LBTEK achromatic half-wave plates are composed of a quartz waveplate and an MgF2 waveplate, with a spacer placed between the two. The fast axes of the two waveplates are perpendicular to each other. When a linearly polarized light beam is incident perpendicularly on the waveplate, it decomposes into ordinary (o) and extraordinary (e) rays that propagate in the original direction but with perpendicular vibration directions. The corresponding refractive indices are no and ne. Since the two types of light travel at different speeds in the crystal, the phase delay generated after passing through a waveplate of thickness d is given by δ = (2π/λ)|no-ne|d, where |no-ne|d is the optical path difference. The optical path difference generated by a half-wave plate is (2m+1)λ/2, and the phase delay is δ = (2m+1)π, where m is a non-negative integer.

The phase delay of the achromatic half-wave plate is the result of both the quartz and MgF2 waveplates. By designing the thicknesses of the two waveplates, the phase delay of the achromatic half-wave plate is made to be π. The fast axis direction is determined by the waveplate that produces the larger phase delay.

LBTEK achromatic half-wave plates are commonly used to rotate the polarization direction of linearly polarized light. Compared to other LBTEK half-wave plates, achromatic waveplates are less sensitive to wavelength. They are available in design wavelength ranges of 400 nm–700 nm, 700 nm–1100 nm, and 1100 nm–1650 nm. Additionally, LBTEK's achromatic waveplates come with a non-removable mechanical housing, making them convenient for use.

LBTEK achromatic half-wave plates are commonly used to rotate the polarization direction of linearly polarized light without changing its intensity. When linearly polarized light passes through the achromatic half-wave plate, the optical path difference generated is λ/2, and the phase delay is π. The achromatic half-wave plates with installed housings feature non-removable mechanical enclosures, and the surface of the housing is engraved with the product model and fast axis identification line, making it easy for customers to identify and use the waveplate.