All fiber watt-level fiber source at 760 nm generated through four-wave mixing in a photonic crystal fiber.

There are limited fiber-based single-mode laser sources over the visible and near infrared range. Nonlinear conversion through four-wave mixing in photonic crystal fibers allows for the generation of new wavelengths far from a pump wavelength. Utilizing an all-fiber spliced configuration, we convert 1064 nm light into a W-level signal in the 750 nm - 820 nm spectral region.

Infrared glass-based negative-curvature anti-resonant fibers fabricated through extrusion.

Negative curvature fibers have been gaining attention as fibers for high power infrared light. Currently, these fibers have been made of silica glass and infrared glasses solely through stack and draw. Infrared glasses' lower softening point presents the opportunity to perform low-temperature processing methods such as direct extrusion of pre-forms.

Fabrication tolerances in AsS negative-curvature antiresonant fibers.

We computationally investigate fabrication tolerances in AsS negative-curvature antiresonant tube-lattice fibers. Since the dominant loss mechanisms for silica in the mid-infrared (mid-IR) is material absorption, AsS, which offers a reduced loss over that wavelength range, is a natural candidate for mid-IR antiresonant fibers. However, any fiber fabrication technology, including for soft glasses, will have imperfections.

Review of infrared fiber-based components.

The infrared range of the optical spectrum is attractive for its use in sensing, surveillance, and material characterization. The increasing availability of compact laser sources and detectors in the infrared range stands in contrast with the limited development of optical components for this optical range. We highlight developments of infrared components with a particular focus on fiber-based components for compact optical devices and systems.

Low-loss, robust fusion splicing of silica to chalcogenide fiber for integrated mid-infrared laser technology development.

We demonstrate a low-loss, repeatable, and robust splice between single-mode silica fiber and single-mode chalcogenide (CHG) fiber. These splices are particularly difficult to create because of the significant difference in the two fibers' glass transition temperatures (∼1000°C) as well as the large difference in the coefficients of thermal expansion between the fibers (∼20×10(-6)/°C). With 90% light coupled through the silica-CHG fiber splice, predominantly in the fundamental circular-symmetric mode, into the core of the CHG fiber and with 0.

Microchip laser mid-infrared supercontinuum laser source based on an As2Se3 fiber.

We report on a proof of concept for a compact supercontinuum source for the mid-infrared wavelength range based on a microchip laser and nonlinear conversion inside a selenide-based optical fiber. The spectrum extends from 3.74 to 4.

Multiphoton photoresists giving nanoscale resolution that is inversely dependent on exposure time.

Recent advances in materials science have made it possible to perform photolithography at the nanoscale using visible light. One approach to visible-light nanolithography (resolution augmentation through photo-induced deactivation) uses a negative-tone photoresist incorporating a radical photoinitiator that can be excited by two-photon absorption. With subsequent absorption of light, the photoinitiator can also be deactivated before polymerization occurs.

Achieving lambda/20 resolution by one-color initiation and deactivation of polymerization.

In conventional photolithography, diffraction limits the resolution to about one-quarter of the wavelength of the light used. We introduce an approach to photolithography in which multiphoton absorption of pulsed 800-nanometer (nm) light is used to initiate cross-linking in a polymer photoresist and one-photon absorption of continuous-wave 800-nm light is used simultaneously to deactivate the photopolymerization. By employing spatial phase-shaping of the deactivation beam, we demonstrate the fabrication of features with scalable resolution along the beam axis, down to a 40-nm minimum feature size.

Faraday rotation in femtosecond laser micromachined waveguides.

We demonstrate magneto-optic switching in femtosecond-laser micromachined waveguides written inside bulk terbium-doped Faraday glass. By measuring the polarization phase shift of the light as a function of the applied magnetic field, we find that there is a slight reduction in the effective Verdet constant of the waveguide compared to that of bulk Faraday glass. Electron Paramagnetic Resonance (EPR) measurements confirm that the micromachining leaves the concentration of the terbium ions that are responsible for the Faraday effect virtually unchanged.

Supercontinuum generation in submicrometer diameter silica fibers.

Silica nanowires provide strong mode confinement in a cylindrical silica-core/air-cladding geometry and serve a model system for studying nonlinear propagation of short optical pulses inside fibers. We report on the fiber diameter dependence of the supercontinuum generated by femtosecond laser pulses in silica fiber tapers with average diameters in the range of 200 nm to 1200 nm. We observe a strong diameter-dependence of the spectral broadening, which can be attributed to the fiber's diameter-dependent dispersion and nonlinearity.

Micromachining of bulk glass with bursts of femtosecond laser pulses at variable repetition rates.

Oscillator-only femtosecond laser micromachining enables the manufacturing of integrated optical components with circular transverse profiles in transparent materials. The circular profile is due to diffusion of heat accumulating at the focus. We control the heat diffusion by focusing bursts of femtosecond laser pulses at various repetition rates into sodalime glass.

Assembly of silica nanowires on silica aerogels for microphotonic devices.

We report on the assembly of low-loss silica nanowires into functional microphotonics devices on a low-index nondissipative silica aerogel substrate. Using this all-silica technique, we fabricated linear waveguides, waveguide bends, and branch couplers. The devices are significantly smaller than existing comparable devices and have low optical loss, indicating that the all-silica technique presented here has great potential for future applications in optical communication, optical sensing, and high-density optical integration.

Subwavelength-diameter silica wires for low-loss optical wave guiding.

Silica waveguides with diameters larger than the wavelength of transmitted light are widely used in optical communications, sensors and other applications. Minimizing the width of the waveguides is desirable for photonic device applications, but the fabrication of low-loss optical waveguides with subwavelength diameters remains challenging because of strict requirements on surface roughness and diameter uniformity. Here we report the fabrication of subwavelength-diameter silica 'wires' for use as low-loss optical waveguides within the visible to near-infrared spectral range.