Air lasing from singly ionized N2 driven by bicircular two-color fields

We experimentally investigate air lasing emission from singly ionized nitrogen molecules exposed to bicircular two-color (BTC) femtosecond laser pulses. The light driven electron recollision is suppressed in the corotating BTC field as compared to the counter-rotating one. It allows us to straightforwardly examine the role of electron recollision on the air lasing generation by simply changing the rotating sense of the BTC fields. Lasing emission is observed for both corotating and counter-rotating BTC fields without noticeable difference when the rotating sense is switched from one to the other case. It indicates a minor contribution of electron recollision on the air lasing emission. In addition to the well-observed linear polarization, we demonstrate that the polarization of the newborn lasing emission can be remotely manipulated from linear to circular by controlling the polarization of the driving second-harmonic field which at the same time acts as the seed.