Electron-beam-fabricated asymmetric transmission gratings for microspectroscopy

Asymmetric transmission gratings operating in the resonance domain are designed by modeling of the dose-controlled electron-beam lithography process with Gaussian convolution. We aim to exceed some efficiency limit [[Eta].sub.s] over a specified spectral range and to maximize [[Eta].sub.s]. The resultant continuous-profile gratings are fabricated by electron-beam lithography and proportional reactive-ion etching into Si[O.sub.2]. We demonstrate gratings with good signal-to-noise ratio and a diffraction efficiency greater than 40% for wavelengths from 400 to 750 nm. OCIS codes: 090.1970, 050.1950, 220.3740.