The LBTEK Achromatic Depolarizer consists of two circular quartz wedge crystals, with the optical axes of the two crystals at a 45° angle to each other. The thickness ratio between the thick wedge crystal and the thin wedge crystal is 2:1, and the crystals are bonded together using the UV-curing adhesive. The achromatic depolarizer is a passive polarization component that converts the polarized light into the unpolarized light. For the monochromatic light, when a linearly polarized monochromatic beam with a certain diameter passes through the achromatic depolarizer with a gradient phase difference, the phase difference or rotation angle of the emergent light varies at different positions, resulting in different polarization states of the beam. This alters its ordered state, reducing the degree of polarization of the emergent light. For the broadband light, as the incident light contains various wavelengths, passing through the achromatic depolarizer with a certain gradient phase difference introduces different phase delays, transforming the emergent light into elliptically polarized light with varying ellipticities. The entire beam becomes a synthesis of random states, causing the emergent light to appear depolarized, i.e., achieving an integrated depolarization effect in the frequency domain. The depolarization performance of the achromatic depolarizer is related to the operating wavelength, material, angle between optical axes, and prism wedge angle. Light emerging from an achromatic depolarizer exhibits a deterministic state, in contrast to natural light, whose polarization state is random. Generally, as long as no single polarization state dominates, the depolarization effect is considered achieved. Achromatic depolarizers are widely used in laser processing, fiber-optic gyroscopes, fiber-optic sensors, high-precision spectrophotometers, photoelectric detection technologies, Raman amplifiers and etc. Currently, LBTEK achromatic depolarizers are mainly divided into two uncoated and coated versions. The uncoated versions cover a wavelength range of 190 nm–2500 nm, while the coated versions are available within the ranges of 400 nm–700 nm, 700 nm–1100 nm, and 1100 nm–1650 nm.