Patent•
Methods and devices for analyzing material properties and detecting objects in scattering media
08 Feb 2009-
TL;DR: In this article, a method for determining an phase spectrum of the complex spectral transfer function H(ω) of a medium is presented, which is applied for detecting or imaging an object screened by a scattering medium or for determining a refractive index spectrum of a material.
Abstract: Disclosed is a method for determining an phase spectrum θ(ω) of the complex spectral transfer function H(ω) of a medium. In some embodiments, the method is applied for detecting or imaging an object screened by scattering medium or for determining a refractive index spectrum of a material.
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Patent•
27 Oct 2010TL;DR: In this paper, the authors describe a device for processing a signal delivered by a radiation detector, the device comprising a circuit (2, 3) able to deliver a voltage pulse whose amplitude is proportional to a charge detected by the detector (1) and an analog/digital converter (ADC) which digitizes the voltage pulse and delivers digital signals, characterized in that it comprises, downstream of the ADC, a processing circuit (5) which comprises: - a unit for reading the digital signals (S(t)) delivered by the Analog/Digital Converter (AD
Abstract: The invention relates to a device for processing a signal delivered by a radiation detector (1), the device comprising a circuit (2, 3) able to deliver a voltage pulse whose amplitude is proportional to a charge detected by the detector (1) and an analog/digital converter (ADC) which digitizes the voltage pulse and delivers digital signals, characterized in that it comprises, downstream of the analog/digital converter (ADC), a processing circuit (5) which comprises: - a unit for reading the digital signals (S(t)) delivered by the analog/digital converter (ADC), - a calculation unit which calculates a temporal variation of the digital signals read, and - a circuit able to capture the digital signals read whose temporal variation reaches a predetermined threshold.
25 citations
Patent•
28 Jul 2013
TL;DR: In this paper, an extended broadband light source produces light, and directs the light toward the object, such as to create respective images of the light source on the respective layers of the object.
Abstract: Apparatus and methods are described for optically analyzing an object having a plurality of layers, without needing to use a reference mirror. An extended broadband light source produces light, and directs the light toward the object, such as to create respective images of the light source on the respective layers of the object. An imaging system gathers light that is reflected from a point of the object into a conjugate point in the detector. The detector determines the thicknesses of the plurality of layers at the point of the object by analyzing, within the gathered light, interference between light reflected from the plurality of layers of the object at the point. Other applications are also described.
12 citations
Patent•
27 Jan 2017
TL;DR: A photoacoustic remote sensing system (NI-PARS) for imaging a subsurface structure in a sample, has an excitation beam configured to generate ultrasonic signals in the sample at the excitation location, a portion of the interrogation beam returning from the sample that is indicative of the generated ultrasonic signal as mentioned in this paper.
Abstract: A photoacoustic remote sensing system (NI-PARS) for imaging a subsurface structure in a sample, has an excitation beam configured to generate ultrasonic signals in the sample at an excitation location; an interrogation beam incident on the sample at the excitation location, a portion of the interrogation beam returning from the sample that is indicative of the generated ultrasonic signals; an optical system that focuses at least one of the excitation beam and the interrogation beam with a focal point that is below the surface of the sample; and a detector that detects the returning portion of the interrogation beam.
6 citations
Patent•
06 Mar 2014
TL;DR: In this article, a method for measuring a scintillation property of a sample includes directing an ionizing radiation toward the sample, thereby inducing the sample to produce an emission, and acquiring a spectral luminescence of the produced emission by the sample.
Abstract: Various embodiments of systems, components, modules, routines, and processes for luminescence based spectral measurement are described herein. In one embodiment, a method for measuring a scintillation property of a sample includes directing an ionizing radiation toward the sample, thereby inducing the sample to produce an emission. The method also includes acquiring a spectral luminescence of the produced emission by the sample, the spectral luminescence including a plurality of luminescence intensities at corresponding emission wavelengths or frequencies. The scintillation property of the sample may then be determined based on the acquired spectral luminescence.
4 citations
Patent•
24 Oct 2014
TL;DR: In this paper, a high speed optical chopper is used to periodically interrupt the laser light beam between the laser source and the sample, and a synchronized time-gated optical window is provided for receiving mostly Raman signal while rejecting most or some of the fluorescence signal transmitted from the sample in response to the light beam before reaching the sensor.
