Direction dependent crystalline perfection, Z-scan studies and fabrication of Type-I and Type-II SHG elements using imidazolium L-tartrate crystals for optical modulator applications

Monoclinic phase (P21) imidazolium l-tartrate (IMLT) has received considerable research interest because of its wide transparency range, good SHG efficiency and phase matchable non-linear optical (NLO) materials. Organic single crystals of IMLT have been grown via a slow cooling method. The grown crystals were oriented using powder X-ray diffraction. The quality of the grown crystals was evaluated using HRXRD studies. Polarized Raman spectroscopy was carried out on b-cut and c-cut IMLT wafers. The third order NLO characteristics of the <1 0 0>, <0 1 0> and <0 0 1> orientated IMLT crystals have been studied using Z-scan measurements with a Hi-Ne laser (632.8 nm). The second-harmonic generation (SHG) intensity was measured for the powdered grown crystals with various particle sizes to explore the second order NLO properties and phase matchability in the crystals. Furthermore, the type-I and type-II phase-matching angle of the XY and XZ (θ <Ω) planes were calculated.