Spatial Patterns of Dissipative Polariton Solitons in Semiconductor Microcavities

Abstract

We report propagating bound microcavity polariton soliton arrays consisting of multipeak structures either along (x) or perpendicular (y) to the direction of propagation. Soliton arrays of up to five solitons are observed, with the number of solitons controlled by the size and power of the triggering laser pulse. The breakup along the x direction occurs when the effective area of the trigger pulse exceeds the characteristic soliton size determined by polariton-polariton interactions. Narrowing of soliton emission in energymomentum space indicates phase locking between adjacent solitons, consistent with numerical modeling which predicts stable multihump soliton solutions. In the y direction, the breakup originates from inhomogeneity across the wave front in the transverse direction which develops into a stable array only in the solitonic regime via phase-dependent interactions of propagating fronts. [6,7]. In many aspects, solitons behave like artificial particles. They may repel or attract depending on their relative phase as was shown in optical fibers [8] and cold atom systems [9]. Multisoliton complexes can form when localized initial perturbations split into multiple peaks [10,11]. Furthermore, solitons can selforganize into stable patterns with an equilibrium spacing [12] or can scatter in a collision [13].Recently, polaritons, hybrid light-matter particles forming in the strong coupling regime in semiconductor microcavities [14,15], have been shown to exhibit many interesting nonlinear hydrodynamic phenomena such as superfluidity [16] and integer [17] and half vortices [18]. Microcavity polaritons are an open system far from equilibrium. Bright polariton solitons have been observed [19], which exist when an external pump fully compensates photonic losses and the decay of the excitonic coherence and are therefore termed dissipative. Polariton solitons can be manipulated on a picosecond time scale, which is promising for the development of miniature polaritonic circuits and logic gates [20]. Dark soliton trains in a 1D conservative microcavity system (no pump) were recently predicted theoretically [21], whereas dissipative polariton soliton patterns in microcavities remain unexplored.Semiconductor optical resonators are prone to growth defects and imperfections [22], and, in contrast to atomic condensates [11], the observation of multiple solitons in such systems is a challenging task, even in well-studied systems such as vertical-cavity surface-emitting lasers (VCSELs) [23,24]. In contrast to solitons in VCSELs, microcavity polariton solitons are excited at high momenta. Combined with large energy blueshifts due to the giant optical nonlinearity, this makes polariton solitons less sensitive to photonic disorder, enabling our observation of stable multisoliton patterns.Here we demonstrate the formation of dissipative polariton soliton patterns. The interplay between bistability of the external pump field, polariton-polariton scattering, and polariton negative effective mass along the propagation direction e...

Backward Cherenkov radiation emitted by polariton solitons in a microcavity wire

“…Polaritons have revealed remarkably strong nonlinear interactions and many fascinating quantum effects, including Bose–Einstein condensation 27 , 28 , superfluidity 29 and quantised vortices 30 , 31 . So-called bright dissipative polariton solitons have been reported 32 – 34 in microcavities with short polariton lifetime using a continuous wave (CW) pump holding beam that provided additional gain in order to compensate for the loss.…”

Transition from Propagating Polariton Solitons to a Standing Wave Condensate Induced by Interactions

“…However, at a higher excitation power, thermalisation can speed up due to the increased rate of polariton-polariton scattering. At P 3 = 800 µW a soliton doublet [21], corresponding to the soliton fission regime, emerges already at 10-15 ps after the excitation and remains stable until 75 ps ( Figs. 5(b,c)).…”

Nonlinear optics of coupled nanophotonic reasonators

“…Polaritons show a number of nonlinear e↵ects such as: superfluid behaviour [91][92][93], formation of quantized vortices [94][95][96], solitons [97][98][99][100][101][102], spatial nontrivial patterns [103][104][105][106][107], bistability [108][109][110][111][112], optical parametric scattering [113][114][115][116], etc.…”

“…The overall motivation of studying these solitons has been that they are expected to be useful for information processing and building blocks for polaritonic circuits [101,194]. The polariton-polariton interaction also gives rise to formation of patterns [103,105,107,159], soliton trains [195], solitons that emit radiation in the backward direction [196], etc. These patterns are also expected to play a key role in future polaritonic circuits [159,195,196].…”

“…Exciton-polaritons have been used to study a variety of fundamental nonlinear e↵ects, with a general motivation of reaching optoelectronic devices [308]. For example, a large body of work was focused on the creation and control of polariton solitons [97][98][99]101,[309][310][311], which were conjectured to play a role in devices [103,195,312] with some soliton logic gates constructed [313]. In parallel, polaritons Figure 5.2: Truth table of these three rules is given here.…”