Figure 2. Optimal crystal characteristics for THz generation.

(a) Solubility curve of HMQ-TMS in methanol. (b) Photograph of a large HMQ-TMS crystal grown by slow cooling method with spontaneous nucleation at a saturation temperature of 40°C in methanol. (c) Photographs of HMQ-TMS crystals after cleaving along the crystallographic ac-plane by a diamond knife. The polar axis, which is presented by the solid vector, is in the ac-plane. (d) AFM image (40 × 40 μm²) of the cleaved surface. (e) Transmission spectrum of a cleaved HMQ-TMS sample with a thickness of 0.14 mm without polishing, using unpolarized light.