Additive Manufacturing of Sesquioxide Ceramic Thin-Disk Gain Media with a Tailored Dopant Profile for Short-Pulse, High Average Power Lasers

The Problem Being Addressed The laser-based electron accelerator is an innovative tool to obtain GeV to TeV electron energies for high-energy particle physics experiments. The development of high-power laser systems for these accelerators, however, puts stringent challenges on the very limits of the laser materials themselves. The enormous heat generated by the high power creates great thermal stress that leads to effects such as birefringence, thermal lensing, or even physical fracture damage to the host. The issue can be mitigated by using fiber or thin-disk lasers with effective cooling. The next generation of accelerators, however, will require higher powers than can be produced by the current state-of-the-art. To address this challenge, RMD and our STTR partner, Lawrence Livermore National Laboratory will investigate the design and fabrication of thin-disk ceramic composite laser gain media with a 3-D doping profile. Ceramics offer other advantages over single crystals in providing the flexibility to tailor the doping concentration and profile with lower inherent cost, higher yield, relaxed constraints on size and shape, and control of composition. In addition, ceramics are generally more robust than single crystals toward thermal or mechanical shock and resistant to mechanical and thermal damage. Yb-doped sesquioxide possesses a cubic structure and high thermal conductivity and is a well-known candidate for the short pulse, high-power laser gain media application. During the Phase II study, we will design and fabricate Yb-doped sesquioxide thin disk gain media suitable for high-power, short pulse lasers with a built-in 3D doping profile to improve the gain distribution, fine-tune the process to produce transparent ceramic disks with the appropriate doping gradient structure, , characterize the physical, and optical properties of the thin gain media discs., fabricate and test a high quality 25-40mm ceramic disks suitable for constructing a 3kW laser. Finally, we will demonstrate a diode-pumped thin disk laser with a tailored doping profile. There are two target markets for our technology. The first segment consists of national labs and universities both in the U.S. and globally that will want to use our technology for scientific research and in current and future high-power laser accelerators. This market is typically categorized as part of the scientific research and military market. Global revenue for laser systems used in the scientific research and military markets grew from $922 million in 2017 to $2.248 billion in 2020 The second market segment is the materials processing and lithography market. This market includes lasers used for all types of metal processing (welding, cutting, annealing, drilling); semiconductor and microelectronics manufacturing (lithography, scribing, defect repair, via drilling); The lithography equipment segment is used to print complex circuit patterns on silicon wafers that are mainly raw materials for integrated circuits. This process is considered to be one of the most expensive and critical steps in wafer fabrication.