Abstract:
A compact, lightweight, portable optical assembly comprising: a platform; and a plurality of optical elements mounted to the platform; wherein the plurality of optical elements are optically connected to one another with free-space couplings so as to form an optical circuit; and further wherein the platform is sufficiently mechanically robust so as to maintain the free-space optical coupling between the various optical elements. A method for making a compact, lightweight, portable optical assembly, comprising: providing a platform; and mounting a plurality of optical elements to the platform; wherein the plurality of optical elements are mounted to the platform so that they are optically connected to one another with free-space couplings so as to form an optical circuit; and further wherein the platform is sufficiently mechanically robust so as to maintain the free-space optical coupling between the various optical elements.
Abstract:
An LED-based color measurement instrument including an illumination system and a sensing system. The illumination system includes modulated LEDs and a temperature control system for regulating the temperature of the LEDs, thereby improving the consistency of their performance. The sensing system includes a photodiode, a transimpedance amplifier, and an integrator in the first stage to cancel the effect of ambient light on the output of the first stage. The sensing system also includes a lens system for imaging a target area of the target sample onto the photo sensor in a manner so that the product of the target area times the solid angle captured by the lens system is generally uniform over a selected range of distances, thereby reducing the positional sensitivity of the instrument with respect to the target sample.
Abstract:
The invention relates to a device for measuring light-activated fluorescence of at least one coating that contains a fluorescent material, and its use for measuring fluid materials which cause fluorescence-quenching in at least one of the fluorescent coatings. To activate the fluorescence, at least one first light wave-guide is directed onto at least one coating applied to a support and the fluorescent light is directed at a detector by means of at least one-second light wave-guide, in order to determine the intensity of the fluorescent light. The end faces of the different fluorescent light wave guides are then arranged to have overlapping entry and/or exit cones and/or be of a shape substantially identical to the at least one coating containing a fluorescent material, in such a way that an accurate measurement of the fluorescence intensity can be attained, and that the light source(s), light wave guides and the detector(s) are lodged in a measuring head.
Abstract:
An infrared spectrometer is described wherein a detector array is optically coupled to a slab waveguide structure. A focal plane is provided outside of the output face of the slab waveguide structure and the detector array is mounted onto the slab waveguide structure at a fixed distance from the output face on the output focal plane.
Abstract:
A spectrometer comprising a collimating element for receiving input light and collimating the same, a dispersive optical element for receiving light from the collimating element and dispersing the same and a focusing element for receiving light from the dispersive optical element and focusing the same on a detector assembly wherein, where the wavelength dispersion of the dispersed light extends in the x-y direction, the collimating element and the focusing element are formed so as to maintain the desired optical parameters in the x-y plane while having a reduced size in the z direction.
Abstract:
An optical instrument including: a thermo-optically tunable, thin film, free-space interference filter having a tunable passband which functions as a wavelength selector, the filter including a sequence of alternating layers of amorphous silicon and a dielectric material deposited one on top of the other and forming a Fabry-Perot cavity structure having: a first multi-layer thin film interference structure forming a first mirror; a thin-film spacer layer deposited on top of the first multi-layer interference structure, the thin-film spacer layer made of amorphous silicon; and a second multi-layer thin film interference structure deposited on top of the thin-film spacer layer and forming a second mirror; a lens for coupling an optical beam into the filter; an optical detector for receiving the optical beam after the optical beam has interacted with the interference filter; and circuitry for heating the thermo-optically tunable interference filter to control a location of the passband.
Abstract:
A field test-kit for analyzing arsenic concentration in water samples is provided. The kit includes a portable infrared beam photometer for measuring light absorbance in aqueous specimens. An infrared light emitting diode is configured to direct a beam of light through a specimen. A photodetector diode measures the intensity of light passing through the specimen. The photodetector output voltages relate to the light absorbed in the specimen and are displayed on a liquid crystal display screen. The kit is assembled using off-the-shelf electronic and opto-electronic components that have low power requirements. Dry cell batteries or solar cells power the kit. To test for arsenic, molybdenum based chemistries are used to selectively bind and convert arsenates and phosphates in the specimen into molybdenum-blue color complexes. The light absorbance of a specimen with both arsenates and phosphates bound in molybdenum-blue color complexes is compared to that of a reference specimen in which phosphates but not arsenates are bound and converted. The differential light absorbance of the two specimens is used to arrive at a quantitative value for the arsenic concentration in the water sample.
Abstract:
The invention provides a method for stabilizing a spectrometric transducer for an optical spectrum measuring instrument by obtaining an instantaneous central wavelength of a thermally controlled tunable filter of the instrument, calibrating for a selected ambient temperature, determining a heat variance of the filter and controlling the filter to compensate for heat variance.
Abstract:
A device and method are provided for use with a noninvasive optical measurement system, such as a thermal gradient spectrometer, for improved determination of analyte concentrations within living tissue. In one embodiment, a wearable window is secured to a patient's forearm thereby isolating a measurement site on the patient's skin for determination of blood glucose levels. The wearable window effectively replaces a window of the spectrometer, and thus forms an interface between the patient's skin and a thermal mass window of the spectrometer. When the spectrometer must be temporarily removed from the patient's skin, such as to allow the patient mobility, the wearable window is left secured to the forearm so as to maintain a consistent measurement site on the skin. When the spectrometer is later reattached to the patient, the wearable window will again form an interface between the spectrometer and the same location of skin as before.
Abstract:
The present invention provides a diffraction grating element that allows the temperature control mechanism to be dispensed with or simplified. The diffraction grating element of the present invention comprises a transparent plate having a first surface and a second surface that are substantially parallel with one another; and a diffraction grating which is formed on a first surface side with respect to the second surface and is substantially parallel with the first surface. At any temperature within a temperature range −20° C. to +80° C., the sum of the rate of change in the period per unit length of the diffraction grating with respect to a temperature change, and the temperature coefficient of the refractive index of a medium that surrounds the diffraction grating element is 0.