Aerodynamic laser window

Claim 2

In a gaseous laser system comprising a cavity containing an active gaseous medium capable of being excited to provide stimulated emission of radiation and additionally including means defining an optical cavity and exciting means for exciting said gaseous medium to provide in said optical cavity said stimulated emission of radiation, aerodynamic window apparatus comprising: a. means defining a first laser beam aperture for providing optical communication between the environment exterior of said cavity and stimulated emission of radiation produced in said cavity; b. enclosure means sealably surrounding and extending outwardly from said first laser beam aperture, said enclosure means having a gas port and having a second laser beam aperture spaced from and in optical alignment with said first laser beam aperture, said gas port being arranged and adapted to be coupled to means for providing a gas flow through said gas port and the interior of said enclosure means intermediate said first and second laser beam apertures at subsonic velocity; c. a plurality of vane members having centrally disposed apertures, said vane members being spaced one from another and disposed within said enclosure means intermediate said first and second laser beam apertures, said vane member apertures being in optical alignment with said first and second laser beam apertures and the portion of said vane members surrounding said apertures having a substantially aerodynamic configuration substantially effective to intercept a gaseous jet formed at one of said laser beam apertures and dissipate said jet prior to its reaching the other of said laser beam apertures, the portions of the interior of said enclosure intermediate said vane members each being in communication with said gas port; and d. optical means in optical communication with stimulated emission of radiation in said cavity and with the environment exterior of said cavity through said laser beam apertures, said optical means having a focal region having a finite depth of field located within said enclosure, said vane members being located within said depth of field.

Claim 3

The combination as defined in claim 1 wherein said first laser beam aperture is of a size and located with respect to said focal region to provide minimum flow of gas there through.

Claim 4

The combination as defined in claim 1 and additionally including: a. first gas pumping means for maintaining the pressure in said cavity at a value less than atmospheric; and b. second gas pumping means coupled to said gas port for providing said gas flow through said enclosure means having a pressure at said first laser beam aperture only slightly different from that in said cavity, and said first laser beam aperture is of a size and located with respect to said focal region to provide for the pressure in said enclosure a predetermined flow of gas through said first laser beam aperture.

Claim 5

The combination as defined in claim 3 wherein the inner surface of said enclosure means intermediate said first and second laser beam apertures is cylindrical, said gas port is coupled to a pressurized gas source, and said gas is introduced tangentially into said enclosure means to produce a vortex.

Claim 6

The combination as defined in claim 1 wherein the size of said second laser beam aperture is less than the size of said first laser beam aperture.

Claim 7

The combination as defined in claim 5 and additionally including: a. exhaust pump means coupled to said gas port for exhausting gas from said enclosure.

Claim 8

The combination as defined in claim 6 wherein said exhaust pump means is adapted to maintain in said enclosure at said first laser beam aperture a pressure less than that in said cavity and said laser beam apertures and said vane member apertures are of a size to provide for the pressUre in said enclosure a substantially minimum flow of gas from said cavity and into said enclosure.

Claim 9

In a gaseous laser system where an active medium comprising a gas capable of being excited to provide stimulated emission of radiation flows through means defining a cavity at subatmospheric pressure and including reflector means in said cavity for forming a laser beam, aerodynamic window apparatus for coupling at least a portion of said laser beam out of said cavity comprising: a. means defining a first laser beam aperture forming an exit for said laser beam; b. enclosure means sealably surrounding and extending outwardly from said first laser beam aperture, said enclosure means having a gas port and having a second laser beam aperture spaced from and in optical alignment with said first laser beam aperture, said gas port being arranged and adapted to be coupled to means for providing a gas flow through said gas port and the interior of said enclosure means intermediate said first and second laser beam apertures at subsonic velocity; c. a plurality of vane members having centrally disposed apertures, said vane members being spaced one from another and disposed within said enclosure means intermediate said first and second laser beam apertures, said vane member apertures being in optical alignment with said first and second laser beam apertures and the portion of said vane members surrounding said apertures gradually curving toward said second laser beam aperture to define a substantially aerodynamic configuration substantially effective to intercept a gaseous jet formed at said second laser beam aperture and dissipate said jet prior to its reaching said first laser beam aperture, the portions of the interior of said enclosure intermediate said vane members each being at least substantially in communication with said gas port; and d. optical means for receiving and directing a portion of said laser beam out of said cavity through said enclosure means via said first and second laser beam apertures and said vane member apertures, said optical means focusing said directed beam to a focal region having a finite depth of field located within said enclosure, said vane members being located within said depth of field.

