Interferometric metrology probe for highly sloped freeform optics.

A wide variety of systems are employed to measure the surface profile of aspheric and freeform optical surfaces. Freeform metrology systems must accurately characterize the full surface under test, which can be difficult with steep surface slopes. Here we present an interferometric surface metrology probe for highly sloped aspheric and freeform optical surfaces.

Dish-based high concentration PV system with Köhler optics.

We present work at the Steward Observatory Solar Lab on a high concentration photovoltaic system in which sunlight focused by a single large paraboloidal mirror powers many small triple-junction cells. The optical system is of the XRX-Köhler type, comprising the primary reflector (X) and a ball lens (R) at the focus that reimages the primary reflector onto an array of small reflectors (X) that apportion the light to the cells. We present a design methodology that provides generous tolerance to mis-pointing, uniform illumination across individual cells, minimal optical loss and even distribution between cells, for efficient series connection.

Dish-based high concentration PV system with Köhler optics.

We present work at the Steward Observatory Solar Lab on a high concentration photovoltaic system in which sunlight focused by a single large paraboloidal mirror powers many small triple-junction cells. The optical system is of the XRX-Köhler type, comprising the primary reflector (X) and a ball lens (R) at the focus that reimages the primary reflector onto an array of small reflectors (X) that apportion the light to the cells. We present a design methodology that provides generous tolerance to mis-pointing, uniform illumination across individual cells, minimal optical loss and even distribution between cells, for efficient series connection.

Strong ionic hydrogen bonding causes a spectral isotope effect in photoactive yellow protein.

Standard hydrogen bonds are of great importance for protein structure and function. Ionic hydrogen bonds often are significantly stronger than standard hydrogen bonds and exhibit unique properties, but their role in proteins is not well understood. We report that hydrogen/deuterium exchange causes a redshift in the visible absorbance spectrum of photoactive yellow protein (PYP).

A ground-layer adaptive optics system with multiple laser guide stars.

To determine the influence of the environment on star formation, we need to study the process in the extreme conditions of massive young star clusters ( approximately 10(4) solar masses) near the centre of our own Galaxy. Observations must be carried out in the near infrared because of very high extinction in visible light within the Galactic plane. We need high resolution to identify cluster members from their peculiar motions, and because most such clusters span more than 1', efficient observation demands a wide field of view.