Laser-induced structural modification in calcium aluminosilicate glasses using molecular dynamic simulations.

Glass structures of multicomponent oxide systems (CaO-AlO-SiO) are studied using a simulated pulsed laser with molecular dynamics. The short- and intermediate-range order structures revealed a direct correlation between the transformation of Al to Al, regions of increased density following laser processing, inherent reduction in the average T-O-T (T = Al, Si) angle, and associated elongation of the T-O bonding distance. Variable laser pulse energies were simulated across calcium aluminosilicate glasses with high silica content (50-80%) to identify densification trends attributed to composition and laser energy.

Using phase-corrected Bessel beams to cut glass substrates with a chamfered edge.

Ultrafast laser cutting of a glass substrate at an oblique angle is demonstrated using a phase-corrected Bessel beam. Simulations are used to predetermine the ideal phase of the incident Bessel beam such that an unaberrated Bessel beam is formed inside the tilted substrate. Additional corrections to the beam such as shortening, moving the intensity of the beam within the substrate, and the formation of an elliptical focal spot were necessary to ensure consistent chamfering of the substrate and are discussed herein.

Design of emitter structures based on resonant perfect absorption for thermophotovoltaic applications.

We report a class of thermophotovoltaic emitter structures built upon planar films that support resonant modes, known as perfectly-absorbing modes, that facilitate an exceptional optical response for selective emission. These planar structures have several key advantages over previously-proposed designs for TPV applications: they are simple to fabricate, are stable across a range of temperatures and conditions, and are capable of achieving some of the highest spectral efficiencies reported of any class of emitter structure. Utilization of these emitters leads to exceptionally high device efficiencies under low operating temperature conditions, which should open new opportunities for waste heat management.

Graded-index structures for high-efficiency solar thermophotovoltaic emitting surfaces.

This Letter presents a highly efficient emitter structure for solar thermophotovoltaic systems. The structure consists of a graded index on tungsten, shows a spectral efficiency of 59%, or 70% with the use of a back reflector, and is compared to other state-of-the-art emitter structures. The effects of different structures and periodicities on the efficiency of the emitter are explored, as well as the effect of a protective oxide coating.

Solar thermophotovoltaic system using nanostructures.

This paper presents results on a highly efficient experimental solar thermophotovoltaic (STPV) system using simulated solar energy. An overall power conversion efficiency of 6.2% was recorded under solar simulation.

Optical and infrared properties of glancing angle-deposited nanostructured tungsten films.

Nanotextured tungsten thin films were obtained on a stainless steel (SS) substrate using the glancing-angle-deposition (GLAD) method. It was found that the optical absorption and thermal emittance of the SS substrate can be controlled by varying the parameters used during deposition. Finite-difference time-domain (FDTD) simulations were used to predict the optical absorption and infrared (IR) reflectance spectra of the fabricated samples, and good agreement was found between simulated and measured data.