The main optical parameters of rectangular window plates include the following aspects:

Size: The length and width need to be precisely measured and labeled to meet the installation requirements of different equipment or systems. For example, common specifications include 10mm × 10mm, 20mm × 20mm, etc.

Thickness: Its value affects the mechanical strength and optical performance of the window plate, such as parallelism. It is generally determined according to specific application scenarios, with common thicknesses of 1mm, 2mm, etc.

Angle non-perpendicularity: It refers to the deviation between the angle between the two surfaces of the rectangular window plate and the theoretical perpendicular angle. It is usually required to be small to ensure the normal passage of light and the accuracy of the optical system. It is measured in radians or degrees, such as less than 0.1°, etc.

Aperture: The effective diameter through which light can pass needs to be clearly labeled for accurate use in optical systems to ensure that light passes through unobstructed.

Material refractive index: It determines the propagation speed and path changes of light in the window plate. Different materials have different refractive indices, such as the common BK7 glass with a refractive index of approximately 1.506 and fused silica with a refractive index of approximately 1.458.

Parallelism: The degree of parallelism between the two surfaces is generally represented by the beam deviation, such as less than λ/10 (λ is the laser wavelength), to ensure the accuracy of the propagation direction of light after passing through the window plate.

Surface figure accuracy: It is usually given in the form of power (λ/p), such as λ/4@633nm, indicating that the surface figure accuracy at a wavelength of 633nm is one-quarter wavelength, reflecting the flatness and optical quality of the surface.

Center thickness error: The deviation between the actual center thickness and the nominal center thickness is generally required to be controlled within a small range, such as ±0.1mm, to ensure the stability of optical performance.

Surface finish: It describes the smoothness of the surface and is usually divided into different grades. The number and size of defects such as scratches and pits are specified to ensure good optical performance and appearance.

Chamfer: The size of the edge chamfer is generally 0 to 0.2mm, serving a protective role and preventing edge damage.