High power laser employing fiber optic delivery means

Claim 1

A high power, pulsed solid state laser apparatus comprising, in combination: (a) a low gain tunable laser medium; (b) means for exciting said laser medium to emit coherent radiation at a fundamental wavelength; (c) reflecting means associated with said laser medium defining a resonant laser cavity for supporting coherent oscillation within said laser medium, said reflecting means comprising at least one output coupling means; (d) means for narrowing the frequency distribution of the coherent radiation emitted by the excited laser medium; (e) non-linear frequency conversion means within said resonant laser cavity, for transforming a portion of the coherent oscillation generated and supported within said laser cavity from its fundamental wavelength to a frequency-shifted derivative thereof, to generate a mixed wavelength laser beam; (f) fiber optic means for delivering said mixed wavelength laser beam to a point of use; and (g) means associated with said output coupling means for coupling said mixed wavelength laser beam generated within said resonant laser cavity into said fiber optic means; wherein said output coupling means has a higher degree of reflectivity for said fundamental wavelength than for said frequency-shifted wavelength, so that the frequency-shifted wavelength is preferentially emitted from said resonant laser cavity, whereby, in operation, the spatial and temporal build-up of regions of high intensity of said fundamental wavelength is minimized.

Claim 4

The apparatus of claims 1 or 2, further comprising a Q-switch within said resonant laser cavity.

Claim 5

The apparatus of claims 1 or 2, wherein said non-linear frequency conversion means is a second harmonic generating crystal.

Claim 6

The apparatus of claims 1 or 2, further comprising temperature control means for the means for narrowing the frequency distribution and the non-linear frequency conversion means.

Claim 10

The apparatus of claims 6 or 7, further comprising a Q-switch within said resonant laser cavity.

Claim 11

The apparatus of claims 6 or 7, wherein said non-linear frequency conversion means is a second harmonic generating crystal.

Claim 12

The apparatus of claims 6 or 7, further comprising temperature control means for the means for narrowing the frequency distribution and the second harmonic generating crystal.

Claim 13

The apparatus of claims 6 or 7, wherein said non-linear frequency conversion means is a second harmonic generating crystal, and wherein one of said reflecting means is a highly reflecting focussing mirror which is arranged to focus the fundamental frequency into said second harmonic generating crystal.

Claim 14

A method for generating pulsed laser radiation of a fundamental wavelength and a frequency-shifted derivative thereof, and delivering at least the fundamental wavelength radiation to a point of use, while minimizing spatial and temporal build-up of regions of high intensity of the fundamental wavelength, which comprises, in combination: (a) generating pulsed, coherent oscillations of a frequency-narrowed fundamental wavelength within a resonant laser cavity by exciting a low gain tunable laser medium located within said laser cavity and subjecting said oscillations to means for narrowing frequency distribution; (b) subjecting said coherent oscillations of frequency-narrowed fundamental wavelength within said resonant laser cavity to the action of non-linear frequency conversion means, to preferentially frequency-shift peak power portions of said fundamental wavelength; (c) preferentially extracting the frequency-shifted portion of said coherent oscillations from said resonant laser cavity, while maintaining oscillation at said fundamental frequency, and (d) coupling at least the fundamental frequency portion of said coherent oscillations into fiber optic beam delivery means, for delivery to a point of use.

Claim 15

A method for generating pulsed laser radiation of a fundamental wavelength and a frequency-shifted derivative thereof, and delivering at least the fundamental wavelength radiation to a point of use, while minimizing spatial and temporal build-up of regions of high intensity of the fundamental wavelength, which comprises, in combination: (a) generating pulsed, coherent oscillations of a frequency-narrowed fundamental wavelength within a resonant laser cavity by exciting a low gain tunable laser medium located within said laser cavity and subjecting said oscillations to means for narrowing frequency distribution; (b) subjecting said coherent oscillations of frequency-narrowed fundamental wavelength within said resonant laser cavity to the action of non-linear frequency conversion means, to preferentially frequency-shift peak power portions of said fundamental wavelength; (c) preferentially extracting the frequency-shifted portion of said coherent oscillations from said resonant laser cavity, while maintaining oscillation at said fundamental frequency, and (d) coupling at least the fundamental frequency portion of said coherent oscillations into fiber optic beam delivery means, for delivery to a point of use.