Bulk Crystal Growth of Stilbazolium Derivatives for Terahertz Waves Generation

Abstract

The two stilbazolium derivatives, 4-dimethylamino-N-methyl-4-stilbazolium tosylate (DAST) and 4-dimethylamino-N-methyl-4-stilbazolium p-chlorobenzenesulfonate (DASC), are organic ionic nonlinear optical materials that have a tendency to form bulk crystals when grown in a mixed solvent of methanol and acetonitrile. We observed the generation of broadband high-power terahertz (THz) waves from the bulk crystals of DASC. DASC crystals have superior transmission characteristics in the THz band than DAST crystals, and it is expected that the THz waves generated using DASC crystals will have higher power than those generated using DAST crystals.

Experimental three-dimensional beam profiling and modeling of a terahertz beam generated from a two-color air plasma

“…The highest peak intensities are reached with ultrafast, pulsed THz sources. A secondorder nonlinearity driven by intense femtosecond laser pulses in appropriate crystals results in difference-frequency generation of intense THz pulses, with the most prominent materials currently in use being the inorganic crystals LiNbO 3 [1,2], ZnTe [3] and GaSe [4,5], and the organic salt DAST [6] and related structures such as DASC [7] and OH1 [8]. With these crystals, pulse energies up to tens of µJ and peak field strengths in the MV cm −1 range have been reported.…”

Pump-beam-induced optical damage depended on repetition frequency and pulse width in 4-dimethylamino-N ′-methyl-4′-stilbazolium tosylate crystal

“…In both the cases of 15-ns pulse duration and 600-ps duration, we demonstrated that the thermal effects in DAST crystals dominated the optical damage, which depended on thermal accumulation and dissipation. Organic nonlinear optical (NLO) crystal 4-dimethylamino-N 0 -methyl-4 0 -stilbazolium tosylate (DAST), 1,2 with its large nonlinearity, is a promising material for efficiently generating terahertz (THz) waves by second-order NLO processes such as difference frequency generation (DFG) 3-8 and optical rectification (OR), [9][10][11][12][13] as well as for detecting THz waves with high sensitivity by nonlinear up-conversion. 14 In particular, tunable THz-wave generation and monochromatic coherent detection have been developed for many THz-wave applications.…”

Growth, structural, optical and thermal properties of potential THz material: N, N-dimethylamino-N′-methylstilbazolium 4-styrenesulphonate

“…We believe that the growth of the crystal with mixed solvent of water-methanol along with the slope nucleation coupled slow evaporation method have favored the growth of good quality size crystals. In a similar manner, during the growth of N,N-dimethylamino-N 0 -methylstilbazolium p-chlorobenzenesulphonate (another DAST derivative); Matsukawa et al [5] have successfully used mixed solvents of methanol-acetonitrile to improve the size of the crystal.…”

“…By far, the generation of broadband high power THz waves from DAST single crystal has been realized up to 30 THz by difference frequency generation (DFG) and, the generation of sub-10 THz waves are achieved by optical rectification (OR) with appropriate lasers [5,6]. However, a number of absorption features in the THz spectra of DAST limits its application, for example; the strongest absorption at 1.1 THz is attributed to the TO phonon resonance and it leads to a gap in the emitted spectrum at this frequency.…”