Rational structural design of benzothiazolium-based crystal HDB-T with high nonlinearity and efficient terahertz-wave generation

Abstract

A new promising nonlinear optical crystal C25H25NO4S2 (HDB-T, P21 space group) exhibits significant macroscopic second-order optical nonlinearity about 1.5 times larger than that of the benchmark OH1 crystal benefiting from optimized orientated polar HDB cations. Widely tunable monochromatic terahertz-wave from 0.1 to 20 THz in the HDB-T crystal was realized for the first time.