Abstract:
A polycrystalline diamond thin film which has an average particle size of at least 1.5 mu m and a peak intensity in the vicinity of wavelength of 1580 cm in a Raman spectrum obtained by a Raman spectroscopy having a ratio of up to 0.2 with respect to a peak intensity in the vicinity of wave number of 1335 cm . A photocathode (2) and an electron tube (1) are each provided with the above polycrystalline diamond thin film as a light absorbing layer (22).
Abstract:
The electron tube includes a vacuum container having a light transmitting substrate, a photocathode provided on an inner surface of the light transmitting substrate, an anode provided in the vacuum container, and a prism. The prism includes a bottom surface bonded to an outer surface of the light transmitting substrate, a light incident surface, and a light reflecting surface configured to further reflect light, which is incident to the photocathode through the prism and the light transmitting substrate and reflected at an interface between the photocathode and the vacuum space, so that the light is re-enter the photocathode. The light reflecting surface has an outwardly convex curved surface shape. The light incident surface is located inward of an imaginary spherical surface that is along the light reflecting surface.
Abstract:
A photocathode 4 includes an optically transparent conductive layer provided between a translucent substrate and a photoelectric conversion layer. The optically transparent conductive layer is formed of a constituent material including carbon. A Raman spectrum of the constituent material has a peak of a band, a peak of a band, a peak of a band, and a peak of a band.