Optical cavity for a laser

Claim 2

A laser with a single critical surface Brewster window, comprising: a laser cavity having a principal optical axis along which is propagated the laser beam; a Littrow prism having a first planar face located on said principal optical axis, oriented at Brewster''s angle with respect thereto, and mounted as a windown in contact with said laser cavity, for admitting a refracted, plane polarized component of said laser beam incident along said principal axis; said Littrow prism having a second substantially planar face which intersects said first face along a line perpendicular to said principal axis, at an angle with respect to said first face such that said second face is substantially perpendicular to said refracted component of said laser beam; a reflecting means in contact with said second face and normal to the direction of propagation of said refracted, plane polarized component for reflecting said component back upon itself and out of said first planar face of said prism along said principal axis; whereby laser action is sustained generating a polarized laser beam, with a Brewster window having only one critical surface.

Claim 3

The laser with a single critical surface Brewster window of claim 1, where said reflecting means comprises: a planar mirror mounted on said second face of said Littrow prism, and perpendicular to the direction of propagation of said refracted, plane polarized component; said planar mirror mounted by means of a layer of optical cement having an index of refraction matching that of said Littrow prism.

Claim 4

The laser with a single critical surface Brewster window of claim 1, wherein said reflecting means comprises: a 4590* triangular prism, mounted with its hypotenuse on said second face of said Littrow prism, and perpendicular to the direction of propagation of said refracted, plane polarized component; said 4590* triangular prism mounted by means of a layer of optical cement having an index of refraction matching that of said Littrow prism; and wherein said laser cavity comprises: a folded tube having paralled optical axes spaced so that light transmitted from a first segment of said tube, is totally internally reflected in said 4590* prism so as to be transmitted through a second portion of said Littrow prism, exiting from the Littrow prism at a point coincident with the axis of propagation of light in said second segment of said laser tube.

Claim 5

A folded path gaseous discharge laser having a maximized optical efficiency and a maximized optical power output, comprising: a first cylindrical lasing cavity tube with a first anode therein, for supporting laser action in a discharge excited gas along a first gaseous discharge path contained therein; a second cylindrical lasing cavity tube parallel to and juxtaposed side-by-side with said first tube, with a second anode therein for supporting laser action in a discharge excited gas along a second gaseous discharge path contained therein; a cylindrical mounting tube encompassing and sealed to said first and second lasing cavity tube with its axis parallel to the axes of said first and second lasing cavity tubes, and forming a fourth gaseous discharge path In the region bounded by said mounting tube and said first and second lasing cavity tube; means mounted on a first end of said mounting tube and spaced from the proximate first end of said first and said second lasing cavity tube, for reflecting laser light generated along the axis of said first lasing cavity tube so as to enter said second lasing cavity tube along its axis and for reflecting laser light generated along the axis of said second lasing cavity tube so as to enter said first lasing cavity tube along its axis; the region separating said reflecting means from said first end of said first and second lasing cavity tubes and encompassed by said mounting tube, forming a third gaseous discharge conduction path; a flat mirror mounted on a second end of said second lasing cavity tube, opposite the end where is located said reflecting means; a spherical mirror mounted on a second end of said first lasing cavity tube, opposite the end where is located said reflecting means; said spherical mirror having a center curvature focused upon the surface of said flat mirror, along a path connecting said spherical mirror to said reflecting means and connecting said reflecting means to said flat mirror; said second lasing cavity tube having a diameter less than the diameter of said first lasing cavity tube so as to minimize the volume of gaseous discharge not contributing to laser action in said second lasing cavity tube, to maximize the optical efficiency thereof; a cylindrical reservoir tube encompassing and sealed to said cyclindrical mounting tube, with a cathode therein, for serving as a reservoir for the gaseous discharge and forming a fifth gaseous discharge path; said mounting tube having a discharge port communicating between the reservoir tube containing said fifth gaseous discharge path and the mounting tube containing said fourth gaseous discharge path; the series array of said first, third, fourth and fifth gaseous discharge paths conducting a higher gaseous discharge current from said first anode than the gaseous discharge current from said second anode connected through the series array of said second, third, fourth and fifth gaseous discharge paths, such that the gaseous discharge current density in said first lasing cavity tube is substantially equal to the gaseous discharge current density in said second lasing cavity tube, maximizing the optical power output of the system.

