Biconvex Lenses (Stocked)

A Biconvex Lens, also known as a Double Convex Lens, is an optical lens with two spherical sides that have the same curvature radii. The major uses of  Biconvex lenses include laser beam modulation, light focus, and imaging. Biconvex lenses have positive focal lengths and converge collimated light to a point. When the absolute finite conjugate ratio is equal to or near 1:1, biconvex lenses are advised. When the object distance and image distance are equivalent in absolute terms, biconvex lenses are the best option for conjugate ratios between 1:5 and 5:1. If not, plano-convex lenses are preferable since their asymmetric shapes help to reduce spherical aberrations. The focal lengths of the biconvex lenses could be calculated using the formula: f= (R1*R2)/((n-1)*(R2-R1)).

N-BK7 or its equivalent known as H-K9L is a ROHS-compliant borosilicate crown glass with a high transmission rate in the spectral range from visible to near-infrared (350-2200nm) and is probably the most frequently-chosen optical glass to manufacture professional optical components. The most attractive advantage of N-BK7 is its high optical homogeneity, which means its refractive indexes will only vary within a small amplitude. Besides, the hardness, chemical, and aberration resistance of N-BK7 are also very remarkable, it contains low levels of inclusions and bubbles, therefore N-BK7 is excellent for making high-precision optical lenses.

UV Fused Silica, equivalently known as JGS1, is an optical glass material with incomparably superior transparency to the UV wavelengths, meanwhile also being transparent to visible and NIR radiations (transmission range 200-2200nm). In fact, UV Grade Fused Silica is one of the best ultraviolet-transmitting media. The thermal properties of UVFS are prominent, too, including high-temperature durability and low thermal expansion. Other benefits of UV Fused Silica lenses encompass few bubbles/striae, high homogeneity, and advantages of birefringent properties. Therefore UVFS lens is the primary option for building a stable optical system under harsh working conditions.

This page features Shalom EO‘s Stocked N-BK7 Biconvex Lenses and UV-Fused Silica Biconvex Lenses. Within our stock list, a wide range of focal lengths of 10-1000mm and diameters of 5.0-50.8mm are broadly available. However, custom biconvex lenses made from BaF2, CaF2, MgF2, Ge, ZnSe, Sapphire, and other optical materials are also procurable upon your request. 

Regarding the N-BK7 Biconvex Lenses, the original transmission range of uncoated N-BK7 is 350-2200mm, with an absorption dip positioned at around 2.8 microns. To further enhance the transmission of the N-BK7 double convex lens, Broadband Anti-reflection (BBAR) coatings could be furnished to accommodate the requirements for multi-wavelength and tunable lasers. Besides the uncoated versions, we also provide standard N-BK7 double convex lenses with three kinds of broadband AR coatings: 350-650nm, 650-1050nm, and 1050-1580nm to increase the transmission and elevate the efficiencies of utilization. Regarding the UV Fused Silica Biconvex Lenses, the UV Fused Silica double convex lenses in our stock list are uncoated, To further enhance the transmission of the UV Fused Silica double convex lenses, designed coatings could be tailored according to customers’ requirements. In addition to the conventional BBAR coatings mentioned above, Shalom EO also provides V coatings consisting of multiple high-performance layers to obtain minimum reflectance over a contracted spectral range and low-cost MgF2 coatings.

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