Click here to view the GRADIUM^® Lenses section of our 2008 Product Catalog.

GRADIUM^® lenses are made from LightPath's proprietary axial gradient index glass. Its unique refractive qualities can be exploited to reduce spherical aberrations - resulting in performance similar to single term aspheres. GRADIUM^® lenses provide a cost-effective solution for many high-performance applications.

Ideal for high power applications, GRADIUM^® lenses and their gradient-index structure often allow a GRADIUM^® singlet to replace a conventional spherical doublet. GRADIUM^® lenses can be custom designed for visible or near infrared applications in diameters from 5mm to over 100mm. GRADIUM^® doublets are also available for better achromatic performance and can equal the performance of conventional triplets.

In high performance optical systems, spherical aberration, chromatic aberration and astigmatism induce sweat on the brows of optical designers. These aberrations can prevent optical systems from reaching their full potential. Avoiding these factors in optical systems is often difficult without using multiple lens elements. LightPath's unique line of GRADIUM^® optics makes correcting these aberrations with a single optical element a practical reality. GRADIUM^® lenses are made from LightPath's proprietary axial gradient index glass. Its unique refractive qualities can be exploited to reduce spherical aberrations - resulting in performance similar to single-term aspheres.

GRADIUM^® lenses have been applied as simple singlets or doublets in complex multi-element systems. They have been very well received for use in high-power industrial laser systems; many of the world's largest Nd:YAG and fiber laser manufacturers now incorporate GRADIUM^® optics in their laser delivery systems. LightPath's DuraYAG™ assemblies provide a drop-in replacement for focusing and collimating assemblies on some of the most popular YAG laser systems. Their unique coverplate design extends the life of the assembly while the GRADIUM^® lens provides a smaller focused spot size, increasing power density at the workpiece and enhancing overall system performance.

LightPath would be happy to design a custom GRADIUM^® lens to meet your individual specifications. We can customize the focal length, diameter, and design wavelength to meet your specific needs. Lenses can also be provided with custom anti-reflective coatings or mounted in custom housings.

GRADIUM^® lenses take advantage of recent advances in the manufacturing of axial gradient glass. Large diameter blanks are fabricated with index changes (Δn) of up to 0.15, about 100 times that available from radial GRIN (GRadient INdex) technology. The large range in Δn available provides a substantial ability to correct aberrations, especially spherical.

The process used to produce the GRADIUM^® glass turns a series of SF glass layers into a single piece of gradient material. Unlike radial GRIN lenses, this process provides large diameter optical blanks with controlled index and dispersion profiles. Proper gradient profile selection allows a simple spherical lens to act as an asphere.

GRADIUM^® lenses should be used wherever small spot size, high numerical aperture (NA), increased beam energy, or excellent wavefront quality are important. A GRADIUM^® singlet does not have the limited laser damage threshold of a conventional cemented doublet, so laser power can be increased, leading to increased production throughput.

GRADIUM^® glass offers the additional benefit of chromatic correction. The dispersion, as well as the optical index, varies in a controlled fashion within the lens. A finished lens can be viewed as a seamless, contiguous combination of many glass types. This continuous variation results in a transfer aberration correction not possible with homogeneous lenses. By combining GRADIUM^® flint glass with a homogeneous crown glass, achromatic doublets are fabricated with superior color correction.

Anti-Reflective Coatings

All of LightPath's Nd:YAG lenses and modules are available with high quality anti-reflective coatings. The VC-8 coating is designed to withstand the high power, rugged environment of YAG laser manufacturing. Reflectivity is typically less than <0.15% per surface and guaranteed to be <0.25% at 1064nm. GRADIUM^® lenses and DuraYAG™ modules have been tested at the Fraunhofer Institute and are suitable for applications up to 4000 watts CW. If you need coatings for applications which are greater than 4000 watts CW, a LightPath representative would be happy to discuss your requirements.

24-Hour Quick Replacement Priority Plan

LightPath's Quick Replacement Priority Plan provides 24 hour delivery of your DuraYAG™ module to replace an assembly that has failed. LightPath offers GRADIUM^® lenses and modules off-the-shelf for most common YAG laser systems and heads including Trumpf^®, Rofin-Sinar^®, GSI Lumonics^®, Precitec^® and others. Customized optics and modules can also be designed for your specific application.