Abstract:
An imaging device for biochemical or medical samples, the pulse mode light source of which incorporates flash lamps and a rotating mirror in an inclined position, the said mirror reflecting the light emitted by each flash lamp in turn along the same optical path to the sample. The flash lamps are switched on alternately in phases and synchronised with the rotating mirror and the emission light chopper, which comprises two rotating discs. The turning mirror directs the light at the sample from above and/or below, in which case a double-acting transparent scattering plate can be used.
Abstract:
A method of monitoring a time-varying fluorescence emitted from a fluorescent agent from within a diffuse reflecting medium with time-varying optical properties is disclosed that includes providing at least two measurements obtained from a patient before and after administration of the fluorescent agent that includes an Flrmeas signal detected adjacent to the medium by a filtered light detector during illumination of the medium by excitatory-wavelength light, and at least one DR signal selected from: a DRexmeas DRem, and DRem,filtered signal. The method further includes identifying a post-equilibration portion of the measurement data set and transforming each Flrmeas signal within the post-equilibration portion of the measurement data set to an IFagent signal representing a detected fluorescence intensity emitted solely by the fluorescent agent from within the medium. The disclosed method includes removing the effects of leak-through of excitation-level light and removing the effects of autofluorescence from the Flrmeas signal.
Abstract:
Optopair for use in sensors and analyzers of gases such as methane, and a fabrication method therefor is disclosed. It comprises: a) an LED, either cascaded or not, having at least one radiation emitting area, whose spectral maximum is de-tuned from the maximum absorption spectrum line of the gas absorption spectral band; and b) a Photodetector, whose responsivity spectral maximum can be either de-tuned from, or alternatively completely correspond to the maximum absorption spectrum line of the absorption spectral band of the gas. Modeling the LED emission and Photodetector responsivity spectra and minimizing the temperature sensitivity of the optopair based on the technical requirements of the optopair signal registration circuitry, once the spectral characteristics of the LED and Photodetector materials and the temperature dependencies of said spectral characteristics are determined, provides the LED de-tuned emission and Photodetector responsivity target peaks respectively.
Abstract:
A multi-channel source assembly for downhole spectroscopy has individual sources that generate optical signals across a spectral range of wavelengths. A combining assembly optically combines the generated signals into a combined signal and a routing assembly that splits the combined signal into a reference channel and a measurement channel. Control circuitry electrically coupled to the sources modulates each of the sources at unique or independent frequencies during operation.
Abstract:
A cavity ring down system is optimized to precisely measure trace gases or particles in an air sample by using time sampling detection and multiple-sample averaging resulting in a high signal-to-noise ratio. In one embodiment, a cavity ring down system is programmed to measure the rise time and the fall time of the light level in an optical cavity. The cavity ring down system is programmed to integrate a plurality of sample portions during a rise time and a plurality of sample portions during a fall time (in alternate intervals) to obtain a time constant with no sample present and a time constant with sample present. The measurements are used to calculate trace gases in the air sample.
Abstract:
The invention relates to a device and method for monitoring a chemical reaction proceeding from a first state to a second state by emitting and detecting radiation in ranges of interest for a spectral signature of the material undergoing the chemical reaction. Using the concept of optical spectral detection and identification, it is therefore possible to utilize a combination of specific emitters and detectors, optics and signal processing in order to identify materials and events.
Abstract:
A particulate detector (10) comprises a radiation source (12) arranged to emit radiation in at least first and second predetermined wavebands towards a sampling region (18) suspected of containing particulates, and a detection element (14), shielded from the radiation source (12), and arranged to detect radiation from the sampling region (18) at least first and second instances. The radiation source (12) is such that the emissions in the wavebands temporarily overlap. The detector is such that, at the instances at which the radiation is detected, the relative contributions from the emissions in each predetermined waveband are distinguishable, thereby allowing characteristics of the particulates to be determined. The radiation source (12) may comprise a light emitting diode (24).
Abstract:
A detection system is provided, the detection system comprising a light source that generates excitation light having a wavelength sufficient to excite a fluorophore in a sample; an excitation filter positioned along a first line along a path of the excitation light, the excitation filter transmitting the excitation light from the light source; a beam splitter positioned along the first line, the beam splitter reflecting the excitation light transmitted by the excitation filter along a second line toward a mirror positioned on one side of the beam splitter, and passing emitted light reflected along the second line; the mirror, positioned to reflect the excitation light from the beam splitter to the fluorophore in the sample along a third line, normal to both the first and second lines, wherein the mirror further reflects emitted light emitted along the third line, along the second line toward the beam splitter; an emission filter positioned along the second line, on a second side of the beam splitter; and a detector that detects the emitted light transmitted by the emission filter.
Abstract:
An optoelectronic device for measuring the water content in a plant element and an apparatus designed to evaluate and monitor in real time the state of hydration of the plant covers. The device includes an optoelectronic probe connected to a measurement module, the probe including: i) a first light source emitting at a wavelength corresponding to a strong water absorption band; ii) optionally, a second light source emitting at a wavelength close to the first source and weakly absorbed by water; and iii) a photo receiver having a spectral response that corresponds to the emission bands of the first light source or of the first and second light sources, the device including elements for modulating the average optical power emitted by the light source or sources at a defined frequency, and elements for synchronously detecting the light received by the photoreceiver.
Abstract:
An analyte sensor is described. The sensor employs a single sensor element which provides a plurality of phase outputs in response to excitation by a modulated excitation source. The plurality of phase outputs may be analysed to provide information on the presence of one or more analytes.