Scale-free optics and diffractionless waves in nanodisordered ferroelectrics

Abstract

Wavelength rigidly fixes the diffraction that distorts waves during propagation, and poses fundamental limits to imaging, microscopy and communication. This distortion can be avoided by using waveguides or nonlinearity to produce solitons. In both cases, however, diffraction is only compensated, so the wavelength still imposes rigid laws on wave shape, size and soliton intensity(1-14). Nonlinearity, in turn, can introduce new spatial scales. In principle, if one is able to identify a nonlinearity that introduces an intensity-independent scale that cancels the wavelength, 'scale-free' propagation can occur. In this regime, diffraction ceases, and waveforms will naturally propagate without distortion, forming solitons of any size and intensity, even arbitrarily low. Here we provide the first experimental evidence of scale-free optical propagation in supercooled copper-doped KTN:Li, a recently developed out-of-equilibrium ferroelectric(15-17). This demonstrates that diffraction can be cancelled, and not merely compensated, thus leading to a completely new paradigm for ultraresolved imaging and microscopy

Macroscopic response and directional disorder dynamics in chemically substituted ferroelectrics

“…Here we study the dielectric response of a solid solution single crystal KLTN, a disordered ferroelectric with established out-of-equilibrium properties and giant response [25,[38][39][40]. Directional components of entropy variations are inspected using dielectric spectroscopy and Fröhlich entropy [41][42][43] (Fig.…”

Effects of doping and epitaxy on optical behavior of NaNbO3 films

“…NNO is an end member of advanced lead-free ferroelectric solid solutions (K,Na)(Nb,Ta)O 3 with the excellent piezoelectric properties and a unique diffractionless light propagation. [6][7][8] Moreover, the red-color photoluminescence (PL) can be excited by ultraviolet radiation in the Pr-doped NNO crystals and (K,Na)NbO 3 ceramics. [9][10][11] Bulk NNO possesses an orthorhombic crystal structure and exhibits an antiferroelectric behavior at room temperature.…”

Injected-charge-driven increase in electro-optic effect of KTN crystals

“…In addition, they have recently attracted growing interest because they exhibit a unique optical response as out-of-equilibrium ferroelectrics around Tc. 5,6 When the host glass of the polar nanoregions (PNRs) in KTN crystals is cooled rapidly around Tc, [5][6][7] the PNRs show an anomalously large static susceptibility, which activates the scale-free optics. 7,8 We proposed a KTN EO scanner as an application using the space-charge-controlled mode of electrical conduction.…”