LBTEK Quartz Optical Contact True Zero-Order Quarter-Wave Plate is commonly used to convert Linearly Polarized Light into Circularly Polarized Light. After Linearly Polarized Light passes through the True Zero-Order Quarter-Wave Plate, the generated Optical Path Difference (OPD) is λ/4, and the Phase retardance is π/2. The Design Wavelengths of Quartz Optical Contact True Zero-Order Wave Plates include common wavelengths used in fields such as laser cooling, atomic clocks, and Quantum Technologies Precision Measurement: 399 nm, 509 nm, 556 nm, 671 nm, 780 nm, 795 nm, 813 nm, 852 nm, and 1013 nm. For the Quartz Optical Contact True Zero-Order Quarter-Wave Plate with a Retaining Ring-style housing, the housing is non-detachable, and the housing surface is engraved with the Item # and the Fast Axis Marking line of the Wave Plate, making it convenient for customers to identify and use. Each Quartz Optical Contact True Zero-Order Quarter-Wave Plate is shipped with a one-to-one quality inspection report, which records the actual measured specifications of the Wave Plate (including key parameters such as Retardance and wavefront error), ensuring full traceability of product quality.