Diffraction gratings have various optical properties such as dispersion, polarization, anti-reflection, and waveguiding, and are widely used in astronomical spectroscopy, holographic display, precision measurement, and other applications. The interference lithography method based on a phase mask uses the interference between diffracted orders of the phase mask to produce periodic patterns. Compared with conventional interference lithography, it has the characteristics of a simple and compact structure of the exposure system. The feature size of the transferable pattern is small, and currently, up to several hundred nanometers can be resolved and prepared; the grating parameters are repeatedly stable and suitable for producing a small number of gratings. First, this method is valuable in replicating diffraction gratings at low cost and high productivity. Moreover, combined with meta-structured phase masks, it can still have academic potential in preparing complex meta-structured patterns.
We report on high-efficiency visible and near-infrared transmission gratings in fused silica generated by holographic recording and reactive ion beam etching technology. At a wavelength of 740 nm, near 100% diffraction efficiency is achieved under Littrow conditions. The design is based on the phenomenon of the high aspect ratio gratings by using the rigorous coupled wave analysis. A binary grating with the optimum grating period of 740 nm and groove depth of 1.55 had been fabricated in the paper. The grating wavelength bandwidth and angular bandwidth are extremely enhanced compared with conventional volume phase holographic gratings, making these gratings the key elements in high-resolution astronomical ground-based telescope spectrographs.
Fabrication-induced metal contaminations and subsurface damage are generally identified as the laser damage initiators
that are responsible for the laser induced damage in fused silica. In this paper, the removal of those two initiators are
realized by two methods: wet chemical surface cleaning and optimized HF-based etch process. Two kinds of chemical
leaching are used to removing the Ce and other metal impurities respectively. In order prevent the redeposition of the
reactive byproducts during HF etch process, we optimized the traditional HF etch process in two ways: absence of NH4F in etch solution and presence of megasonic and ultrasonic agitation during and after etch respectively. And laser damage tests show that these two treatments greatly improve the laser damage resistance of fused silica.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.