Planar diffraction gratings target laser system apps

Shimadzu Corp. has unveiled a series of planar diffraction gratings aimed at laser system applications. The customisable 'LA series' planar gratings claim to offer high diffraction efficiency of more than 90 per cent for near infrared wavelength laser compressor applications. According to the firm, its diffraction gratings are used in analytical instruments for research in the life sciences, chemistry, environmental monitoring, as well as synchrotron radiation and optical communications applications.

Shimadzu will produce customised gratings in accordance to customer requests for specific coating properties, and substrate and external shapes, for the production of gratings with the desired, highly specific characteristics. The "LA Series' line up was developed specifically for laser applications and is expected contribute to advances in laser processing and medical research.

Diffraction grating elements separate 'white light', which contains many different wavelengths of light, into separate wavelengths. Typically, diffraction gratings consist of a substrate surface ruled with highly ordered grooves with a density of hundreds to thousands of grooves per millimeter. Diffraction gratings are key devices for the extraction of specific wavelengths of light from multi-wavelength light sources for a wide range of industrial applications.

The "LA series" features groove shapes that are designed to attain the highest efficiency for TM polarized light for each laser wavelength band. These device characteristics are particularly suitable for external resonators and cavities, and pulse control.

In particular, diffraction grating elements for 633-1064nm waveband with 1600lines/mm, exhibit a diffraction efficiency of 98 per cent—the highest in this category of technology. This feature is important for expansion and compression of laser pulses for light sources used in laser processing.

The company said it has developed nine types of diffraction gratings covering laser wavelengths from the visible to near infrared for a range of applications. The diffraction gratings are replicas of high precision masters by using two light interference exposure and reactive ion-beam etching technology, thus ensuring a stable supply of gratings and excellent cost performance.