Abstract
We report on simulations and measurements of focusing diffractive optical elements, fabricated as two-level binary optics. The diffractive optical elements are designed to separate and focus four specific wavelengths in the infrared. The simulations are based on a local linear grating model, and predict anomalies similar to Wood's anomalies known from grating diffraction theory. The anomalies are also seen in the measurements, and are excited at the DOE locations predicted by the simulations. The given examples illustrate the usefulness of the model for evaluation of DOE designs. We also present a comparison of the response and spectral uniformity between two different versions of the four-wavelength diffractive optical elements. In the first version, the optical functions for all the four wavelengths are incorporated into the same surface pattern, covering the whole patterned area. In the second version the pattern f each wavelength is kept separate, and cover one fourth of the area, forming a mosaic of the four individual patterns.
Highlights
Diffractive optical elements (DOEs) are useful components in small, lightweight and low-cost spectrometer systems
We have measured the spectral response of two-level diffractive optical elements (DOEs) that have been fabricated in silicon and coated with gold
It was proposed that this could be due to the roughness of the groove walls in the two-level surface patterns mélange DOE studied in that paper, or due to the mixing of patterns in mélange
Summary
Diffractive optical elements (DOEs) are useful components in small, lightweight and low-cost spectrometer systems. It was proposed that the reason this anomaly was not sharply localized could be due to two effects not included in the model These effects were the significant roughness of the grooves in that particular two-level DOE, and the mixing of the surface patterns for different wavelengths in the multi-wavelength (mélange) DOE. We show in this paper that both anomalies appear in the measurements when the DOEs are fabricated with smooth groove walls This further increases the usefulness of the local linear grating model used in [3] and the present paper, and shows that resonance anomalies can be excited for ideally fabricated multi-wavelength focusing DOEs. In Section 2, we briefly present the fabricated DOEs and the measurement setup.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
