Abstract: A laser gain element including an undoped layer of a monoclinic double tungstate (MDT) crystal, and a method of forming a laser gain element are provided. The laser gain element includes a layer of doped MDT crystal adjacent to the undoped layer, the doped MDT layer including a pre-selected concentration of rare earth ions. The layer of doped MDT crystal has an absorption peak at a first wavelength and an emission peak at a second wavelength longer than the first wavelength; and the layer of doped MDT crystal has a fluorescence emission with a weighted average at a third wavelength shorter than the first wavelength. A laser resonator cavity formed with a plurality of composite gain elements as above is also provided.

Abstract: A laser gain element including an undoped layer of a monoclinic double tungstate (MDT) crystal, and a method of forming a laser gain element are provided. The laser gain element includes a layer of doped MDT crystal adjacent to the undoped layer, the doped MDT layer including a pre-selected concentration of rare earth ions. The layer of doped MDT crystal has an absorption peak at a first wavelength and an emission peak at a second wavelength longer than the first wavelength; and the layer of doped MDT crystal has a fluorescence emission with a weighted average at a third wavelength shorter than the first wavelength. A laser resonator cavity formed with a plurality of composite gain elements as above is also provided.

Abstract: A system and method for generating electrical power from a heat source utilizing both photonic and thermal conversion are disclosed. Specifically, power is generated by coupling photon converters to thermoelectric pairs in a way such that the thermoelectric pairs gain not only the charge carriers (holes and electrons) generated by the photons absorbed by the photon converters, but also the charge carriers generated by excess heat in the photon converters and an added thermal gradient generated by excess energy in the absorbed photons. Heat exchanger variations for such a system are also disclosed. Specifically, heat exchangers with and without photon emitters are disclosed and variants of refractive indices for heat exchanger systems are disclosed.

Abstract: Method of manufacturing a laser medium with a material having a surface and a dopant in the material distributed whereby the material has a spatially variant optical flux density profile uses tailored non-uniform gain profiles within a Yb:YAG laser component (rod, slab, disc, etc.) achieved by a spatial material modification in the spatially masked pre-forms. High temperature-assisted reduction leads to the coordinate-dependent gain profiles, which are controlled by the topology of the deposited solid masks. The gain profiles are obtained by reducing the charge state of the laser-active trivalent Yb3+ ions into inactive divalent Yb2+ ions. This valence conversion process is driven by mass transport of ions and oxygen vacancies. These processes, in turn, affect the dopant distribution throughout the surface and bulk laser crystal. By reducing proportionally more Yb3+ ions at the unmasked areas of component, than in the masked areas, the coordinate-dependent or spatially-controlled gain profiles are achieved.

Abstract: A laser medium comprises a solid-state host material and dopant species provided within the solid-state host material. A first portion of the dopant species has a first valence state, and a second portion of the dopant species has a second valence state. In an embodiment, a concentration of the first portion of the dopant species decreases radially with increasing distance from a center of the medium, and a concentration of the second portion of the dopant species increases radially with increasing distance from the center of the medium. The laser medium further comprises impurities within the solid-state host material, the impurities converting the first portion of the dopant species having the first valence state into the second portion of dopant species having the second valence state.

Abstract: Method of manufacturing a laser medium with a material having a surface and a dopant in the material distributed whereby the material has a spatially variant optical flux density profile uses tailored non-uniform gain profiles within a Yb:YAG laser component (rod, slab, disc, etc.) achieved by a spatial material modification in the spatially masked pre-forms. High temperature-assisted reduction leads to the coordinate-dependent gain profiles, which are controlled by the topology of the deposited solid masks. The gain profiles are obtained by reducing the charge state of the laser-active trivalent Yb3+ ions into inactive divalent Yb2+ ions. This valence conversion process is driven by mass transport of ions and oxygen vacancies. These processes, in turn, affect the dopant distribution throughout the surface and bulk laser crystal. By reducing proportionally more Yb3+ ions at the unmasked areas of component, than in the masked areas, the coordinate-dependent or spatially-controlled gain profiles are achieved.

Abstract: A material having a surface and a dopant in the material distributed whereby the material has a spatially variant optical flux density profile. In accordance with the invention, tailored non-uniform gain profiles within a Yb:YAG laser component (rod, slab, disc, etc.) are achieved by a spatial material modification in the spatially masked pre-forms. High temperature-assisted reduction leads to the coordinate-dependent gain profiles, which are controlled by the topology of the deposited solid masks. The gain profiles are obtained by reducing the charge state of the laser-active trivalent Yb3+ ions into inactive divalent Yb2+ ions. This valence conversion process is driven by mass transport of ions and oxygen vacancies. These processes, in turn, affect the dopant distribution throughout the surface and bulk laser crystal.

Abstract: A laser medium comprises a solid-state host material and dopant species provided within the solid-state host material. A first portion of the dopant species has a first valence state, and a second portion of the dopant species has a second valence state. In an embodiment, a concentration of the first portion of the dopant species decreases radially with increasing distance from a center of the medium, and a concentration of the second portion of the dopant species increases radially with increasing distance from the center of the medium. The laser medium further comprises impurities within the solid-state host material, the impurities converting the first portion of the dopant species having the first valence state into the second portion of dopant species having the second valence state.

Abstract: A thin disk laser includes a thin disk of a host material incorporating a laser gain medium. The disk has opposite first and second surfaces, at least one of which is non-planar. The first surface is coated with a high reflectivity coating. The second surface has an anti-reflection coating thereon. The shape and mounting of the laser is such that mismatch of the coefficients of thermal expansion between the disk laser and the mount does not affect scaling of the laser to larger size disks for higher power lasers.

