New pressing technique from SCHOTT enables high precision mass production of diffractive optical elements from glass for the first time.
Until now, diffractive optical elements for mass production could only be manufactured out of plastic, with all of its known weaknesses, including high scattering losses, low resistance to temperature, moisture, lasers and chemicals. Now, SCHOTT has come up with an alternative. The international technology group based in Mainz is now manufacturing diffractive optical elements from optical glass. These elements are extremely precise and efficient and can be manufactured in larger quantities using the precision blank molding technique.
One can hardly imagine modern optical systems of lasers, sensors, lighting and imaging devices without diffractive optics. These extremely small elements that diffract the light inside minute spaces and bundle it into beams with exact shapes and direct it in the desired direction represent the key to miniaturization of optical systems. Until now, these elements for serial applications have been manufactured using plastic or fused silica with the help of sophisticated and, therefore, expensive lithography techniques and etching processes.
New diffractive optical elements (DOEs) made from high index glass from SCHOTT feature high diffraction efficiency of up to 95 percent. They also exhibit high mechanical, thermal and chemical durability and make it possible to combine various optical functions inside a single element. DOEs can be produced for use as blazed diffraction grating, computer generated holograms (CGH) and Fresnel zone lenses.
The precision glass molding that is now being used by SCHOTT to produce the DOEs, is at the heart of the unique manufacturing process, it has been used for years to manufacture large aspherical lenses for sensors, cameras and projectors, yet has also proven itself in manufacturing micro lenses.
Now, SCHOTT has succeeded in using the precision molding technique to manufacture diffractive optical elements and pressing the contours of the highly precise shaping tool onto the surfaces of glass thousands of times in an identical manner. “No other company is capable of manufacturing these types of optics with such reproducible precision,” notes Helge Vogt, New Products Manager at SCHOTT AG. The new diffractive optical elements are available now.