| 摘要 |
PURPOSE:To increase both the image resolution and brightness for the concave holographic diffraction grid spectroscope, by locating the incident slit on nearly the 2-equally divided lines of the angle of rotation of the grid to the shortest and longest wavelengths to be measured and then the space between the grid and the incident slit is set larger than that between the grid and the radiation slit. CONSTITUTION:The record light sources l and l' are located on the single side of the line connecting the grid center Q and the grid curvature center C for the holographic grid having the central wavelength of the measuring wavelength region (200-900n m). In the grid thus produced, the diffraction image comes on the curve I outside the Rowland circle R in case the incident slit is located on the circle R. If the grid is deflected around its center O, an appropriate part on the I moves on the I to cause a small astigmatism in comparison with the case the diffraction image is formed on the circle R. The incident slit is set on the 2-equally divided lines of the angle of rotation to the shortest and longest wavelengths in the measuring wavelength region. And at the same time, the space (r) between the grid and the incident slit A is set larger than the space (r') between the grid and the radiation slit B. As a result, both the image resolution and the brightness can be increased. |
