Wavelength beam combining laser systems with high beam quality factor
In various embodiments, optical repositioners and/or angled dispersive elements are utilized to manipulate portions of an input laser beam emitted by a group of laser emitters in order to form a multi-wavelength output beam having a high beam quality factor.
1. A laser apparatus comprising:
a plurality of laser emitters arranged in an array and each emitting a laser beam at a different wavelength, the plurality of laser beams collectively forming an array having first and second orthogonal dimensions;
focusing optics for receiving the plurality of laser beams and combining the plurality of laser beams along the first dimension to form a combined beam;
a plurality of dispersive elements positioned to receive the combined beam and transmit a multi-wavelength beam, each dispersive element (i) being disposed at a different angle with respect to the combined beam, and (ii) transmitting a band of the multi-wavelength beam being composed of a different set of wavelengths;
a partially reflective output coupler positioned to receive the multi-wavelength beam, transmit a portion of the multi-wavelength beam therethrough, and reflect a second portion of the multi-wavelength beam back toward the plurality of dispersive elements; and
a plurality of dichroic elements positioned to (i) receive the portion of the multi-wavelength beam transmitted by the partially reflective output coupler, (ii) separate the portion of the multi-wavelength beam into the plurality of bands, and (iii) spatially overlap the separated bands into a final overlapped beam.
2. The laser apparatus of claim 1 , wherein each dispersive element comprises a diffraction grating.
3. The laser apparatus of claim 1 , wherein the focusing optics comprises at least one of a cylindrical lens or a cylindrical mirror.
4. The laser apparatus of claim 1 , wherein each dichroic element comprises a dichroic mirror, a dichroic filter, or an interference filter.
5. The laser apparatus of claim 1 , wherein the plurality of dispersive elements are aligned along a beam-combining line of the combined beam.
6. The laser apparatus of claim 1 , wherein the array is a one-dimensional array.
7. The laser apparatus of claim 1 , wherein the array is a two-dimensional array.
8. The laser apparatus of claim 1 , wherein each dispersive element comprises a dispersive prism, a grism, or an Eschelle grating.
9. The laser apparatus of claim 1 , further comprising a workpiece to which the final overlapped beam is transmitted.
10. The laser apparatus of claim 1 , further comprising an optical fiber to which the final overlapped beam is transmitted.
11. The laser apparatus of claim 1 , wherein the output coupler is positioned to reflect the second portion of the multi-wavelength beam back toward the plurality of dispersive elements and thence to the plurality of laser emitters, whereby an external lasing cavity is formed.
12. The laser apparatus of claim 1 , wherein a size of the final overlapped beam is equal to a size of one of the bands.
13. The laser apparatus of claim 1 , wherein the plurality of dispersive elements comprises at least three dispersive elements.