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Lens-coupled X-ray computed tomography (X-ray CT) using a transparent scintillator imaged on a CCD camera obtains higher spatial resolution than the more commonly employed phosphor-enhanced amorphous silicon (A-Si) panels. A-Si panels are limited to resolution typically greater than ~200 microns, have a limited working life due to degradation with dose, and provide intrinsically low efficiency with thin (few hundred microns thick) phosphor coatings. Demanding applications such as imaging the interior of complex additively manufactured components require high throughput and high resolution, best achieved with a lens-coupled system. However, for large fields-of-view, very large area but thin transparent scintillators are required – a format difficult to fabricate with high light yield single crystals – therefore, glass scintillators with both modest X-ray interaction and light yield have been used for years. We have developed a new polycrystalline transparent ceramic scintillator, Gd0.3Lu1.6Eu0.1O3, or “GLO,” that offers excellent stopping power and light yield for improved contrast in sizes up to 14” x 14” plates, with thicknesses in the 2-10 mm range, and we are implementing it in systems to increase imaging throughput for 9 MeV Bremsstrahlung X-ray CT. CT imaging performance will be described.

A novel type of Yb:YAG transparent ceramic thin disk laser amplifier is demonstrated, based on fabricating a composite gain element with a paraboloidal interface between gain and no-gain regions and employing side-pumping of the thin disk. The pump-induced gain and the impact of amplified spontaneous emission on the achievable inversion are reported.

Transparent ceramic fabrication via solid state sintering is opening a path to a new category of laser gain media with tailor-made doping and index profiles. Techniques such as assembly of green structure pieces, direct ink writing, and Ink jet printing allow the fabrication of a wide variety of tailored optics including; slabs, rods, gradient doping, thin disks, ceramic-clad single-crystal fibers, and planar waveguides. The potential for 3D printed gain media to have a profound impact on new laser design and integrated optics is yet untapped. This work was performed under the auspices of the U.S. DOE by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. LLNL-ABS-816729

Spatially distinct and graded doping profiles may be formed in YAG transparent ceramic laser gain media via additive manufacturing. Near-uniform refractive index may be obtained with co-doping of the undoped region with a compensating ion.

A new, to the best of our knowledge, 3D additive manufacturing technique utilizing particle-loaded ink jet printing to fabricate transparent ceramic Yb:YAG planar waveguides for laser gain media was demonstrated. Rheological optimization of YAG particle-loaded inks resulted in successful droplet formation and printing resolution. Planar waveguides composed of a Yb:YAG guide encased in undoped YAG cladding were printed with guide thicknesses ranging between 25 and 350 µm and consolidated to high optical quality via solid-state sintering. Sufficiently low optical (1–3%/cm) and intermodal scatter allowed single-mode propagation with a core/clad index difference of Δ n ∼ 5.0 × 10 − 4 (corresponding to 3 at.% Yb). The waveguides were cladding-pumped longitudinally with a 940 nm diode array resulting in 23.6% slope efficiency in 2 ms pulsed operation.