High intensity and high power solid state laser amplifying system and method
Systems and methods are provided for achieving high power and high intensity laser amplification. In a four-pass optical amplifying system, a linear polarized optical beam is directed by various optical elements four times through an optical amplifier. The optical amplifier is transversely pumped by a pumping energy source that includes laser diode arrays. The pumping module and the other optical components are provided to counteract thermal lensing effects, induced thermal birefringence effects and to achieve enhanced amplification and efficiencies.
1 . A pumping module for substantially uniformly pumping a laser crystal rod, the laser crystal rod having a longitudinal axis, comprising:
a set of laser diode arrays disposed around the laser crystal rod, the laser diode arrays being approximately equally spaced around the laser crystal rod, each of the laser diode arrays including laser diodes that are disposed in a plane that is substantially orthogonal to the longitudinal axis of the laser crystal rod, the laser diodes emitting light that substantially uniformly pumps the laser crystal rod.
2 . The pumping module according to claim 1 , wherein the set of laser diode arrays includes an odd number of laser diode arrays.
3 . The pumping module according to claim 1 , wherein the set of laser diode arrays includes at least five laser diode arrays.
4 . A pumping module according to claim 1 , further comprising:
a spherical lensing module disposed along the optical axis, the lensing module being adapted to approximately negate thermal spherical lensing effects present in the laser crystal rod during the substantially uniform pumping of the laser crystal rod.
5 . The pumping module according to claim 4 , wherein the spherical lensing module includes a negative lens.
6 . The pumping module according to claim 4 , wherein the spherical lensing module includes a positive lens.
7 . A pumping module according to claim 1 , further comprising:
a reflecting element disposed in the plane and opposite a respective laser diode array with respect to the laser crystal rod, the reflecting element reflecting, back to the laser crystal rod, light emitted from the respective laser diode array that passes through the laser crystal rod without contributing to the pumping of the laser diode.
8 . A pumping module according to claim 1 , further comprising:
at least one electrical load coupled to at least one laser diode array, wherein the electrical load is configured to match a power level of the at least one laser diode array to a power level of the laser diode array with a lowest power level in the set.
9 . A pumping module according to claim 1 , further comprising:
power control means coupled to at least one laser diode array, the power control means are configured to adjust light intensity of the at least one laser diode array to match a laser diode array with a lowest pumping light intensity.
10 . A pumping module according to claim 1 ,
wherein each laser diode has a light emitting surface that has a substantially rectangular shape characterized by a long side and a short side, each laser diode being disposed relative to the laser crystal rod such that the short side extends in a substantially parallel direction as the longitudinal axis of the laser crystal rod.
11 . A pumping module according to claim 1 , further comprising:
cylindrical lenses disposed between the laser diode arrays and the laser crystal rod, the cylindrical lenses being configured to guide the emitted light toward the laser crystal rod, the cylindrical lenses being adapted such that focal points of the lenses are not within the laser crystal rod.
12 . A pumping module according to claim 1 , further comprising:
cylindrical lenses disposed between the laser diode arrays and the laser crystal rod, the cylindrical lenses being configured to guide the emitted light toward the laser crystal rod, the cylindrical lenses being integrally formed with a cladding layer that is disposed around the laser crystal rod.