Invention enables manufacturers to produce high-power laser amplifiers that suppress transverse oscillations while operating in both cryogenic and high-vacuum environments
UCF researchers have developed a low-cost, non-toxic cladding material that suppresses the unwanted effects of transverse and parasitic oscillations that occur with high-powered lasers. The new cladding resolves the key performance issues associated with solid-state, single-crystal and ceramic laser amplifiers of such lasers.
Thermal heating from higher pumping powers can degrade laser quality or cause catastrophic damage inside the laser itself. To avoid this problem, laser users must limit the laser’s repetition rate or run expensive cryogenic cooling systems. In addition, larger laser mediums can cause spontaneous emission, which triggers parasitic and transverse oscillations that can deplete the population inversion needed to amplify light. Though some existing absorber-doped, index-matched claddings can suppress transverse oscillations, such materials are incompatible with high vacuum and cryogenic environments. To resolve the oscillation and amplification issues, the new invention employs a low-cost cladding material that is the same as the core material and is easy-to-handle. The solid-state, index-matched cladding is also stable and compatible with both cryogenic cooling methods and high-vacuum environments.
The invention comprises a cladding material and methods for forming the cladding and using it to suppress transverse oscillations in solid-state, single-crystal or ceramic laser amplifiers. The cladding material is the same as the core (amplifier) material; for example, if the core is sapphire, then the cladding could be alumina-doped sapphire. In another example, the cladding material could be a polycrystalline form of the core material. Additionally, the cladding material includes a broadband absorber material such as alumina, graphene, a rare earth ion, a transitional metal ion or a p-block element. Thus, by matching the cladding material with the core material and then doping the cladding with a broadband absorber, its refractive index matches the core’s index for all wavelengths and can suppress transverse oscillations across broad bandwidths. The cladding can be formed using various steps or combinations of steps including pressing or depositing the absorber-doped ceramic powder on the core material and sintering it to full density under a heat treatment. Another method consists of in-diffusing the broadband absorber material at the periphery of the core through either controlled thermal annealing or through electrochemical processes.
- Easy to handle, non-toxic, stable and cryogenic- and vacuum-compatible
- Avoids thermal expansion mismatching at the core-cladding interface
- Provides uniform broadband absorption across the visible and near-IR spectrum
- High-energy or high-power solid-state, single-crystal laser systems
- Medical devices
- Military defense