Extreme-ultraviolet efficiency measurements of freestanding transmission gratings

Abstract

We report new, near-normal-incidence, transmission grating efficiency results at selected extreme-ultraviolet wavelengths between 4.5 and 30.5 nm for two transmission gratings, one with a period of 200 nm and the other with a period of 400 nm. These gratings consist of opaque gold bars separated by open spaces that have been produced by photolithography techniques commonly used to produce electronic components. The gold bars and the open spaces are nominally of the same width. Both gratings have a thickness of 470 nm. The transmission efficiency at the central, first, and, when possible, second order of diffraction was measured. In addition, guided-wave phenomena at nonnormal angles of incidence, as well as transmission differences depending on which side of the grating was illuminated, were investigated. The observed guided-wave effects allow one to selectively enhance the transmission of the grating at desired wavelengths, as is realized with a blazed reflection grating.

Early Observations by the GOES-13 Solar Extreme Ultraviolet Sensor (EUVS)

“…One limitation of using a calculation for the grating transmission is that the results will produce a theoretically perfect response for the given parameters that do not include grating imperfections. While the expected response for calculated first-order transmissions was very close to that measured in similar gratings, the calculated even-order transmission is significantly smaller than measured even-order responses observed in similar gratings (McMullin et al, 2004;Ceglio et al, 1988). This has been attributed to the slight imperfections in the 1:1 gap-tobar ratio of the flight gratings.…”

“…In the absence of high-latitude forcing, the main heating and ionization sources to the thermosphere-ionosphere system come from the irradiance spanning the limits shown in Table 1. This region also accounts for most of the dayglow (Meier, 1991). During intense flares, the irradiance shortward of 5 nm can be significant and will be deposited primarily in the lower thermosphere and upper mesosphere.…”

Plasma etch fabrication of 60:1 aspect ratio silicon nanogratings with 200 nm pitch

“…Ultraviolet filtration on the medium energy neutral atom instrument for the IMAGE satellite was accomplished by gold gratings with 40 nm slits and 510 nm thickness. [1][2][3] Similar gratings were used in experiments with extreme ultraviolet ͑EUV͒ diffraction 4 and 0.5 keV electron diffraction. 5,6 High resolution x-ray spectroscopy on NASA's Chandra Space Telescope was enabled by 200 and 400 nm period gratings suspended on submicrometer thickness polyimide membranes.…”

Visualisation of details of a complicated inner structure of model objects by the method of diffusion optical tomography

“…Ultraviolet filtration on the medium energy neutral atom (MENA) instrument for the IMAGE satellite was accomplished by gold gratings with 40 nm slits and 510 nm thickness [7][8][9]. Similar gratings were used in experiments with extreme ultraviolet (EUV) diffraction [10] and 0.5 keV electron diffraction [3,11]. High resolution x-ray spectroscopy on NASA's Chandra space telescope was enabled by 200 and 400 nm period gratings suspended on submicron thickness polyimide membranes [12].…”