Claim 6

A folded path gaseous discharge laser having a maximized optical efficiency and a maximized optical power output, comprising: a first cylindrical lasing cavity tube with a first anode therein, for supporting laser action in a discharge excited gas along a first gaseous discharge path contained therein; a second cylindrical lasing cavity tube parallel to and juxtaposed side-by-side with said first tube, with a second anode therein for supporting laser action in a discharge excited gas along a second gaseous discharge path contained therein; a cylindrical mounting tube encompassing and sealed to said first and second lasing cavity tube with its axis parallel to the axes of said first and second lasing cavity tubes, and forming a fourth gaseous discharge path In the region bounded by said mounting tube and said first and second lasing cavity tube; means mounted on a first end of said mounting tube and spaced from the proximate first end of said first and said second lasing cavity tube, for reflecting laser light generated along the axis of said first lasing cavity tube so as to enter said second lasing cavity tube along its axis and for reflecting laser light generated along the axis of said second lasing cavity tube so as to enter said first lasing cavity tube along its axis; the region separating said reflecting means from said first end of said first and second lasing cavity tubes and encompassed by said mounting tube, forming a third gaseous discharge conduction path; a flat mirror mounted on a second end of said second lasing cavity tube, opposite the end where is located said reflecting means; a spherical mirror mounted on a second end of said first lasing cavity tube, opposite the end where is located said reflecting means; said spherical mirror having a center curvature focused upon the surface of said flat mirror, along a path connecting said spherical mirror to said reflecting means and connecting said reflecting means to said flat mirror; said second lasing cavity tube having a diameter less than the diameter of said first lasing cavity tube so as to minimize the volume of gaseous discharge not contributing to laser action in said second lasing cavity tube, to maximize the optical efficiency thereof; a cylindrical reservoir tube encompassing and sealed to said cyclindrical mounting tube, with a cathode therein, for serving as a reservoir for the gaseous discharge and forming a fifth gaseous discharge path; said mounting tube having a discharge port communicating between the reservoir tube containing said fifth gaseous discharge path and the mounting tube containing said fourth gaseous discharge path; the series array of said first, third, fourth and fifth gaseous discharge paths conducting a higher gaseous discharge current from said first anode than the gaseous discharge current from said second anode connected through the series array of said second, third, fourth and fifth gaseous discharge paths, such that the gaseous discharge current density in said first lasing cavity tube is substantially equal to the gaseous discharge current density in said second lasing cavity tube, maximizing the optical power output of the system.

Claim 7

The folded path gaseous discharge laser of claim 4, wherein the reflecting means further comprises: a Littrow prism having a first planar face located on the axes of said first and second cylindrical lasing cavity tube and oriented at Brewster''s angle with respect thereto, for admitting a refracted, plane polarized component of the laser beam formed by said first cyclindrical lasing cavity; said Littrow prism having a second substantially planar face which intersects said first face along a line perpendicular to the plane formed by the axes of said first and second cylindrical lasing cavity tubes at an angle with respect to said first face such that said second face is substantially perpendicular to said refracted component of said laser beam; a 4590* triangular prism mounted with its hypotenuse of said second face of said Littrow prism, and perpendicular to the direction of propagation of said refracted, plane polarized component, and disposed to transmit from said first cyclindrical lasing cavity tube, the laser beam generated therein, which is totally internally reflected in said 4590* prism so as to be transmitted through a second portion of said Littrow prism, exiting from the Littrow prism at a point coincident with the axis of said second cylindrical lasing cavity tube; said 4590* prism mounted by means of a layer of optical cement having an index of refraction matching that of said Littrow prism.