stokes Raman scattering ͑CARS͒ spectrosc... more The feasibility is explored by single-beam coherent anti-Stokes Raman scattering ͑CARS͒ spectroscopy of gas-phase diatomic molecules related to combusting flows, with implications for gas-phase thermometry. We demonstrate CARS of gas-phase N 2 using a shaped ϳ7 fs laser pulse, investigate the dependence of the CARS signal on the total pressure of the probed environment, both in pure N 2 and in mixtures with Ar, discuss the observed signal-to-noise ratio, and suggest improvements to be considered for reliable single-shot measurements at flame temperatures.

Proceedings of SPIE, Feb 11, 2010

We formulate a simple strategy for mitigation of laser-induced damage through pulse shaping and d... more We formulate a simple strategy for mitigation of laser-induced damage through pulse shaping and demonstrate experimentally the effect of laser pulse duration on the degree of optically induced damage for two-photon microscopy imaging. We use a broadband Ti:Sapphire laser source, aided with a shaper, and adjust both the laser pulse duration and energy to maintain constant two-photon excitation efficiency. The damage is assessed by the dynamics of two-photon excited autofluorescence intensity and sample morphology during prolonged laser exposure. We observe that for a 5-mum layer of skin tissue the damage rate is independent of the pulse shape, which suggests that the primary damage (bleaching) mechanism stems from the two-photon excitation itself. For optically thick dried blood samples, taken as another example, the data suggests that the damage is driven by one-photon absorption. In the later case, it is favorable to use shorter laser pulses to mitigate photodamage while maintaining adequate intensity of two-photon excited autofluorescence.

Proceedings of SPIE, Feb 12, 2009

ABSTRACT High-order dispersion of ultrashort laser pulses (with ~100 nm bandwidth) is shown to ac... more ABSTRACT High-order dispersion of ultrashort laser pulses (with ~100 nm bandwidth) is shown to account for significant reduction of two-photon excitation fluorescence and second harmonic generation signal produced at the focal plane of a laser-scanning two-photon microscope. The second- and third-order corrections recover 20-40% of the signal intensity expected for a transform-limited laser pulse, while the rest depends on the proper compensation of higher-order terms. It can be accomplished through the use of a pulse shaper by measuring and correcting all nonlinear spectral phase distortions.

Proceedings of SPIE, Feb 10, 2011

We demonstrate a modular and versatile experimental setup that enables straightforward compressio... more We demonstrate a modular and versatile experimental setup that enables straightforward compression (and then shaping) of ultrashort laser pulses at the imaging plane of a two-photon microscope. A commercially available pulse shaper is used in conjunction with a commercially available broadband Ti:Sapphire oscillator to produce sub-8fs pulses at the focus of a high-numerical-aperture objective. Automated adaptive pulse compression, based on

Journal of The Optical Society of America B-optical Physics, Apr 17, 2007

We study near-resonant femtosecond coherent anti-Stokes Raman scattering (CARS) of dipicolinic ac... more We study near-resonant femtosecond coherent anti-Stokes Raman scattering (CARS) of dipicolinic acid (DPA) by exciting the molecular system with a pair of visible pump and Stokes pulses and probing the resultant molecular coherence with a time-delayed UV probe pulse. We record the generated Stokes and anti-Stokes pulse energies as functions of DPA concentration. We observe that the CARS signal has a maximum and the powerlaw dependence is steeper than the well-known quadratic one. We present a model that describes the propagation of the generated signal through the medium. From this model, we derive an analytical expression that closely agrees with our experimental data. Since DPA serves as a marker molecule for bacterial spores, our results help to establish the detectability limits for a lethal spore dosage when the present technique is applied.

Journal of Raman Spectroscopy, Jul 1, 2009

We demonstrate a femtosecond‐oscillator‐based system for coherent anti‐Stokes/Stokes Raman scatte... more We demonstrate a femtosecond‐oscillator‐based system for coherent anti‐Stokes/Stokes Raman scattering microscopy, wherein impulsive Raman excitation is combined with narrowband, time‐delayed, and therefore, background‐free probing. We show that this simple technique can be used for microscopic imaging with chemical contrast. Copyright © 2009 John Wiley & Sons, Ltd.

Journal of Physical Chemistry A, Jul 25, 2012

ABSTRACT Broadband Ti:Sapphire oscillator output, guided through a pulse shaper, is compressed do... more ABSTRACT Broadband Ti:Sapphire oscillator output, guided through a pulse shaper, is compressed down to sub-8fs at the focus of a high-NA microscope objective. The compression is verified in situ by interferometric autocorrelation, and images were obtained.

Journal of Raman Spectroscopy, Jan 18, 2010

Coherent anti-Stokes Raman scattering (CARS) spectroscopy of gas-phase CO 2 is demonstrated using... more Coherent anti-Stokes Raman scattering (CARS) spectroscopy of gas-phase CO 2 is demonstrated using a single femtosecond (fs) laser beam. A shaped ultrashort laser pulse with a transform-limited temporal width of ∼7 fs and spectral bandwidth of ∼225 nm (∼3500 cm −1) is employed for simultaneous excitation of the CO 2 Fermi dyads at ∼1285 and ∼1388 cm −1. CARS signal intensities for the two Raman transitions and their ratio as a function of pressure are presented. The signal-to-noise ratio of the single beam-generated CO 2 CARS signal is sufficient to perform concentration measurements at a rate of 1 kHz. The implications of these experiments for measuring CO 2 concentrations and rapid pressure fluctuations in hypersonic and detonation-based chemically reacting flows are also discussed.

Journal of Biomedical Optics, 2009

An adaptive pulse shaper controlled by multiphoton intrapulse interference phase scanning was use... more An adaptive pulse shaper controlled by multiphoton intrapulse interference phase scanning was used with a prism-pair compressor to measure and cancel high-order phase distortions introduced by a high-numerical-aperture objective and other dispersive elements of a two-photon laser-scanning microscope. The delivery of broad-bandwidth ͑ϳ100 nm͒, sub-12-fs pulses was confirmed by interferometric autocorrelation measurements at the focal plane. A comparison of two-photon imaging with transform-limited and secondorder-dispersion compensated laser pulses of the same energy showed a 6-to-11-fold improvement in the two-photon excitation fluorescence signal when applied to cells and tissue, and up to a 19-fold improvement in the second harmonic generation signal from a rat tendon specimen.

We demonstrate a single-beam coherent anti-Stokes Raman scattering (CARS) technique for gas-phase... more We demonstrate a single-beam coherent anti-Stokes Raman scattering (CARS) technique for gas-phase thermometry that assesses the species-specific local gas temperature by single-shot time-to-frequency mapping of Raman-coherence dephasing. The proof-of-principle experiments are performed with air in a temperature-controlled gas cell. Impulsive excitation of molecular vibrations by an ultrashort pump/Stokes pulse is followed by multi-pulse probing of the 2330-cm-1 Raman transition of N 2. This sequence of colored probe pulses, delayed in time with respect to each other and corresponding to three isolated spectral bands, imprints the coherence dephasing onto the measured CARS spectrum. For calibration purposes, the dephasing rates are recorded at various gas temperatures, and the relation is fitted to a linear regression. The calibration data are then used to determine the gas temperature and are shown to provide better than 15 K accuracy. The described approach is insensitive to pulse energy fluctuations and can, in principle, gauge the temperature of multiple chemical species in a single laser

Bulletin of the American Physical Society, Feb 28, 2012

Bulletin of the American Physical Society, 2015