66-191 50 mm Dia. N-BK7 Ultra-Thin Protective Flat Window; t=0.2 mm Uncoated

The 66-191 is a 50 mm diameter uncoated ultra-thin protective flat window, designed and manufactured by Edmund Optics. This window is made from N-BK7, a popular optical glass known for its excellent optical properties, high homogeneity, and low optical dispersion. The window is uncoated, providing a cost-effective solution for applications where anti-reflective coatings are not required.

The window features a base shape of a circle, a standard in optical systems due to its symmetry and ease of alignment. The geometry of the window includes a diameter of 50 mm and a thickness of 0.2 mm, making it an ultra-thin window. This thinness is beneficial in applications where weight and space are critical factors.

The window is designed to operate at a wavelength of 587.6 nm, which is in the yellow-green part of the visible light spectrum. This makes it suitable for applications in the visible light range, such as imaging, metrology, and beam delivery systems.

The window has a shape of a thin lens, which means it has a curved surface, although in this case, the curvature is so slight that it functions primarily as a window rather than a lens. This shape can provide some focusing or collimating effect, depending on the application.