Generation of fractional and multiple imaginary rotational alignment echoes

Lian, Zhao; Hu, Zhixiong; Qi, Hongxia; Fei, Dehou; Luo, Sizuo; Zhou, Chen; Shu, Chuan-Cun

doi:10.1103/physreva.104.053105

Cited by 11 publications

(2 citation statements)

References 46 publications

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“…[23,24] The adjustability features of the echo were also exploited to significantly improve the alignment of the acetone molecule at room temperature, enabling the third-harmonic generation from circularly polarized light otherwise not detectable through alignment revivals of this molecule. [25] Other applications of rotational echoes can be found, for instance, compensation of the centrifugal distortion of CH 3 I molecule, [14] calibration of the degree of laser-induced molecular alignment, [26] unidirectional rotation of molecular rotors, [27] and high-order harmonic generation. [28] In echo spectroscopy, it is usual to perform measurements for different time occurrences of the echoes.…”

Section: Introductionmentioning

confidence: 99%

Feedback Optimization Strategy for Rotational Alignment Echo Spectroscopy

Bournazel,

Espaignol,

Béjot

et al. 2023

Advanced Photonics Research

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The recent discovery of rotational echoes has contributed to extend the applications of field‐free molecular alignment to short time scales, namely to a temporal region preceding the first alignment revival of the molecule. Most echo measurements require adjusting the position of the echo over time, which in the case of molecular alignment echo unavoidably leads to a change in its amplitude, unless the intensity of the pulse sequence triggering the echo is properly modified. Herein, it is proposed to avoid this drawback by using an optical pulse shaper steered by a learning algorithm. It is demonstrated that a temporal shaping, whose characteristics are optimized to maintain a constant echo amplitude regardless of its creation time, can be generated by controlling the spectral phase and amplitude of the laser pulse which are then used in an open‐loop control system. As a proof of principle, the optimization strategy is applied to the observation of short‐term dissipative dynamics of laser‐aligned molecules exposed to collisions and to the measurement of associated decoherence and population decay time constants.

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Section: Introductionmentioning

confidence: 99%

Feedback Optimization Strategy for Rotational Alignment Echo Spectroscopy

Bournazel,

Espaignol,

Béjot

et al. 2023

Advanced Photonics Research

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show abstract

“…In some cases, further echoes can be observed at Δt = 2τ 12 , 3τ 12 , etc. In addition to these types of echoes (often called full echoes) that appear at time delay Δt = Nτ 12 , where N is a positive integer, echoes can also be formed at the rational fractions of time delay and are called fractional alignment echoes [25][26][27]. For example, echoes occurring at time Δt = τ 12 /2 and Δt = τ 12 /3 are referred to as 1/2 echoes and 1/3 echoes, respectively.…”

Section: Introductionmentioning

confidence: 99%

Creating alignment echoes using a phase-shaped femtosecond laser pulse

Xu¹,

Liu²,

Huang³

2022

J. Phys. B: At. Mol. Opt. Phys.

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In recent years, molecular alignment echo induced by a pair of time-delayed femtosecond laser pulses has been proposed and aroused wide research interest. We demonstrate that, however, the alignment echo can be alternatively produced by a shaped femtosecond laser pulse with the V-style spectral phase modulation. The full, fractional and imaginary alignment echoes are formed by the excitation of the tailored two time-delayed sub-pulses. Both the delay time and the ratio of the intensity between two sub-pulses can be easily manipulated by designing the modulation parameters to induce various types of the echoes. We further show that the optimal ratio of the intensity between two sub-pulses that results in the maximal alignment degrees of the full echo closely correlates with the energy of the sub-pulse. When the pulse energy is relatively low, the maximal alignment degree of the full echo is obtained as the two sub-pulses with equal intensity. The optimal ratio of the intensity increases with the excitation energy of the first pump pulse.

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Investigation on gaseous molecular alignment echoes induced by the intense phase-tunable terahertz pulses

2024

Indian J Phys

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Generation of fractional and multiple imaginary rotational alignment echoes

Cited by 11 publications

References 46 publications

Feedback Optimization Strategy for Rotational Alignment Echo Spectroscopy

Feedback Optimization Strategy for Rotational Alignment Echo Spectroscopy

Creating alignment echoes using a phase-shaped femtosecond laser pulse

Investigation on gaseous molecular alignment echoes induced by the intense phase-tunable terahertz pulses

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