7 May 1996 Binary-optic reflection grating for an imaging spectrometer
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A single optical element capable of both wavelength dispersion and imaging would be useful for implementing compact imaging spectrometers. We have fabricated a hybrid refractive/diffractive element that accomplishes these goals. The element is a plano-convex glass lens with a reflective diffractive surface fabricated on the planar side. The diffractive surface combines a blazed grating and several forms of aberration correction. The surface relief profile was fabricated in poly-methyl methacrylate (PMMA) by direct-write electron beam (E-beam) lithography followed by a single development step. The 8.2 mm X 8.2 mm exposure pattern was corrected for both the nonlinear dose response of the PMMA and the E-beam proximity effect. Surface characterization by atomic force microscopy revealed that the grating blaze profile was linear, although the grating was overetched. Optical characterization included diffraction efficiency measurements, knife-edge spot size measurements, and CCD spot irradiance profiles at multiple wavelengths and field positions. The measured spot and field sizes translate to a resolution of 65 wavelength channels in the 400 to 700 nm band of interest and 128 spots along the imaging direction for a 10 mm entrance slit.
© (1996) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Daniel W. Wilson, Paul D. Maker, Richard E. Muller, "Binary-optic reflection grating for an imaging spectrometer", Proc. SPIE 2689, Diffractive and Holographic Optics Technology III, (7 May 1996); doi: 10.1117/12.239629; https://doi.org/10.1117/12.239629

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