69-855 12.5 mm Dia. L-BAL35 Precision Aspheric Lens; EFL=12.5mm; NA=0.5 Uncoated

This is the 69-855 model from Edmund Optics, a 12.5 mm Dia. L-BAL35 Precision Aspheric Lens with an effective focal length (EFL) of 12.5mm and a numerical aperture (NA) of 0.5, uncoated. The lens is made of L-BAL35 material from Ohara, a high-quality optical glass known for its excellent transmittance and low autofluorescence.

The lens features a base shape of a circle, with an inner radius of 0 and an outer radius of 0. The diameter of the lens is 12.5 mm, and it has a thickness of 2.11 mm at the edge and 5 mm at the center. The back focal length (BFL) of the lens is 9.35 mm.

The lens's aspheric shape is defined by its radius of curvature (R1) of 7.364 and a conic constant of -1.058074. The lens's NA is 0.5, and it has a refractive index of 1.5168 at the central wavelength of 587.6 nm. The lens's front surface has a very small aspheric departure, with an e-front value of 0.000157393, an f-front value of 4.16e-07, a g-front value of -3.72e-10, and h, j, and l-front values of 0.

The lens is uncoated, which means it does not have any anti-reflective coatings. This may result in some reflection at the air-glass interfaces, but it also means that the lens is less susceptible to damage from environmental factors.

The lens is currently in stock and can be purchased directly from the Edmund Optics website.