Home > News > Waveplate Fabrication and Construction
Waveplate Fabrication and Construction

zero order/multiple order/achromatic optical waveplate

Waveplates are particularly challenging optical components to manufacture. They are made of crystalline materials that must be cut with their axes oriented within a few arcminutes. Then, they must be polished to a laser-quality finish, arcsecond parallelism, and <λ/10 wavefront. There is no room for correction, as their thickness tolerance is a small fraction of a micron. To verify retardation tolerances, specially-trained optical technicians use purpose-built test gear. After anti-reflective coating, zero order and achromatic waveplates are matched in pairs and accurately aligned to each other within their cell mounts.

Quartz waveplates are ideal for applications requiring high damage thresholds and retardation stability over temperature change, such as for use with lasers or infrared light sources.

Polymer waveplates consist of thin polymer sheets laminated between two glass plates, and provide many of the benefits of zero order designs including excellent angular field-of-view and lower sensitivity to incidence angles than comparable quartz waveplates. While the glass plates increase durability and ease handling, many polymer waveplates contain adhesive layers and are therefore not recommended for high power laser or high temperature applications.

Multiple order waveplates consist of a single plate, either unmounted or edge mounted to an aluminum cell. Two common construction methods exist for Precision Zero Order Waveplates and Achromatic Waveplates.

The first method utilizes an air gap where the two plates, coated on all faces, are mounted on opposite sides of a spacer and then placed within a cell. Typical beam deviation is <0.5 arcseconds. It is important to note that power handling, especially for pulsed lasers, is highly suggested when using waveplates constructed with air gaps.

The second method involves cementing achromatic lenses together with a transparent layer of optical cement across their full diameters. Then, an anti-reflection coating is applied to only their outer surfaces. Transmitted wavefront is <λ/4 at 633nm; beam deviation is <1 arcminute.