Diffractive optical elements utilized for efficiency enhancement of photovoltaic modules.

Common solar cells used in photovoltaic modules feature metallic contacts which partially block the sunlight from reaching the semiconductor layer and reduce the overall efficiency of the modules. Diffractive optical elements were generated in the bulk glass of a photovoltaic module by ultrafast laser irradiation to direct light away from the contacts. Calculations of the planar electromagnetic wave diffraction and propagation were performed using the rigorous coupled wave analysis technique providing quantitative estimations for the potential efficiency enhancement of photovoltaic modules.

Study of two different thin film coating methods in transmission laser micro-joining of thin Ti-film coated glass and polyimide for biomedical applications.

Biomedical devices and implants require precision joining for hermetic sealing which can be achieved with low power lasers. The effect of two different thin metal film coating methods was studied in transmission laser micro-joints of titanium-coated glass and polyimide. The coating methods were cathodic arc physical vapor deposition (CA-PVD) and electron beam evaporation (EB-PVD).

Postimplantation pressure testing and characterization of laser bonded glass/polyimide microjoints.

The stability of the laser bonded titanium coated glass/polyimide microjoints were studied in vivo by implanting on a rat brain surface for 10 days. In the current state, the strength of the joints were measured by a specially designed instrument called "pressure test" equipment where the samples were subjected to a variable pressure load (using high pressure nitrogen) controlled by a pressure regulator. The strength of the joints seems to degrade by about 28% as a result of soaking in rat brain.

Performance of laser bonded glass/polyimide microjoints in cerebrospinal fluid.

In this paper, laser bonded microjoints between glass and polyimide is considered to examine their potential applicability in encapsulating neural implants. To facilitate bonding between polyimide and glass, a thin titanium film with a thickness of 2 microm was deposited on borosilicate glass plates by a physical vapor deposition (PVD) process. Titanium coated glass was then joined with polyimide by using a cw fiber laser emitting at a wavelength of 1.

A comparison between glass/polyimide and titanium/polyimide microjoint performances in cerebrospinal fluid.

Assessment of neural biocompatibility requires that materials be tested with exposure in neural fluids. Laser bonded microjoint samples made from Ti coated glass substrate and polyimide film (GPI) and titanium foil and polyimide film (TIPI) were evaluated for mechanical performance before and after exposure in artificial cerebrospinal fluid (CSF) for two, four, and 12 weeks at 37 degrees C. These samples represent a critical feature, i.