66-189 30 mm Dia. N-BK7 Ultra-Thin Protective Flat Window; t=0.2 mm Uncoated

The 66-189 is a 30 mm diameter uncoated ultra-thin protective flat window, designed and manufactured by Edmund Optics. This window is made from N-BK7, a popular borosilicate glass known for its excellent optical properties, including a high Abbe number and low coefficient of thermal expansion.

The window features a base shape of a circle, a geometry that is often preferred in optical systems due to its symmetry and ease of alignment. The diameter of the window is 30 mm, making it suitable for a wide range of applications that require a compact yet robust optical component.

The thickness of the window is a mere 0.2 mm, classifying it as an 'ultra-thin' window. This thinness offers several advantages, such as reduced weight, minimized optical aberrations, and improved transmission due to the reduced path length.

The window is uncoated, meaning it does not have any anti-reflective or other coatings. While coatings can enhance the performance of an optical component, an uncoated window can be advantageous in certain applications, such as when cost, simplicity, or specific wavelength transmission are primary concerns.

The window is designed to operate at a wavelength of 587.6 nm, which is in the yellow-green region of the visible spectrum. This makes it suitable for applications that operate in this wavelength range, such as fluorescence microscopy or certain types of laser systems.