The holographic lithography - ion beam etching is adopted to fabricate the nanoimprint template with periodic structures. The accurate control of the high aspect ratio of the profile is achieved by the optimization of the holographic lithography and the choice of the appropriate parameters of ion beam etching. There are two major challenging steps of this method: 1) the holographic exposure and development in the fabrication of the photoresist mask and 2) the ion beam etching to transfer the photoresist mask to the fused silica. The experiment indicates that titled rotation of the ion beam etching combined with reactive ion beam etching can achieve the accurate control of the high aspect ratio structure. Two types of nanoimprint template have been fabricated: the period of 250nm and the groove depth of 380nm; the period of 600nm and groove depth of 1400nm, respectively.
A holographic dual-blazed grating with the period of 833 nm at ultraviolet-visible-near infrared was designed. To
achieve higher and uniform diffraction efficiency, the grating profile was optimized by using rigorous coupled-wave
analysis. The results show: when the two blaze angles of the dual-blazed grating, one within the range from 10 degree to
12 degree and the other one within the range from 26 degree to 32 degree respectively, the first-order diffraction
efficiency is more than 30 percent within the wavelength from 0.25μm to 1μm. The holographic dual-blazed grating, one
half with the blaze angle of 11 degree and the anti-blaze angle of 72 degree; and the other half with the blaze angle of 29
degree and the anti-blaze angle of 56 degree respectively, have been fabricated by improved holographic ion beam
etching.
The Offner-like spectrometer, one most widely used hyperspectral imaging spectrometers, offers some advantages
over other spectrometers used in pushbroom imaging spectrometry: low chromatic aberrations, a compact size with low
optical distortion, and large numerical aperture. The standard Offner spectrometer is made of three spherical concentric
elements-- two concave mirrors and one convex grating. Convex grating is the core part of Offner type hyper-spectral
imager. Considering the difficulties in fabrication of small angles convex gratings by traditional ways, we propose a new
method. The ion-beam-etching holographic grating is adopted to obtain the convex blazed gratings with blazed angle of
4°--5°, whose angle can be further reduced by dipping or spinning coating with hardenable liquids. A highly
reproducible blaze angle reduction to as high as a factor of 3 is achieved by controlling the spinning speed and viscosity
of solution. The precise control of the blaze angles and groove profiles will be further studied focusing on the designing
of rotate dip equipment and optimization of pulling speed and viscosity of solution.
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.