• DCX-Lenses-UVFS-JGS-1

UV Fused Silica (JGS1)
Bi-Convex Lenses

Both surfaces of Bi-Convex or Double-Convex (DCX) Spherical Lenses are spherical and have the same radius of curvature, they are popular for many finite imaging applications. Bi-convex lenses are most suitable where the object and image are on opposite sides of the lens and the ratio of the object and image distances (conjugate ratio) is between 5:1 and 1:5 for minimizing aberrations. Outside this range, plano-convex lenses are usually preferred.

We default to use the Chinese equivalent material of fused silica, there are mainly three types of fused silica in China: JGS1, JGS2, JGS3, they are used for different application. Please refer to the following detailed material properties:
JGS1 is mainly used for optics in the UV and the visible wavelength range. It is free of bubbles and inclusions. It is equivalent to Suprasil 1&2 and Corning 7980.
JGS2 is mainly used as the substrate of mirrors or reflectors, as it has tiny bubbles inside. It is equivalent to Homosil 1, 2 & 3.
JGS3 is transparent in the ultraviolet, visible and infrared spectral regions, but it has many bubbles inside. It is equivalent to Suprasil 300.

Paralight Optics offers UV or IR-Grade Fused Silica (JGS1 or JGS3) Bi-Convex Lenses available in different sizes, either uncoated lenses or with a high-performance multi-layer antireflection (AR) coating optimized for the ranges of 245-400nm, 350-700nm, 650-1050nm, 1050-1700nm deposited on both surfaces, this coating greatly reduces the average reflectance of the substrate less than 0.5% per surface across the entire AR coating range for angles of incidence (AOI) between 0° and 30°. For optics intended to be used at large incident angles, consider using a custom coating optimized at a 45° angle of incidence; this custom coating is effective from 25° to 52°. Check the following Graphs for your references.





AR Wavelength Range:

245-400nm, 350-700nm, 650-1050nm, 1050-1700nm

Focal Lengths:

Available from 10 - 1000 mm

Minimizing Aberrations:

By Using a 1:1 Object : Image Ratio


Common Specifications:


Reference Drawing for

Double-convex (DCX) Lens

Dia: Diameter
f: Focal Length
ff: Front Focal Length
fb: Back Focal L ength
R: Radius of Curvature
tc: Center Thickness
te: Edge Thickness
H”: Back Principal Plane

Note: The focal length is determined from the back principal plane, which does not necessarily line up with the edge thickness.


Ranges & Tolerances

  • Substrate Material

    UV-Grade Fused Silica (JGS1)

  • Type

    Double-convex (DCX) Lens

  • Index of Refraction (nd)

    1.4586 @ 588 nm

  • Abbe Number (Vd)


  • Thermal Expansion Coefficient (CTE)

    5.5 x 10-7 cm/cm. ℃ (20℃ to 320℃)

  • Diameter Tolerance

    Precison: +0.00/-0.10mm | High Precision: +0.00/-0.02mm

  • Thickness Tolerance

    Precison: +/-0.10 mm | High Precision: +/-0.02 mm

  • Focal Length Tolerance


  • Surface Quality (Scratch-Dig)

    Precison: 60-40 | High Precision: 40-20

  • Surface Flatness (Plano Side)


  • Spherical Surface Power (Convex Side)

    3 λ/4

  • Surface Irregularity (Peak to Valley)


  • Centration

    Precison: <3 arcmin | High Precision: <30 arcsec

  • Clear Aperture

    90% of Diameter

  • AR Coating Range

    See the above description

  • Reflectance over Coating Range (@ 0° AOI)

    Ravg > 97%

  • Transmission over Coating Range (@ 0° AOI)

    Tavg < 0.5%

  • Design Wavelength

    587.6 nm

  • Laser Damage Threshold

    >5 J/cm2 (10ns, 10Hz, @355nm)



♦ Transmission curve of uncoated UV Fused Silica substrate: high transmission from 0.185 µm to 2.1 μm
♦ Comparison of reflectance curve of  AR-coated UVFS in different spectral ranges: showing that AR coatings provide good performance for angles of incidence (AOI) between 0° and 30°)


Reflectance curve of Fused Silica with V-Coating centered at various wavelengths and broadband AR Coating for UV, VIS, and NIR (Purple Curve: 245 - 400nm, Blue Curve: 350 - 700nm, Green Curve: 650 - 1050nm, Yellow Curve: 1050 - 1700nm)