AL1225M 12.5 mm Dia. N-BK7 High-Precision; CNC Polished Aspheric Lenses; EFL=25 mm; NA=0.23 Uncoated

The AL1225M is a high-precision aspheric lens offered by Thorlabs, designed with a 12.5 mm diameter and a unique N-BK7 Schott material ID. This lens is specifically engineered for use in the 780 nm wavelength range, making it suitable for various applications that operate within this spectrum.

The lens boasts an effective focal length (EFL) of 25 mm, which is a crucial factor in determining the lens's overall magnification and field of view. Additionally, the lens has a numerical aperture (NA) of 0.23, which indicates its ability to gather and focus light, ultimately influencing the resolution and contrast of the resulting image.

The aspheric design of the AL1225M allows for improved optical performance compared to traditional spherical lenses. This is achieved by reducing spherical aberration, a common issue that can lead to distorted images. The lens's geometry includes an inner radius of 0, an outer radius of 0, a thickness at the edge of 2.5 mm, and a thickness at the center of 4 mm.

The lens's front surface is defined by the conic constant k1 (-0.6) and a series of aspheric coefficients (a2 to a16), which further enhance its optical performance. The absence of a coating on this lens indicates that it is uncoated, meaning it does not have any additional layers to reduce surface reflections or protect the lens from environmental factors.