ACT508-250-A 50.8 mm Dia. N-BK7/N-SF2 Unmounted Achromatic Doublet; EFL=250mm 400-700nm

The ACT508-250-A is a high-quality achromatic doublet lens, unmounted and with a diameter of 50.8 mm, sourced from the renowned optical components manufacturer, Thorlabs. This lens is designed for use within the 400-700nm wavelength range, making it suitable for a wide array of applications within the visible light spectrum.

The lens features a design comprising two components: N-BK7 and N-SF2 Schott glasses. These materials have been carefully selected to minimize chromatic aberration, a common issue in optical systems where different wavelengths of light are focused at different points. By combining these materials, the ACT508-250-A achieves excellent achromatic performance, ensuring that light of different wavelengths is focused accurately at a single point.

The lens has an effective focal length (EFL) of 250mm, a crucial specification determining the lens's magnification power. This EFL makes the ACT508-250-A a versatile lens, suitable for various applications that require moderate magnification.

The lens's geometry is characterized by a 12.3mm edge thickness, 9.3mm center thickness for the first component, and 6mm center thickness for the second component. The lens's base shape is circular, and it features inner and outer radii of 0mm, indicating a symmetrical design. The first and second radii of curvature are 131.2mm and -116mm, respectively, while the third radius of curvature is -538.1mm.

The ACT508-250-A is coated with Thorlabs' AC400-700-A coating on both the front and back surfaces. This coating enhances the lens's transmission within the 400-700nm range, reducing unwanted reflections and improving overall system performance.