Abstract A field-emission cathode having a multitude of field emission points for emitting a copious stream of electrons when subjected to a high field. The cathode is constructed by compressing a multitude of tungsten strips alternately arranged with molybdenum strips and copper ribbons or compressing alternately arranged copper plated tungsten and molybdenum strips, heating the arrangement to braze the tungsten and molybdenum strips together with the copper, machining and grinding the exposed strip edges of one side of the brazed arrangement to obtain a precisely planar surface, etching a portion of the molybdenum and copper to leave the edges of the tungsten strips protruding for electron emission, and subjecting the protruding edges of the tungsten strips to a high electric field to degas and roughen the surface to provide a large number of emitting points. The resulting structure is particularly useful as a cathode in a transversely excited gaseous laser where the cathode is mounted in a vacuum chamber for emitting electrons under the influence of a high electric field between the cathode and an extractor grid. The electrons pass through the extractor grid, a thin window in the wall of the laser chamber and into the laser chamber which is filled with a gaseous mixture of helium, nitrogen and carbon dioxide. A second grid is mounted on the gaseous side of the window. The electrons pass into the laser chamber under the influence of a second electric field between the second grid and an anode in the laser chamber to raise selected gas atoms of the gaseous mixture to appropriately excited states so that a subsequent coherent light beam passing through the mixture transversely to the electron stream through windows in opposite ends of the laser chamber stimulates the excited atoms to amplify the beam.
A high-emission cold cathode in combination with a transversely excited gaseous laser, including: a first multitude of electrically conducting strips of a first material; a second multitude of electrically conducting strips of a second material brazed to said first strips and alternately arranged with said first strips to space them apart, the edges of said first strips protruding from said second strips on one side of said cathode, the edges of said protruding strips being coplanar; an elongated chamber filled with a laser gas; an anode electrode mounted within said chamber; a window in the wall of said chamber opposite said anode, said window being pervious to the passage of electrons therethrough; and a vacuum chamber mounted adjacent said gas filled chamber at said window, said cathode being mounted within said vacuum chamber for emitting electrons to pass through said window into the gas-filled chamber for exciting the gas to a higher energy level for subsequent amplification of a coherent beam of radiation passing through said gas-filled chamber.
Claim 2
Dependent Claim
168 words
A high-emission cold cathode in combination with a transversely excited gaseous laser, including: a first multitude of electrically conducting strips of a first material; a second multitude of electrically conducting strips of a second material brazed to said first strips and alternately arranged with said first strips to space them apart, the edges of said first strips protruding from said second strips on one side of said cathode, the edges of said protruding strips being coplanar; an elongated chamber filled with a laser gas; an anode electrode mounted within said chamber; a window in the wall of said chamber opposite said anode, said window being pervious to the passage of electrons therethrough; and a vacuum chamber mounted adjacent said gas filled chamber at said window, said cathode being mounted within said vacuum chamber for emitting electrons to pass through said window into the gas-filled chamber for exciting the gas to a higher energy level for subsequent amplification of a coherent beam of radiation passing through said gas-filled chamber.
Claim 3
Dependent Claim
52 words
The combination of claim 1, further including an extractor grid mounted within said vacuum chamber between said cathode and said window, said grid being mounted precisely parallel to a plane defined by the edges of said protruding strips, and means for sustaining a high electric field between said grid and said cathode.
Claim 4
Dependent Claim
30 words
The cathode of claim 1, wherein said first strips are tungsten, said second strips are molybdenum, and said first and second strips are brazed together with copper between the strips.