Terahertz beam array generated by focusing two-color-laser pulses into air with a microlens array

Terahertz (THz) radiation from a plasma filament array generated by focusing two-color laser pulses into the ambient air with a microlens array combining a lens is investigated. We observed a linear dependence of far-field collected THz radiation on the number of filaments and separated THz bunches that are less than 1 mm in diameter. These results indicate that the individual plasma filaments contribute incoherently to the entire THz output, which is demonstrated further with our simulation. Furthermore, the dependence of THz output on laser energy shows that the total energy of the THz beam array has not yet reached its saturation point under the conditions of current pump laser energy in our lab, indicating that it is still possible to further improve the THz output by further increasing the pump laser energy. This THz beam array may possibly be used in micro- or sub-millimeter multi-samples for THz imaging or as a stimuli array source for more scientific research in the future.