Proximity-compensated, as well as uncompensated, blazed transmission gratings with periods of 4, 8, and 16 μm were manufactured with direct-writing, electron-beam lithography in positive resist. The compensated gratings performed better than the uncompensated ones. For the 4-μm compensated grating the measured diffraction efficiency was 67%. It was 35% for the uncompensated grating. The compensation was made by repeated convolutions in the spatial domain with the electron-beam point spread function. We determined this function by retrieving the phase from the measured diffraction pattern of the uncompensated gratings.
- Blazed phase gratings
- Diffractive optics
- Electron point-spread function
- Electron-beam lithography
- Proximity compensation