Unipolar and Subcycle Extremely Short Pulses: Recent Results and Prospects (Brief Review)

Tailoring the waveshape of optical unipolar pulses in a multi-level resonant medium

“…The respective simulation results are depicted in Fig. 16. Here one see besides the unipolar bursts also rectangularshaped unipolar pulses placed right next to the stronger half-sine peaks.…”

“…The pulses with the non-zero values of the electric pulse area S E ( r) are called unipolar ones. The most prominent property of unipolar pulses is the transfer of mechanical momentum to charged particles and thus their strong acceleration [14,16]. This property naturally play a key role when driving free charges, but can be also expected to strongly influence the interaction of unipolar pulses with bound charges in resonant media.…”

“…However, when the driving pulse duration is reduced to be less than the periods of the resonant transitions in the medium the key features of the light-matter interaction get completely altered [14,16]. In particular, the efficiency of the medium excitation in this case is primarily determined by the value of the electric pulse area Eq.…”

Nonharmonic Spatial Population Difference Structures Created by Unipolar Rectangular Pulses in a Resonant Medium

“…Such short relaxation times and dipole moments of tens of Debye are characteristic of various nanostructures [44][45][46], and unipolar pulses seem promising for ultrafast population control in quantum dots, nanoparticles etc. [23]. Note that the interaction of atto-second pulses with nanostructures has been the subject of active study lately [47][48][49].…”

“…Unlike conventional pulses with a harmonic shape, UPs can have a non-zero electric area S E (r, t) = E(r, t)dt (E(r, t) is electric field strength, t is time). Interest in UPs is associated with the possibility of their unidirectional action on charges, and as a result, the ability to quickly and efficiently control the properties of atoms [21], molecules [22] and nanostructures [23].…”