Terahertz half-wave and quarter-wave plates

Terahertz waveplates are optical components specifically designed for polarization control and polarization-state conversion in the terahertz band. They are fabricated from birefringent materials such as THz-grade crystalline quartz. By introducing a specific phase retardation between the two orthogonal polarization components, these waveplates enable precise adjustment of the polarization state of terahertz radiation. The product line offers two main types: λ/2 half-wave plates and λ/4 quarter-wave plates. The half-wave plate introduces a phase retardation of π, which can be used to rotate the polarization direction of linearly polarized terahertz waves; the quarter-wave plate introduces a phase retardation of π/2, enabling conversion between linear and circular polarization. This series adopts an X-cut crystal structure, with a designed operating wavelength range of 40-1000 μm (approximately 0.3-7.5 THz). The clear aperture is ≥90 % of the effective area. Standard sizes include 20×20 mm and 50×50 mm, and customisation for a specific single wavelength and special dimensions is also supported. With excellent polarisation modulation capability and high fabrication precision, THz waveplates are widely used in terahertz time‑domain spectroscopy (THz-TDS), terahertz polarimetry, polarisation imaging, studies of material anisotropy, THz spectral analysis, and research-grade terahertz optical systems.