Parametric wave interaction in one-dimensional nonlinear photonic crystal with randomized distribution of second-order nonlinearity

Abstract

We theoretically study the parametric wave interaction in nonlinear optical media with randomized distribution of the quadratic nonlinearity χ (2) . In particular, we discuss properties of second and cascaded third harmonic generation. We derive analytical formulas describing emission properties of such harmonics in the presence of χ (2) disorder and show that the latter process is governed by the characteristics of the constituent processes, i.e. second harmonic generation and sum frequency mixing. We demonstrate the role of randomness on various second and third harmonic generation regimes such as Raman-Nath andČerenkov nonlinear diffraction. We show that the randomness-induced incoherence in the wave interaction leads to deterioration of conversion efficiency and angular spreading of harmonic generated in the processes relying on transverse phase matching such as Raman-Nath interaction. On the other hand, theČerenkov frequency generation is basically insensitive to the domain randomness.

Čerenkov-type second-harmonic spectroscopy in random nonlinear photonic structures

“…In recent years, much attention has been devoted to investigate second-harmonic generation via quasi-phase matching in crystals with a random distribution of their ferroelectric domains, i.e. with a random distribution of the χ (2) nonlinearity [1][2][3][4][5][6]. This new class of random nonlinear photonic crystals offers a versatile way to realize frequency conversion processes over a wide spectral range [7][8][9].…”