Abstract: An optical amplifier comprises a gain medium having an input surface and an output surface wherein the output surface is larger than the input surface. The gain medium may be frustum shaped. The optical amplifier includes a negative diverging lens to receive an extraction laser beam and to cause the laser beam to expand as the beam passes through the gain medium. The amplifier further comprises a positive collimating lens configured to receive the expanding amplified beam and reduce the divergence. The gain medium can be pumped by counter-propagating radiation. The fluence of the laser beam within the gain medium is configured to be near constant along the length of the gain medium and may be within 1.5-2.0 FSAT. The gain medium may be doped with dopant to provide gain, with larger concentration of dopants proximal the input surface and smaller concentration proximal the output surface.

Abstract: The present disclosure relates to a waveplate having a substrate forming an optic. The substrate may have an integral portion forming a plurality of angled columnar features on an exposed surface thereof. The plurality of angled columnar features may further be aligned parallel with a directional plane formed non-parallel to a reference plane, with the reference plane being normal to a surface of the substrate. The metasurface forms a birefringent metasurface.

Abstract: Technology is provided to transform spatially variable arbitrary polarization states and wavefront of a high-fluence, large-aperture laser beam to prescribed spatially resolved polarization states and wavefront at a specific position, with minimal losses. Technology is also provided to transform spatially resolved polarization states and wavefront at a specific position to spatially variable arbitrary polarization states and wavefront.

Abstract: The present disclosure relates to a waveplate having a substrate forming an optic. The substrate may have an integral portion forming a plurality of angled columnar features on an exposed surface thereof. The plurality of angled columnar features may further be aligned parallel with a directional plane formed non-parallel to a reference plane, with the reference plane being normal to a surface of the substrate. The metasurface forms a birefringent metasurface.