Optical windows are used to transmit light and protect work areas or sensitive components from the outside environment. Optical windows use substrates, coatings, or a combination of the two to transmit specific wavelengths or ranges of wavelengths. Uncoated N-BK7 windows could also be used as substrates or blanks of mirrors. 

N-BK7 features excellent transmission from visible to NIR spectrum, low inclusion of bubbles and impure substances, and ease of manufacturing and machining. Therefore it is an excellent choice for transmission optical components. As mirror substrates, N-BK7 is also advantageous in terms of fine mechanical properties resistance to scratches, and stable chemical properties. 

North Optics’s stocked N-BK7 windows or mirror blanks including the Lambda/4 flatness modules and lambda/10 modules, while Lambda/4 flatness is low cost and suitable for most kinds of optical applications, and the Lambda/10 flatness modules are suitable for laser system and other high demanding applications.