Tunable solid-body elastomer lenses with electromagnetic actuation.

We present novel biconvex solid-body elastomer (polydimethylsiloxane) lenses, which can be tuned in focal length by using magnetic or mechanical actuation. The focal length change is induced by applying radial elastic strain and is investigated for different initial radii of curvature of the lenses and different actuation designs. In all cases, a linear correlation between induced strain and focal length tuning, in the range of about 10% (approximately 3 mm), is found. These results compare favorably with finite element simulations.

Biochip reader with dynamic holographic excitation and hyperspectral fluorescence detection.

A highly parallel microarray scanner for functional genomic research using a dynamically reconfigurable holographic excitation and hyperspectral fluorescence detection is described. The light from two laser sources (405 and 532 nm) is split into an arbitrary number of focused spots on the biochip using a pair of spatial light modulators and a novel imaging system. The parallel optical scanner includes a hyperspectral detection unit with a high-sensitivity CCD camera to detect and analyze the emitted fluorescence spectra (from 430 to 800 nm) of all illuminated spots simultaneously. By using an xy scanner, the spectra of all spots on an entire array can be read out line by line.

Replicated, high-aspect-ratio micro-optical components fabricated from inorganic solgel materials.

A replication process for the fabrication of refractive microlenses from a purely inorganic solgel material based on tetraethoxysilane is presented. The geometrical dimensions and optical properties of the inorganic microlenses are characterized and compared with those of microlenses replicated in a hybrid xerogel containing organic additives. By a reduced solvent content in the sol composition, together with modifications in the replication process, it was possible to obtain inorganic xerogel lenses with exceptionally high sagittal height values of as much as 28 microm. Compared with the hybrid xerogel, the inorganic xerogel has the advantage of an absorption coefficient that is five times lower in the visible spectral range and exhibits optical transparency in the near-ultraviolet range for wavelengths down to 200 nm.

Tunable Bragg filters based on polymer swelling.

We report on the optical properties of Bragg mirrors and filters fabricated from photo-cross-linked standard optical polymers. The transmittance spectra of these devices in the visible to near-infrared spectral range were measured. We demonstrate efficient tuning of the filter peak of the polymer Bragg filters over several hundred nanometers by adding organic solvents to the surrounding atmosphere of the filter. This represents what we believe to be a novel tuning principle for Bragg filters relying on the use of polymeric materials.