Claim 10

In a gaseous laser system where an active medium comprising a gas capable of being excited to provide stimulated emission of radiation flows through means defining a cavity at subatmospheric pressure and including reflector means in said cavity for forming a laser beam, aerodynamic window apparatus for coupling at least a portion of said laser beam out of said cavity comprising: a. means defining a first laser beam aperture forming an exit for said laser beam; b. enclosure means sealably surrounding and extending outwardly from said first laser beam aperture, said enclosure means having a gas port and having a second laser beam aperture spaced from and in optical alignment with said first laser beam aperture, said gas port being arranged and adapted to be coupled to means for providing a gas flow through said gas port and the interior of said enclosure means intermediate said first and second laser beam apertures at subsonic velocity; c. a plurality of vane members having centrally disposed apertures, said vane members being spaced one from another and disposed within said enclosure means intermediate said first and second laser beam apertures, said vane member apertures being in optical alignment with said first and second laser beam apertures and the portion of said vane members surrounding said apertures gradually curving toward said second laser beam aperture to define a substantially aerodynamic configuration substantially effective to intercept a gaseous jet formed at said second laser beam aperture and dissipate said jet prior to its reaching said first laser beam aperture, the portions of the interior of said enclosure intermediate said vane members each being at least substantially in communication with said gas port; and d. optical means for receiving and directing a portion of said laser beam out of said cavity through said enclosure means via said first and second laser beam apertures and said vane member apertures, said optical means focusing said directed beam to a focal region having a finite depth of field located within said enclosure, said vane members being located within said depth of field.

Claim 11

The combination as defined in claim 8 wherein the surface delineating said first laser beam aperture is at least in part generally conical in shape and decreases in diameter in the direction of said directed beam.

Claim 12

The combination as defined in claim 8 wherein the surfaces of said means defining said first laser beam aperture are disposed at an angle to the longitudinal axis of said directed beam whereby radiation reflected therefrom is reflected at an angle to the longitudinal axis of said directed beam sufficient to at least substantially prevent the development of spurious modes in said directed beam.

Claim 13

The combination as defined in claim 8 wherein the surface delineating said first laser beam aperture is disposed and arranged to reflect radiation incident thereon into said enclosure.

Claim 14

The combination as defined in claim 8 and additionally including: a. first gas pumping means for maintaining the pressure in said cavity at a value less than atmospheric; and b. second gas pumping means coupled to said gas port for providing said gas flow through said enclosure means having a pressure at said first laser beam aperture only slightly different from that in said cavity, and said laser beam apertures and said vane member apertures are of a size and located with respect to said focal region to provide for the pressure within said enclosure a predetermined flow of gas through said first laser beam aperture.

Claim 15

The combination as defined in claim 12 wherein the pressure in said enclosure means is greater than that in the cavity whereby said predetermined gas flow is from said enclosure means into said cavity.

Claim 16

The combination as defined in claim 13 and additionally including valve means for selectivelY preventing the flow of gas between said cavity and said enclosure means.

Claim 17

The combination as defined in claim 8 wherein the inner surface of said enclosure means intermediate said first and second laser beam apertures is cylindrical, said gas port is coupled to a pressurized gas source, and said gas is introduced tangentially into said enclosure means to produce a vortex.

Claim 18

The combination as defined in claim 12 wherein the pressure in said enclosure means at said first laser beam aperture is less than that in the cavity whereby said predetermined gas flow is from said cavity into said enclosure means.

Claim 19

The combination as defined in claim 16 wherein said second gas pumping means includes an exhaust pump for exhausting gas from said enclosure means.

Claim 20

The combination as defined in claim 17 and additionally including valve means for selectively preventing the flow of gas between said cavity and said enclosure means.

Claim 21

In the production of laser radiation, the steps of: a. flowing an active gaseous medium at less than atmospheric pressure through an optical cavity; b. exciting said medium to produce laser radiation in said cavity; c. directing a beam comprising at least a portion of said laser radiation out of said cavity and into the atmosphere through an enclosure including at least two adjacent first and second open laser beam apertures of a size not significantly greater than that of said beam passing therethrough; d. focusing said portion of said laser radiation to a focal region having a finite depth of field located within said enclosure; e. providing a subsonic gas flow intermediate said first and second apertures and out of said enclosure through a gas port producing a pressure there between that in combination with the size of said apertures provides a first predetermined flow of gas from said cavity through said first aperture and into said enclosure substantially less than a second flow of gas from the atmosphere into said enclosure as an expanding jet at said second aperture; and f. sequentially intercepting the peripheral portion of said expanding jet within said focal region depth of field to effectively dissipate said jet before it reaches said first aperture.

Claim 22

In the production of laser radiation, the steps of: a. flowing an active gaseous medium at less than atmospheric pressure through an optical cavity; b. exciting said medium to produce laser radiation in said cavity; c. directing a beam comprising at least a portion of said laser radiation out of said cavity and into the atmosphere through an enclosure including at least two adjacent first and second open laser beam apertures of a size not significantly greater than that of said beam passing therethrough; d. focusing said portion of said laser radiation to a focal region having a finite depth of field located within said enclosure; e. providing a subsonic gas flow intermediate said first and second apertures and out of said enclosure through a gas port producing a pressure there between that in combination with the size of said apertures provides a first predetermined flow of gas from said cavity through said first aperture and into said enclosure substantially less than a second flow of gas from the atmosphere into said enclosure as an expanding jet at said second aperture; and f. sequentially intercepting the peripheral portion of said expanding jet within said focal region depth of field to effectively dissipate said jet before it reaches said first aperture.