AL2550M 25 mm Dia. N-BK7 High-Precision; CNC Polished Aspheric Lenses; EFL=50 mm; NA=0.23 Uncoated

The AL2550M is a high-precision aspheric lens offered by Thorlabs, a leading vendor in the optical industry. This lens is designed with a 25 mm diameter and a focal length of 50 mm, making it suitable for a wide range of optical applications.

The lens is crafted from N-BK7, a high-quality borosilicate glass known for its excellent optical properties. This material is particularly suitable for applications in the visible and near-infrared spectrum, making the AL2550M a versatile choice for many setups.

The aspheric design of the lens is achieved through CNC polishing, a process that ensures high surface accuracy and low scatter. This results in improved image quality and increased light transmission, which are critical factors in many optical systems.

The lens has a numerical aperture (NA) of 0.23, which is a measure of its light-gathering ability. A higher NA allows for greater resolution and a wider field of view, making this lens a good option for applications that require these characteristics.

The lens is uncoated, meaning it does not have any additional layers to enhance its optical properties. While coatings can provide benefits such as reduced reflectivity or increased durability, an uncoated lens can be a cost-effective choice for applications where these benefits are not necessary.

The lens has a thickness of 3 mm at the edge and 6 mm at the center. The inner and outer radii are 0 mm, indicating a circular shape. The lens also has higher-order aspheric coefficients up to the 16th order, which contribute to its high-quality optical performance.