Abstract: The present invention comprises a method and apparatus to increase the efficiency of photovoltaic conversion of light into electrical power and to achieve operation at higher optical power and therefore higher electrical power. Preferred embodiments increase the efficiency of photovoltaic power conversion of any source of a beam of photons by spatially dividing the beams into a plurality of individual beamlets, each beamlet focusing on an active photovoltaic region. The preferred architecture of the apparatus of the invention comprises spatially separated photovoltaic cells to substantially match the pattern of the spatially separated plurality of beamlets. Preferred embodiments result in a significant reduction in ohmic losses and current shunting, thereby increasing photovoltaic conversion efficiencies.

Abstract: A laser rod is provided having a tailored gain profile such that the quality of the output beam is enhanced. The laser rod has a concentration of active substitutional ions that is relatively high at the center of the rod and decreases to the surface of the rod. The laser rod further has a concentration of pre-active laser ions that is relatively high at the surface of the rod and decreases to the center of the rod. Methods are disclosed for creating a layer of inactive laser species in the near surface region of a laser rod using substitutional dopant ions and for creating a laser rod with a tailored gain profile such that the quality of the output beam is enhanced.

Abstract: A laser rod is provided having a tailored gain profile such that the quality of the output beam is enhanced. The laser rod has a concentration of dopant ions having a first valence that is relatively high at the center of the rod and decreases to the surface of the rod. The laser rod further has a concentration of interstitial ions and dopant ions having a second valence that is lower than the first valence, the concentration being relatively high at the surface of the rod and decreasing to the center of the rod. Methods are provided for creating a layer of inactive laser species in the near surface region of a laser rod using interstitial dopant ions and for reducing the near surface absorption of incident photons intended to induce lasing in a laser rod using a layer of inactive laser ions.

Abstract: A thin disk laser includes a thin disk of a host material incorporating a laser gain medium. The disk has opposite first and second surfaces, at least one of which is non-planar. The first surface is coated with a high reflectivity coating. The second surface has an anti-reflection coating thereon.

Abstract: A laser rod is provided having a tailored gain profile such that the quality of the output beam is enhanced. The laser rod has a concentration of dopant ions having a first valence that is relatively high at the center of the rod and decreases to the surface of the rod. The laser rod further has a concentration of interstitial ions and dopant ions having a second valence that is lower than the first valence, the concentration being relatively high at the surface of the rod and decreasing to the center of the rod. Methods are provided for creating a layer of inactive laser species in the near surface region of a laser rod using interstitial dopant ions and for reducing the near surface absorption of incident photons intended to induce lasing in a laser rod using a layer of inactive laser ions.

Abstract: A laser rod is provided having a tailored gain profile such that the quality of the output beam is enhanced. The laser rod has a concentration of active substitutional ions that is relatively high at the center of the rod and decreases to the surface of the rod. The laser rod further has a concentration of pre-active laser ions that is relatively high at the surface of the rod and decreases to the center of the rod. Methods are disclosed for creating a layer of inactive laser species in the near surface region of a laser rod using substitutional dopant ions and for creating a laser rod with a tailored gain profile such that the quality of the output beam is enhanced.

Abstract: A solid state pump cavity comprising a laser rod encased by diffusion bonding inside an outer cladding. The outer cladding provides the ability to efficiently conduct heat away from the laser rod. The outer cladding is also configured to absorb spontaneous laser radiation that would otherwise be re-amplified by the laser rod. Diffusion bonding of the outer cladding to the laser rod forms a seamless optical boundary between the outer cladding and the laser rod. An alternative embodiment of the pump cavity comprises multiple segments of laser rod and outer cladding assemblies coupled together with undoped sections that are diffusion bonded to the ends of the laser rod and outer cladding assemblies.

Abstract: A method and apparatus for optimizing the numerical aperture (NA) of a laser active core. The laser active core comprises at least a first and second cladding pair. The first and second cladding pair have at least one NA value. At least one of the first and second cladding pair is doped with a dopant to change the first NA value to a second NA value.

Abstract: A system and a method for providing more gain while minimizing the potential for parasitic oscillation and amplified spontaneous emissions in an optically pumped optical amplifier or laser system, utilizing a partitioned monolithic gain element. The monolithic gain element being partitioned into discontinuous amplifying gain regions such that parasitic modes and amplified spontaneous emissions are substantially obviated.

Abstract: A waveguide is fabricated by first preparing two waveguide precursor pieces. Each waveguide precursor piece includes a single-crystal substrate, and an epitaxial coating layer of an oxide coating material on the substrate. The oxide substrate material preferably comprises yttrium as a substrate-material cation, and the oxide coating material preferably comprises a coating-material cation selected from the group consisting of ytterbium, thulium, erbium, and holmium. The two substrates are placed together with the coating layers in contact to form a precursor structure. The precursor structure is heated to an elevated diffusion temperature so that the coating layers bond together and the coating materials and the respective substrate materials interdiffuse to form the waveguide having an interdiffused region. A laser beam may be directed through the interdiffused region, while the interdiffused region is optionally optically pumped through one or both of the substrates.

Abstract: A system and a method for providing more gain while minimizing the potential for parasitic oscillation and amplified spontaneous emissions in an electrically pumped optical amplifier or laser system, utilizing a partitioned monolithic gain element. The monolithic gain element being partitioned into discontinuous amplifying gain regions such that parasitic modes and amplified spontaneous emissions are substantially obviated.