Abstract: A very low amplitude interferometer suitable for detecting gravitational waves is disclosed. The interferometer has an optical cavity consisting of a glass plate sandwiched between two three-dimensional interferometric arrays and contacting a body in which micro-vibration is to be sensed. The interface between the interferometric arrays and the glass plate entraps thin layers of air. A coherent light source is used to illuminate one of the interferometric arrays. Micro-vibrations transmitted through the glass plate will affect the air layers sufficiently to render these vibrations detectable through interference patterns created by the reflected coherent light on a display screen.

Abstract: The invention relates to an ultrarapid camera for visualizing the intensity profile of a laser pulse. This camera comprises in vacuum housing a photocathode, an extraction grid, focalization electrodes, deflection plates and a visualization screen. According to the invention, the electron emitting photocathode is constituted by at least one metal tip (3, 12) and means (9, 10) are provided to send said laser pulse (13) into a zone situated in front of said tip.