Superfluorescent laser with improved beam divergence and spacial brightness

Claim 2

In a pulsed superfluorescent laser device having short pulse output pulses of light energy, the combination comprising: a. means defining an elongated unstable optically resonant cavity having a longitudinal axis and a predetermined length; b. means for supplying to said cavity a gaseous lasing medium having at least two energy levels above the ground energy level in which the net excitation rate for the higher of the two upper levels is greater than the net excitation rate for the lower of the two energy levels by an amount sufficient to provide superfluorescence during electric discharge in said medium; c. first and second oppositely disposed electrode means communicating with said cavity for applying an electric field across said cavity normal to and along said longitudinal axis; and d. pulse circuit means coupled to said electrode means and adapted to be coupled to a pulsed source of high voltage electrical power for sequentially providing discrete pulses of said electric field in said cavity and sequentially providing discrete superfluorescent inversions between the said two energy levels of said gas, said inversions having a pulse width that is short compared to the transit time of light for several said cavity lengths.

Claim 3

A laser device as defined in claim 1 wherein said means defining said cavity comprises a pair of oppositely disposed mirrors and means defining a working region for receiving said gas intermediate said mirrors.

Claim 4

A laser device as defined in claim 2 wherein said mirrors are disposed exterior of said means defining said working region.

Claim 5

A laser device as deFined in claim 3 wherein said means defining said working region includes two oppositely disposed windows transparent to light at the wavelength of radiation produced in said working region, said mirrors being disposed adjacent said windows and in optical alignment.

Claim 6

A laser device as defined in claim 2 wherein said gas is nitrogen and said pulse width is about 40 nanoseconds.

Claim 7

A laser device as defined in claim 2 wherein said gas is neon and said pulse width is about 10 nanoseconds.

Claim 8

A laser device as defined in claim 1 wherein said gas is nitrogen and said means defining said unstable resonant cavity includes a concave cylindrical mirror and a convex cylindrical feedback mirror.

Claim 9

A laser device as defined in claim 7 wherein said cavity has a length L and the sum of the radii of said convex and concave mirrors equals about 2L.

Claim 10

A laser device as defined in claim 8 wherein said means defining said cavity includes a window transparent to light at the wavelength of radiation produced in said cavity, said feedback mirror being disposed adjacent said window and arranged and adapted to reflect back to said concave mirror only a small portion of the light energy reflected from said concave mirror, the remainder being emitted from said cavity through said window as said output pulses.

Claim 11

In a pulsed superfluorescent laser device having self-terminating short pulse output pulses in the range of about 10 to 40 nanoseconds, the combination comprising: a. means defining an elongated unstable optically resonant cavity having a longitudinal axis, a predetermined length, and a substantially rectangular cross section defined by a width dimension substantially less than a height dimension, said means comprising a first mirror having a substantially fully reflective concave reflective surface having a predetermined radius and a second mirror having a substantially fully reflective convex feedback surface having a radius substantially less than the radius of said concave surface, said mirrors each having a longitudinal axis normal to said height dimension and normal to and coincident with said cavity longitudinal axis, said means further including a window transparent to light at the wavelength of radiation produced in said cavity, said feedback surface being disposed adjacent said window and said concave surface being disposed at the opposite end of said cavity; b. a lasing medium taken from the class consisting of nitrogen and neon; c. first and second oppositely disposed electrode means communicating with said cavity for applying an electric field across said cavity normal to and along said longitudinal axis; and d. pulse circuit means coupled to said electrode means and adapted to be coupled to a pulsed source of high voltage electrical power for sequentially providing said electric field in said cavity and sequentially providing discrete superfluorescent inversion between the two energy levels of said gas, said inversions having a pulse width that is short compared to the transit time of light for several said cavity lengths.

Claim 12

In a pulsed superfluorescent laser device having self-terminating short pulse output pulses in the range of about 10 to 40 nanoseconds, the combination comprising: a. means defining an elongated unstable optically resonant cavity having a longitudinal axis, a predetermined length, and a substantially rectangular cross section defined by a width dimension substantially less than a height dimension, said means comprising a first mirror having a substantially fully reflective concave reflective surface having a predetermined radius and a second mirror having a substantially fully reflective convex feedback surface having a radius substantially less than the radius of said concave surface, said mirrors each having a longitudinal axis normal to said height dimension and normal to and coincident with said cavity longitudinal axis, said means further including a window transparent to light at the wavelength of radiation produced in said cavity, said feedback surface being disposed adjacent said window and said concave surface being disposed at the opposite end of said cavity; b. a lasing medium taken from the class consisting of nitrogen and neon; c. first and second oppositely disposed electrode means communicating with said cavity for applying an electric field across said cavity normal to and along said longitudinal axis; and d. pulse circuit means coupled to said electrode means and adapted to be coupled to a pulsed source of high voltage electrical power for sequentially providing said electric field in said cavity and sequentially providing discrete superfluorescent inversion between the two energy levels of said gas, said inversions having a pulse width that is short compared to the transit time of light for several said cavity lengths.

Claim 13

A laser device as defined in claim 10 wherein said concave surface and said convex feedback surfaces are cylindrical in shape.

Claim 14

A laser device as defined in claim 10 wherein said concave surface and said convex feedback surfaces are spherical in shape.

Claim 15

A laser device as defined in claim 12 wherein said feedback surface is disposed on a transparent supporting member.