Abstract: According to various embodiments, a Raman spectroscopy method is provided for reduction of background fluorescence signal. The method may utilize a high speed optical chopper configured to periodically interrupt the laser light beam between the laser light source and the sample; and using the high speed optical chopper to provide a synchronized time-gated optical window for receiving mostly Raman signal while rejecting most or some of the fluorescence signal transmitted from the sample in response to the laser light beam before reaching the sensor
2 citations
References
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Patent•
23 Jan 2002TL;DR: In this paper, a method and processing device are presented for reconstructing an absorption and/or scattering image of a region of interest inside a scattering medium, where a mathematical model is provided being representative of a relation between the distribution of the intensity and phase of electromagnetic radiation components scattered from a medium and a certain attenuation factor, which is function of spatial variations of scattering and absorption coefficients of the medium.
Abstract: A method and processing device are presented for reconstructing an absorption and/or scattering image of a region of interest inside a scattering medium. A mathematical model is provided being representative of a relation between the distribution of the intensity and phase of electromagnetic radiation components scattered from a medium and a certain attenuation factor, which is function of spatial variations of scattering and absorption coefficients of the medium. The mathematical is used for processing a map of distribution of the intensity of electromagnetic radiation components scattered from known locations within the region of interest, thereby producing a halftone pattern of the region of interest.
34 citations
TL;DR: In this paper, singly subtractive Kramers-kronig (SSKK) relations were proposed to improve the accuracy of data inversion for the moments of arbitrary order harmonic generation susceptibility.
Abstract: We present multiply subtractive Kramers–Kronig (MSKK) relations for the moments of arbitrary order harmonic generation susceptibility. Using experimental data on third-harmonic wave from polysilane, we show that singly subtractive Kramers–Kronig (SSKK) relations provide better accuracy of data inversion than the conventional Kramers–Kronig (KK) relations. The fundamental reason is that SSKK and MSKK relations have strictly faster asymptotic decreasing integrands than the conventional KK relations. Therefore SSKK and MSKK relations can provide a reliable optical data inversion procedure based on the use of measured data only.
17 citations
Patent•
18 Jul 2003TL;DR: In this article, the spectral amplitude and phase measurements are derived from a heterodyne signal, which is produced by combining and mixing the input optical signal and a local oscillator (LO) signal.
Abstract: An optical analyzer and method for measuring optical properties of optical signals utilizes a heterodyne architecture to measure spectral amplitude and phase of a periodically modulated input optical signal, such as an optical signal from a periodically modulated distributed feedback (DFB) laser. The spectral amplitude and phase measurements are derived from a heterodyne signal, which is produced by combining and mixing the input optical signal and a local oscillator (LO) signal. The optical spectrum that is reconstructed from the heterodyne signal includes “inner” spectral peaks that contain phase information of the input optical signal. The inner spectral peaks may be produced by an optical or electrical mixing technique. The spectral phase of the input optical signal is recovered from the inner spectral peaks of the reconstructed optical spectrum.
15 citations
TL;DR: In this paper, the Kramers-Kronig (KK) algorithm is applied to reconstruct the impulse response of a diffusive medium, and it is demonstrated by a simulation of a 1D scattering medium with realistic parameters that its impulse response can be generated from the KK method with high accuracy.
Abstract: The Kramers-Kronig (KK) algorithm, useful for retrieving the phase of a spectrum based on the known spectral amplitude, is applied to reconstruct the impulse response of a diffusive medium. It is demonstrated by a simulation of a 1D scattering medium with realistic parameters that its impulse response can be generated from the KK method with high accuracy.
13 citations
Patent•
07 Mar 2002
TL;DR: In this paper, a method for processing an amplitude modulated (AM) optical beam amplitude with a modulation pattern having an extinction ratio (ER), having a carrier frequency and a carrier amplitude amplitude, is presented.
Abstract: There is therefore provided, in accordance with an embodiment of the present invention, a method for processing an amplitude modulated (AM) optical beam amplitude modulated with a modulation pattern having an extinction ratio (ER), said AM beam having a carrier frequency and a carrier frequency amplitude, the method comprising: estimating an absolute amplitude extremum for the AM beam that is either an absolute amplitude maximum or an absolute amplitude minimum, to which recurrent amplitude extrema of the AM beam are approximately equal; estimating a corresponding phase to which the phase of the AM beam is substantially equal whenever the amplitude of the AM beam is substantially equal to the amplitude extremum; and adjusting at least one of the magnitude and phase of the carrier amplitude of the AM beam responsive to the amplitude extremum and its corresponding phase to increase the extinction ratio of the modulation pattern. The optical processing is carried out in a Brillouin Fiber grating formed by stimulated Brillouin scattering (SBS).
10 citations