Reflector design for a slab laser

Claim 1

A method for determining a shape of reflector in a slab laser including a solid-state lasing medium having as generally rectangular shape with two opposing major face surfaces, said slab laser including a first and a second optical pumping lamp respectively disposed adjacent said lasing medium face surfaces for impinging electromagnetic radiation thereon and further including cooling means for flowing a fluid coolant across at least a portion of said lasing medium, said lasing medium exhibiting a negative focal power lens effect in lateral edge portions thereof, said reflector being positioned to generally direct the electromagnetic radiation form said first and second pumping lamps onto said lasing medium face surfaces and having a shape effective to introduce a positive focal power lens effect approximately equal in magnitude to said negative focal power lens effect into a central portion of said lasing medium between said lasing medium lateral edge portions, the last recited positive and negative lens effects representing desired lens effect distribution across a width dimension of said lasing medium, said method comprising the steps of: (a) computing amounts of pumping energy absorbed in said lasing medium, as a function of width position, effective to produce a temperature distribution in said lasing medium which in turn produces said desired lens effect distribution, the amounts of absorbed pumping energy so computed corresponding to a desired pumping profile; (b) assigning a predetermined initial set of values to a predetermined set of reflector dimensional parameters descriptive of the shape of said reflector, said initial values defining a current reflector shape; (c) computing by ray tracing, based on the current reflector shape, a computed pumping profile corresponding to amounts of pumping energy absorbed in said lasing medium as a function of width position; (d) computing a value of a predetermined error function that expresses a deviation of said computed pumping profile from said desired pumping profile; (e) comparing the value of said error function computed in step (d) with a predetermined minimum value of said error function which represents an acceptable correspondence between said computed and desired pumping profiles and if said computed value is greater than the predetermined minimum value of said error function proceeding to step (f) and, if not, to step (g); (f) updating the values assigned to said reflector dimensional parameters in accordance with a numerical minimization technique to minimize said error function and repeating steps (c) through (e) with the updated reflector dimensional parameters defining the current reflector shape; and (g) stopping the method since the computed pumping profile resulting from the current reflector shape is sufficiently similar to said desired pumping profile that said desired lens effect distribution is substantially produced.

Claim 2

A method for determining a shape of reflector in a slab laser including a solid-state lasing medium having as generally rectangular shape with two opposing major face surfaces, said slab laser including a first and a second optical pumping lamp respectively disposed adjacent said lasing medium face surfaces for impinging electromagnetic radiation thereon and further including cooling means for flowing a fluid coolant across at least a portion of said lasing medium, said lasing medium exhibiting a negative focal power lens effect in lateral edge portions thereof, said reflector being positioned to generally direct the electromagnetic radiation form said first and second pumping lamps onto said lasing medium face surfaces and having a shape effective to introduce a positive focal power lens effect approximately equal in magnitude to said negative focal power lens effect into a central portion of said lasing medium between said lasing medium lateral edge portions, the last recited positive and negative lens effects representing desired lens effect distribution across a width dimension of said lasing medium, said method comprising the steps of: (a) computing amounts of pumping energy absorbed in said lasing medium, as a function of width position, effective to produce a temperature distribution in said lasing medium which in turn produces said desired lens effect distribution, the amounts of absorbed pumping energy so computed corresponding to a desired pumping profile; (b) assigning a predetermined initial set of values to a predetermined set of reflector dimensional parameters descriptive of the shape of said reflector, said initial values defining a current reflector shape; (c) computing by ray tracing, based on the current reflector shape, a computed pumping profile corresponding to amounts of pumping energy absorbed in said lasing medium as a function of width position; (d) computing a value of a predetermined error function that expresses a deviation of said computed pumping profile from said desired pumping profile; (e) comparing the value of said error function computed in step (d) with a predetermined minimum value of said error function which represents an acceptable correspondence between said computed and desired pumping profiles and if said computed value is greater than the predetermined minimum value of said error function proceeding to step (f) and, if not, to step (g); (f) updating the values assigned to said reflector dimensional parameters in accordance with a numerical minimization technique to minimize said error function and repeating steps (c) through (e) with the updated reflector dimensional parameters defining the current reflector shape; and (g) stopping the method since the computed pumping profile resulting from the current reflector shape is sufficiently similar to said desired pumping profile that said desired lens effect distribution is substantially produced.