A method (1) creates charge carriers in a concentration that changes in a periodic manner (also called "modulation") only with respect to time, and (2) determines the number of charge carriers created in the carrier creation region by measuring an interference signal obtained by interference between a reference beam and a portion of a probe beam that is reflected by charge carriers at various depths of the semiconductor material, and comparing the measurement with corresponding values obtained b...

Apparatus for splitting, imaging, and measuring wavefronts with a reference wavefront and an object wavefront. A wavefront-combining element receives and combines into a combined wavefront an object wavefront from an object and a reference wavefront. A wavefront-splitting element splits the combined wavefront into a plurality of sub-wavefronts in such a way that each of the sub-wavefronts is substantially contiguous with at least one other sub-wavefront. The wavefront-splitting element may shift...

The present invention features an anamorphic apparatus that alters a wavefront of a beam having a wavefront error to form a beam comprising a region having a greatly reduced wavefront error. A beam stop may be used with the anamorphic apparatus to define a portion of the region having a greatly reduced wavefront error that is subsequently detected or launched into a fiber optic. Furthermore, the anamorphic apparatus can be incorporated into an interferometry system to reduce errors associated wi...

The disclosure relates to measuring devices that are particularly suited for the purpose of in-situ characterization of particles present in fluid substances or in air using a low-coherence interferometer. Specifically, the characterization includes average size, size distribution, volumetric density, and composition. The low-coherence interferometer utilizes a split band of radiation to illuminate a sample probe and a reference probe then combines the reflected radiation from both probes to det...

Disclosed are first and second embodiments of a 3-channel probe-plate structure of the fiber-optic interferometer, wherein low-coherent-length light from a superluminescent light-emitting diode is split by a tree splitter into three light branches which are coupled as separate light inputs to the probe-pate structure by single-mode, polarization-preserving optical fibers. For each of the 3 channels, the first embodiment of the probe-plate structure comprises an integrated polarizing lithium-niob...

An interferometer spectrometer that has reduced alignment sensitivity is described herein. Parallelism of an output ray pair formed by a single input ray is not affected by variations in relative alignment of the components. In comparison to other compensated interferometer designs, lateral separation errors in the output ray pair due to optical component misalignment are reduced. The reduced alignment sensitivity may be accomplished by utilizing simple planar components that are common to both ...

A lens meter is provided which includes a light source portion which emits measuring light having at least three different wavelengths; a light receiving portion which receives the measuring light which has passed through a to-be-inspected lens immersed in a liquid as a medium; an in-medium optical characteristic measuring device for measuring an optical characteristic of the lens in the medium about each wavelength, based on a deviated quantity of the measuring light detected by the light recei...

An optical pickup apparatus includes first and second light sources which selectively emit one of first and second light beams, the first and second light beams being different in wavelength, the wavelengths of the first and second light beams being appropriate for accessing first and second optical disks respectively. A coupling lens converts a corresponding one of the first and second light beams into a collimated beam. An objective lens forms a light spot on a corresponding one of the first a...

A test device for bodily fluids comprising a solid carrier with a bonded reagent, a light source and a light detector. Light source and light detector are positioned is such a way that the majority of the light travels within the porous body along a transmission path, which is determined by scattering or reflection of the light within the porous body, until it arrives at the exit end where the transmitted light is measured.

A non-contact method for determining the index of refraction or dielectric constant of a thin film on a substrate at a desired frequency in the GHz to THz range having a corresponding wavelength larger than the thickness of the thin film (which may be only a few microns). The method comprises impinging the desired-frequency beam in free space upon the thin film on the substrate and measuring the measured phase change and the measured field reflectance from the reflected beam for a plurality of i...