AC254-075-A-ML 25.4 mm Dia. N-BK7/SF5 Mounted Achromatic Doublet; EFL=75mm 400-700nm

This is the AC254-075-A-ML, a 25.4 mm diameter achromatic doublet lens from Thorlabs. The lens is designed for use in the 400-700nm spectral range, making it suitable for a wide range of optical applications.

The lens is a mounted doublet, meaning it comes with a mount for easy integration into optical systems. The mount is not specified in the data, so it's recommended to check the vendor's website for more details.

The lens is made from two types of glass: N-BK7 from Schott and SF5 from Schott. These glasses are chosen for their specific refractive indices and dispersion properties, which help to minimize chromatic aberration in the lens.

The lens has a focal length of 75mm, as determined by its effective focal length (EFL). This is a common focal length for achromatic doublets, offering a good balance between field of view and image magnification.

The lens is coated with Thorlabs' AC400-700-A coating on both the front and back surfaces. This coating is designed to improve the lens' transmission in the 400-700nm range, reducing losses due to reflection and scattering.

The lens' geometry is also specified in the data. It has a thickness of 6.9mm at the edge, with a central thickness of 7mm for the first surface and 2.5mm for the second surface. The lens' radii of curvature are also specified, with r1 = 46.5mm, r2 = -33.9mm, and r3 = -95.5mm.