Aspheric Lenses

Aspheric Lens is an optical lens with the geometries of a non-spherical optical front (that is, the radius of curvature varies with the distance from the optical axis). The unique feature of an aspheric lens is the minimized spherical aberrations. Spherical aberrations intrinsic in spherical lenses, due to differences in the optical paths, the focal points of lights closer to the optical axis tend to be more forward than that of the lights incident at the edges of the spherical lenses, resulting in blurring of the image and increasing spot width. Compared with spherical lenses, Aspheric lenses exhibit spherical aberrations reduced to a dramatic extent, leading to enhanced image resolution, and spot diameters that are several orders less than the spot diameter of spherical lenses. An aspheric lens allows a larger numerical aperture (low f-number) and therefore increases the light throughput, achieving higher power efficiencies. Incorporation of aspheric lenses into lens modules also could help to reduce the element number with the exemption of excessive optics for correction of spherical aberrations, enabling compact and simplified design.

Hangzhou Shalom EO offers custom Aspheric Lenses made of various materials including optical glass materials (e.g. N-BK7, Fused Silica), and Germanium, Zinc Selenide, Silicon for infrared wavelengths. The preforms of our aspheric lenses could be plano-convex/plano-concave lenses, ball/half lenses, achromatic lenses, etc. The lenses are manufactured using Computer Numerical Control (CNC) precision polishing and grinding machines, whilst for bulk-production of glass lenses, precision glass molding is utilized to obtain efficient productiveness in short timescales. For non-glass aspheric lenses, more stringent precision control could be achieved using single-point diamond turning (SPDT) techniques. The transmission of our aspheric lenses extends from UV to NIR, and diameters are available between 5mm and 300mm. Custom coating options of Shalom’s aspheric lenses include uncoated substrates, Broadband Anti-reflection (BBAR) coatings that effectively reduce reflection (average reflection below 0.5%) over a certain wavelength range, and laser line V-coating which provides higher transmission (average reflection below 0.25%) at a narrower range around a certain wavelength, and MgF2 AR coatings (average reflection below 1.5%) with competitive low price.