Spectral modulation of two coherently separated femtosecond laser pulses

Chin, See Leang; François, Véronique; Watson, Jennifer; Delisle, Claude

doi:10.1364/ao.31.003383

Cited by 43 publications

(23 citation statements)

References 7 publications

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“…The theory that follows is supported by the experiments of Chin et al (1992). With a grating spectrometer, they measured spectral modulation in the visible wavelength region caused by pairs of 150 femtosecond laser pulses separated by times varying between 5 × 10 −13 s and 3 × 10 −11 s. The pairs of pulses were periodically emitted at intervals of 1.3 × 10 −8 s. We use standard Fourier theory to predict the shapes of the features that pulses introduce in spectra.…”

Section: Spectral Modulations From Pulsating Objectsmentioning

confidence: 75%

“…The experiments of Chin et al (1992) illustrate the sinusoidal modulation of S (ω) predicted for 2 pulses by Eq. (4) with N = 2 as…”

Section: Spectral Modulations From Pulsating Objectsmentioning

confidence: 85%

“…Although the basic theory on which this article is based is validated by the experiments of Chin et al (1992), one may argue that the pairs of pulses in Chin et al (1992) are coherent, since the division was performed by a Michelson interferometer, while the pulses in an astronomical source may not be coherent. One may then proceed to argue that while coherent light beams interfere, it is "well-known" that incoherent ones do not.…”

Section: Discussion Of the Applicability Of The Spectral Modulation Tmentioning

confidence: 99%

“…The experiments of Chin et al (1992) show that there is no violation of basic physical principles. However, a potential problem is that short timescales are indicative of small volumes and consequently high energy densities for distant objects that thermal sources and well-understood physics may have problems explaining.…”

Section: Energy Density Considerationsmentioning

confidence: 99%

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Spectral signatures of ultra-rapidly varying objects in spectroscopic surveys

Borra¹

2010

A&A

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Context. Astronomy is an observationally-led subject where chance discoveries play an important role. The time domain is the least explored in astronomy. Aims. We alert spectroscopists, particularly those involved in surveys, that rapidly varying sources can induce periodic patterns in spectra. Methods. The analytical treatment is based on standard Fourier theory. It is used to predict the shapes of features introduced by intensity pulses in spectra. These are the shapes that one must look for in spectral surveys. The theoretical analysis is supported by published experiments that measured the spectral modulation, in the visible wavelength region, caused by pairs of 150 femtosecond laser pulses separated by time periods varying between 5 × 10 −13 s and 3 × 10 −11 s. Results. Detection of spectral signatures would allow the detection of new classes of objects that emit bursts of pulses separated by time intervals that are too short to be detected with conventional techniques. The principal advantage of the technique is that there is no need for specialized instruments or surveys: one must only incorporate algorithms capable of searching for periodic spectroscopic signals, such as those shown in a figure in this article, into existing data analyzis software and use it with standard spectroscopic surveys (including existing ones).

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Section: Spectral Modulations From Pulsating Objectsmentioning

confidence: 75%

“…The experiments of Chin et al (1992) illustrate the sinusoidal modulation of S (ω) predicted for 2 pulses by Eq. (4) with N = 2 as…”

Section: Spectral Modulations From Pulsating Objectsmentioning

confidence: 85%

Section: Discussion Of the Applicability Of The Spectral Modulation Tmentioning

confidence: 99%

Section: Energy Density Considerationsmentioning

confidence: 99%

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Spectral signatures of ultra-rapidly varying objects in spectroscopic surveys

Borra¹

2010

A&A

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“…Each spectral peak in the modulated terahertz spectrum represents a constructive interference of this spectral component. The intensity at each frequency is a coherent superposition of the spectral components from the reference and control terahertz pulses at this measured wavelength (  ) [11], i.e.,…”

mentioning

confidence: 99%

Spectral interference of terahertz pulses from two laser filaments in air

Chen

Zhang

Yuan

et al. 2015

Applied Physics Letters

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Spectral interference is experimentally demonstrated by two terahertz pulses emitting from filaments induced by two successive femtosecond laser pulses in air. Here a leading pulse is set to be weaker than a trailing pulse and their temporal separation is larger than the pulse duration of the terahertz pulses. When the leading pulse is stronger than the trailing pulse, the frequency modulation within the whole terahertz envelope is greatly deteriorated due to nonlinear effects applying on the trailing pulse through the plasmas generated by the leading pulses. Such unique terahertz spectrum may find applications in terahertz spectroscopy.

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Peculiar Emission Line Generation from Ultra-Rapid Quasi-Periodic Oscillations of Exotic Astronomical Objects

Borra

2017

J Astrophys Astron

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The purpose of this article is to alert Astronomers, particularly those using spectroscopic surveys, to the fact that exotic astronomical objects (e.g. quasars or active galactic nuclei) that send ultra-rapid quasi periodic pulses of optical light would generate spectroscopic features that look like emission lines. This gives a simple technique to find quasi periodic pulses separated by times smaller than a nanosecond. One should look for emission lines that cannot be identified with known spectral lines in spectra. Such signals, generated by slower pulses, could also be found in the far infra-red, millimeter and radio regions, where they could be detected as objects unusually bright in a single narrow-band filter or channel. The outstanding interest of the technique comes from its simplicity so that it can be used to find ultra-rapid quasi-periodic oscillators in large astronomical surveys. A very small fraction of objects presently identified as Lyman  emitters that do not have other spectral features to confirm the Lyman  redshift, may possibly be quasi-periodic oscillators. However this is only a hypothesis that needs more observations for confirmation.3

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Spectral modulation of two coherently separated femtosecond laser pulses

Abstract: A train of 150-fs 76-MHz pulses is directed into a Michelson interferometer with a path difference larger than the pulse spatial length. A modulated spectrum with a modulation frequency that increases with the path difference is observed. The consequence is discussed.

Cited by 43 publications

References 7 publications

Spectral signatures of ultra-rapidly varying objects in spectroscopic surveys

Spectral signatures of ultra-rapidly varying objects in spectroscopic surveys

Spectral interference of terahertz pulses from two laser filaments in air

Peculiar Emission Line Generation from Ultra-Rapid Quasi-Periodic Oscillations of Exotic Astronomical Objects

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