Quasi-phase matching harmonic generations in short-range ordered nonlinear photonic crystal [7027-65]

A novel design of reversed domains in a short-range ordered manner by placing randomly oriented basic units on a square lattice is propose and demonstrated. The corresponding reciprocal space is characterized not only by discrete diffraction peaks, but also by the continuous RVs distribution as homocentric rings. Then continuous nonlinear process is available as long as its wave vector mismatch falls within the region of continuous RV. In experiment the measured SHG tuning was so broad that it contains almost all frequencies in the visible range. The conversion efficiency was ~13% in the red and yellow wave bands, which is much higher than that generated in disordered NPC. Moreover, practically no any drop of the efficiency occurred even though the incident direction or sample temperature varies over a large range (50°C and 18°). Advantage of such a short-range ordered structure is demonstrated in collinear cascaded third harmonic generation (THG) at 1577 nm fundamental wavelengths.