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Controlling rotational air lasing lineshape by carrier-envelope offset phase.

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This study demonstrates carrier-envelope offset phase (CEP) control over nitrogen molecular ion (N 2 +) lasing spectra, altering lineshapes and revealing sub-optical-cycle dynamics.

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Area of Science:

  • Quantum Optics
  • Molecular Spectroscopy
  • Ultrafast Laser Physics

Background:

  • Carrier-envelope offset phase (CEP) controls attosecond electron dynamics.
  • Rotational lasing spectra typically emit over nanoseconds.
  • CEP control of rotational lasing spectra is not well-established.

Purpose of the Study:

  • To demonstrate CEP control of rotational lasing spectra in N 2 +.
  • To investigate the modulation of lasing lineshapes.
  • To explore sub-optical-cycle dynamics in air lasing.

Main Methods:

  • Utilizing few-cycle optical pulses with controlled CEP.
  • Analyzing rotational lasing spectra from B 2 Σ u + ( 0 ) to X 2 Σ g + ( 1 ) transitions.
  • Employing spectral analysis to observe lineshape transformations and peak coupling.

Main Results:

  • Achieved CEP control, transforming Lorentzian to Fano-type lasing lineshapes.
  • Observed interference between B-X coherence and self-phase modulation-induced supercontinuum.
  • Demonstrated stronger coupling between adjacent lasing peaks for lower rotational quantum numbers.

Conclusions:

  • CEP can effectively control rotational lasing lineshapes.
  • The findings provide insights into sub-optical-cycle dynamics.
  • This work establishes a framework for manipulating air lasing characteristics.