Broadband thermal imaging using meta-optics.

Subwavelength diffractive optics known as meta-optics have demonstrated the potential to significantly miniaturize imaging systems. However, despite impressive demonstrations, most meta-optical imaging systems suffer from strong chromatic aberrations, limiting their utilities. Here, we employ inverse-design to create broadband meta-optics operating in the long-wave infrared (LWIR) regime (8-12 μm).

Thermal modeling of electrically-pumped continuous-wave microring resonator-based topological insulator lasers.

Deleterious effects caused by Joule heating in electrically-pumped continuous-wave InP-based topological insulator lasers based on two-dimensional microring resonator arrays are estimated in this theoretical study. Steady-state temperature distributions within such an array are developed using a full numerical solution. Thermal interactions between active gain regions and ring resonators pose significant operational and integration challenges, as these devices are extremely sensitive to temperature-induced changes in a material's index of refraction.

500 W peak power cavity dumped 2 µm GaSb-based VECSEL.

A single transverse mode high-pulse-energy vertical-external-cavity surface-emitting laser (VECSEL) was developed. The GaSb-based VECSEL emits at a wavelength of 2.04 µm with a peak power exceeding 500 W while maintaining good beam quality.

VECSEL-based virtually imaged phased array spectrometer for rapid gas phase detection in the mid-infrared.

We present a novel, to the best of our knowledge, system for high-resolution, time-resolved spectroscopy in the mid-wave infrared based on a modelocked vertical external cavity surface emitting laser (VECSEL) frequency comb coupled to a virtually imaged phased array (VIPA) spectrometer. The GHz level repetition rate of VECSEL-based systems coupled to VIPA spectrometers enables comb tooth resolved spectra without the use of additional filter cavities often required to increase comb tooth spacing. We demonstrate absorption spectroscopy on a methane () gas mixture at 2900 (3.

Angle- and polarization-independent mid-infrared narrowband optical filters using dense arrays of resonant cavities.

We report design and experimental verification of narrowband mid-infrared optical filters with transmission characteristics that are practically constant over a wide range of incident angles. The filter employs a dense array of dielectric resonant cavities in a metal film, where the transmission of each cavity depends upon localized rather than travelling fields, making the filter fundamentally angle-independent. We show experimentally a transmission around 90% from normal incidence up to 60°.

Controlling three-dimensional optical fields via inverse Mie scattering.

Controlling the propagation of optical fields in three dimensions using arrays of discrete dielectric scatterers is an active area of research. These arrays can create optical elements with functionalities unrealizable in conventional optics. Here, we present an inverse design method based on the inverse Mie scattering problem for producing three-dimensional optical field patterns.

Generation of near-diffraction-limited, high-power supercontinuum from 1.57 μm to 12 μm with cascaded fluoride and chalcogenide fibers.

We generate a supercontinuum (SC) spectrum ranging from 1.57 μm to 12 μm (20 dB bandwidth) with a soft glass fiber cascade consisting of ---- fiber, fiber, and fiber pumped by a nanosecond thulium master oscillator power amplifier system. The highest on-time average power generated is 417 mW at 33% duty cycle.

Mid-infrared supercontinuum generation from 1.6 to >11 μm using concatenated step-index fluoride and chalcogenide fibers.

We demonstrate an all-fiber supercontinuum source that generates a continuous spectrum from 1.6 μm to >11  μm with 417 mW on-time average power at 33% duty cycle. By utilizing a master oscillator power amplifier pump with three amplification stages and concatenating solid core ZBLAN, arsenic sulfide, and arsenic selenide fibers, we shift 1550 nm light to ∼4.

Improved 2 × 2 Mach-Zehnder switching using coupled-resonator photonic-crystal nanobeams.

Design and simulation results are presented for an on-chip 2×2 Mach-Zehnder-based optical switch where each arm of the interferometer is composed of a coupled-resonator optical waveguide. The individual resonators are one-dimensional photonic crystal nanobeam cavities, and switching occurs through thermally induced changes in the refractive index of the silicon structure using integrated heating pads. The performance of the coupled-resonator device is directly compared to its single resonator counterpart, and significant improvement is found in the bar-state CT metric.

2,2,3,3'-Tetra-phenyl-7,7'-biquinoxaline.

In the crystal structure of the title compound, C(40)H(26)N(4), mol-ecules reside on crystallographic centers of inversion and are linked via C-H⋯N inter-actions about inversion centers into one-dimensional chains: longer C-H⋯π(arene) inter-actions complete the inter-molecular inter-actions.