No abstract

We report for the first time on the redox multiphoton polymerization of an organic-inorganic composite material, in which one of the components, a vanadium metallo-organic complex, initiates the polymerization. The composite employs multiphoton absorption to self-generate radicals by photoinduced reduction of the metal species from vanadium (V) to vanadium (IV). We exploit this material for the fabrication of fully 3D structures by multiphoton polymerization with 200 nm resolution, employing a femtosecond laser operating at 800 nm, in the absence of a photoinitiator. Nonlinear absorption measurements indicate that the use of an 800 nm laser initiates the photopolymerization due to three-photon absorption of the vanadium alkoxide. The laser power required to induce this three-photon polymerization is comparable to what is required for inducing two-photon polymerization in materials using standard two-photon absorbers, most likely due to the high content of vanadium in the final composite (up to 50% mole).

Diamond has attracted great interest as a quantum technology platform thanks to its optically active nitrogen vacancy (NV) center. The NV's ground state spin can be read out optically, exhibiting long spin coherence times of ≈1 ms even at ambient temperatures. In addition, the energy levels of the NV are sensitive to external fields. These properties make NVs attractive as a scalable platform for efficient nanoscale resolution sensing based on electron spins and for quantum information systems. Diamond photonics enhance optical interactions with NVs, beneficial for both quantum sensing and information. Diamond is also compelling for microfluidic applications due to its outstanding biocompatibility, with sensing functionality provided by NVs. However, it remains a significant challenge to fabricate photonics, NVs, and microfluidics in diamond. In this Progress Report, an overview is provided of ion irradiation and femtosecond laser writing, two promising fabrication methods for diamond‐based quantum technological devices. The unique capabilities of both techniques are described, and the most important fabrication results of color center, optical waveguide, and microfluidics in diamond are reported, with an emphasis on integrated devices aiming toward high performance quantum sensors and quantum information systems of tomorrow.