LED bulb placed in a coffee cup

Whether it's on the desk or on the bedside table, it's a nice embellishment.

Achromatic lenses are a combination of a positive low refractive index (corona crown ) and negative high refractive index (flint). Compared with monolithic singlet lens the doublet design can provide users with additional design freedom and further optimize the performance of the lens. Therefore, the advantages of achromatic lenses are more significant than those of single lenses with equal diameter and focal length.
Achromatic Lenses are used to minimize or eliminate chromatic aberration. The achromatic design also helps minimize spherical aberrations. Achromatic Lenses are ideal for a range of applications, including fluorescence microscopy, image relay, inspection, or spectroscopy. An Achromatic Lens, which is often designed by either cementing two elements together or mounting the two elements in a housing, creates smaller spot sizes than comparable singlet lenses.
Realpoo Optics offer doublet achromatic lens, triple achromatic lens, square achromatic lens, micro achromatic lens, edge blackening achromatic lens etc.