Ultrafast extreme ultraviolet (XUV) transient absorption is the process by which atoms and
molecules absorb light on a timescale faster than the lifetime of the states involved …

The research topic of air lasing is of fundamental and practical importance, which has grown
rapidly in the past decade. Air lasing, or a laser‐like emission from air species including …

Air lasing from single ionized N 2+ molecules induced by laser filamentation in air has been
intensively investigated and the mechanisms responsible for lasing are currently highly …

In standard lasers, light amplification requires population inversion between an upper and a
lower state to break the reciprocity between absorption and stimulated emission. However …

We experimentally demonstrate the existence of long-lived coherent polarizations coupling
simultaneously ground state X (⁠ X 2 Σ g+⁠) to excited states A (⁠ A 2 Π u⁠) and B (⁠ B 2 Σ …

We show that the intensity of self-seeded N 2+ lasing at 391 nm, assigned to the B 2 Σ
u+(v′= 0)→ X 2 Σ g+(v′′= 0) emission, is enhanced by 2 orders of magnitude by …

Air lasing is a concept that refers to remote no-cavity (mirrorless) optical amplification in
ambient air with the air constituents as the gain media. Due to the high potential of air lasing …

Ultrafast ionization of atoms or molecules by intense laser pulses creates extremely non-
stationary ionic states. This process triggers attosecond correlated electron-hole dynamics …

Air lasing is a simple and promising technique to efficiently produce coherent light in the
atmosphere. Yet, its capability to obtain structured light like optical vortices or vector beams …

We investigate lasing of a N 2 gas induced by intense few-cycle near-IR laser pulses. By the
pump-probe measurements, we reveal that the intensity of the B Σ 2 u+− X Σ 2 g+ lasing …