49-102 25 mm Dia. L-BAL35 Precision Aspheric Lens; EFL=25mm; NA=0.5 BBAR 425-675nm

This is the 49-102 model from Edmund Optics, a high-precision aspheric lens with a 25 mm diameter. The lens is made from L-BAL35, a material from Ohara with excellent optical properties. The lens has a numerical aperture (NA) of 0.5, which is a measure of its light-gathering ability. The effective focal length (EFL) of this lens is 25mm, making it a versatile choice for many optical applications.

The lens features a broadband anti-reflection (BBAR) coating, which is designed to reduce reflection losses over a wide range of wavelengths, specifically from 425nm to 675nm. This coating enhances the lens's performance in transmitting light, making it more efficient in various applications.

The lens's geometry is carefully designed with an inner radius of 0 and an outer radius of 0, ensuring optimal light transmission. The thickness at the edge is 1.74mm, and the thickness at the center is 7.5mm. The lens's front and back surfaces are both coated with the same BBAR coating.

The lens's asphereicity is defined by its shape, which is a departure from a perfect sphere. This design allows for the correction of spherical aberration, a common optical problem where light rays fail to meet at a single point, resulting in a blurred image. The asphereicity of this lens is defined by its k1 value of -1.439137, which is a measure of the degree of asphericity.