Generation of 193 nm ultraviolet light using quartz wavelength conversion device
National Institute for Materials Science
Sunao Kurimura, Senior Researcher at the Optronic Materials Center of the National Institute for Materials Science, Masaki Harada, Researcher at the Nikon Corporation, Muneyuki Adachi, Researcher at Nidek Co., Ltd. and co-workers have developed a wavelength conversion device based on precise laser control of twin crystal in quartz and have succeeded in generating 193 nm wavelength vacuum ultraviolet light.
Abstract
- Sunao Kurimura, Senior Researcher at the Optronic Materials Center of the National Institute for Materials Science (NIMS: President: Sukekatsu Ushioda), Masaki Harada, Researcher at the Nikon Corporation, Muneyuki Adachi, Researcher at Nidek Co., Ltd. and co-workers have developed a wavelength conversion device based on precise laser control of twin crystal in quartz and have succeeded in generating 193 nm wavelength vacuum ultraviolet light. Potential applications include semiconductor microfabrication, UV lasers for eye care and high output lasers for laser machining. Large light sources can be miniaturized to about one tenth current size, making deployment as built-in light sources possible.
- NIMS has developed a polarization reversal technology using ferroelectric single crystals and is a world leader in a research on polarization reversal wavelength conversion device. Its research on laser wavelength conversion covers a wide range of wavelength regions including mid-infrared to near infrared communication wavelengths, visible wavelength and extending to ultraviolet as well as a variety of materials, device configurations. In this work, the group has succeeded in generating 193 nm vacuum UV light with a bulk wavelength conversion device using quartz.
- Conventional ferroelectric single crystal UV wavelength conversion devices using lithium tantalite cannot be used below 260 nm due to strong absorption. For shorter wavelengths, boron materials and fluoride materials that are vulnerable to water have been used. As quartz has adequate heat and chemical stability as used in jewelry, and is transparent to light (transparent down to UV 150 nm), it is widely used for digital camera optical filters and quartz watch oscillators. However, raising efficiency has been difficult for vacuum UV wavelength generation as phase matching has not been possible, and it has not been used up to now for wavelength conversion.
- If quartz with the same structures as ferroelectric polarization reversal could be produced, phase matching would become possible and wavelength conversion devices in the UV region at wavelengths below 300 nm can be produced. Kurimura and his co-workers have succeeded in generating a polarization reversal having the same structure as inversion in precise frequency by artificially producing twin structure in quartz . Analogous to application of electric fields to ferroelectrics, a unique technique for producing an inversion structure by applying stress to quartz was developed. As twin quartz produced by the application of stress has been observed underground, research has been conducted on the possibility of earthquake prediction using such twins. A new perspective on this phenomenon has been applied to a completely different application field.
- The research results will be presented at the 71st Fall Meeting of the Japan Society of Applied Physics on September 16 (Nagasaki University).
