Supercontinuum generation in angle-etched diamond waveguides.

We experimentally demonstrate on-chip supercontinuum generation in the visible region in angle-etched diamond waveguides. We measure an output spectrum spanning 670-920 nm in a 5-mm-long waveguide using 100-fs pulses with 187 pJ of incident pulse energy. Our fabrication technique, combined with diamond's broad transparency window, offers a potential route toward broadband supercontinuum generation in the UV domain.

Integrated diamond Raman laser pumped in the near-visible.

Using a high-Q diamond microresonator (Q>300,000) interfaced with high-power-handling directly-written doped-glass waveguides, we demonstrate a Raman laser in an integrated platform pumped in the near-visible. Both TM-to-TE and TE-to-TE lasing is observed, with a Raman lasing threshold as low as 20 mW and Stokes power of over 1 mW at 120 mW pump power. Stokes emission is tuned over a 150 nm (60 THz) bandwidth of approximately 875 nm wavelength, corresponding to 17.5% of the center frequency.

Competition between Raman and Kerr effects in microresonator comb generation.

We investigate the effects of Raman and Kerr gain in crystalline microresonators and determine the conditions required to generate mode-locked frequency combs. We show theoretically that a strong, narrowband Raman gain determines a maximum microresonator size allowable to achieve comb formation. We verify this condition experimentally in diamond and silicon microresonators and show that there exists a competition between Raman and Kerr effects that leads to the existence of two different comb states.

Scalable method for the fabrication and testing of glass-filled, three-dimensionally sculpted extraordinary transmission apertures.

This Letter features a new, scalable fabrication method and experimental characterization of glass-filled apertures exhibiting extraordinary transmission. These apertures are fabricated with sizes, aspect ratios, shapes, and side-wall profiles previously impossible to create. The fabrication method presented utilizes top-down lithography to etch silicon nanostructures. These nanostructures are oxidized to provide a transparent template for the deposition of a plasmonic metal. Gold is deposited around these structures, reflowed, and the surface is planarized. Finally, a window is etched through the substrate to provide optical access. Among the structures created and tested are apertures with height to diameter aspect ratios of 8:1, constructed with rectangular, square, cruciform, and coupled cross sections, with tunable polarization sensitivity and displaying unique properties based on their sculpted side-wall shape. Transmission data from these aperture arrays is collected and compared to examine the role of spacing, size, and shape on their overall spectral response. The structures this Letter describes can have a variety of novel applications from the creation of new types of light sources to massively multiplexed biosensors to subdiffraction limit imaging techniques.

Diamond mirrors for high-power continuous-wave lasers.

High-power continuous-wave (CW) lasers are used in a variety of areas including industry, medicine, communications, and defense. Yet, conventional optics, which are based on multi-layer coatings, are damaged when illuminated by high-power CW laser light, primarily due to thermal loading. This hampers the effectiveness, restricts the scope and utility, and raises the cost and complexity of high-power CW laser applications. Here we demonstrate monolithic and highly reflective mirrors that operate under high-power CW laser irradiation without damage. In contrast to conventional mirrors, ours are realized by etching nanostructures into the surface of single-crystal diamond, a material with exceptional optical and thermal properties. We measure reflectivities of greater than 98% and demonstrate damage-free operation using 10 kW of CW laser light at 1070 nm, focused to a spot of 750 µm diameter. In contrast, we observe damage to a conventional dielectric mirror when illuminated by the same beam. Our results initiate a new category of optics that operate under extreme conditions, which has potential to improve or create new applications of high-power lasers.

Large-scale quantum-emitter arrays in atomically thin semiconductors.

Quantum light emitters have been observed in atomically thin layers of transition metal dichalcogenides. However, they are found at random locations within the host material and usually in low densities, hindering experiments aiming to investigate this new class of emitters. Here, we create deterministic arrays of hundreds of quantum emitters in tungsten diselenide and tungsten disulphide monolayers, emitting across a range of wavelengths in the visible spectrum (610-680 nm and 740-820 nm), with a greater spectral stability than their randomly occurring counterparts. This is achieved by depositing monolayers onto silica substrates nanopatterned with arrays of 150-nm-diameter pillars ranging from 60 to 190 nm in height. The nanopillars create localized deformations in the material resulting in the quantum confinement of excitons. Our method may enable the placement of emitters in photonic structures such as optical waveguides in a scalable way, where precise and accurate positioning is paramount.