Optical spectroscopy apparatus and method for measurement of analyte concentrations or other such species in a specimen employing a semiconductor laser-pumped, small-cavity fiber laser
First Claim
1. An optical spectroscopy apparatus for determining the concentration of analyte in a specimen that utilizes a radiation source comprising at least one combination of a semiconductor pump laser and small-cavity fiber laser where laser cavities of both lasers are butt coupled to provide a plurality of laser cavities that produce a plurality of emission wavelengths at a same output of the butt coupled laser that are designed to substantially match distinguishing spectral characteristic features along at least a portion of an characteristic optical spectrum of the analyte under determination.
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Abstract
An optical spectroscopy apparatus determines the concentration of analyte in a specimen that utilizes a single radiation source which is hybrid laser comprising a semiconductor pump laser and small-cavity rare earth fiber laser where laser cavities of both lasers are butt coupled or otherwise optically coupled to form a plurality of laser cavities that produce a plurality of emission wavelengths, one which may be the pump laser emission wavelength at the output of the fiber laser thereby forming a multi-wavelength combined output where the wavelengths substantially match distinguishing spectral characteristic features along at least a portion of a characteristic optical spectrum of the analyte under examination. In lieu of complex data analysis of these wavelengths to determine values representing the concentration of the analyte in an examined specimen, the semiconductor pump laser or lasers are modulated as a plurality of tone frequencies, where at least a first of the modulation frequencies is below the maximum frequency response of the fiber laser so that the first modulation effectively modulates the pump emission wavelength and a first emission wavelength of the fiber laser in the hybrid laser combined output, and at least a second of modulation frequencies is above the maximum frequency response of the fiber laser so that the second modulation effectively modulates the pump emission wavelength but not the first emission wavelength of the fiber laser in the hybrid laser combined output. Further, one or more additional modulation frequencies may be applied to the pump laser which are intermediate of the first and second modulation frequencies where it is at least responsive to at least one further emission wavelength of the fiber laser and also provided in the hybrid laser combined output.
165 Citations
91 Claims
- 1. An optical spectroscopy apparatus for determining the concentration of analyte in a specimen that utilizes a radiation source comprising at least one combination of a semiconductor pump laser and small-cavity fiber laser where laser cavities of both lasers are butt coupled to provide a plurality of laser cavities that produce a plurality of emission wavelengths at a same output of the butt coupled laser that are designed to substantially match distinguishing spectral characteristic features along at least a portion of an characteristic optical spectrum of the analyte under determination.
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17. The optical spectroscopy apparatus of claim 17 wherein said fiber material is ZBLAN.
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33. An optical spectroscopy apparatus for determining the concentration of analyte in a specimen, comprising:
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a hybrid laser that includes a semiconductor pump laser with a small-cavity fiber laser having a plurality of laser cavities that provide at an output from the hybrid laser a plurality of different emission wavelengths of radiation at least one from the small-cavity fiber laser and another from the semiconductor pump laser that substantially match distinguishing wavelength spectral characteristic features along at least a portion of an absorption spectral range of the analyte;
means for modulating the hybrid laser with a plurality of tone frequencies where all the tone frequencies effectively modulate an emission wavelength from the semiconductor laser and at least one tone frequency effectively modulates an emission wavelength from the fiber laser;
means for collecting the modulated radiation from the hybrid laser output reflected from or passed through the specimen containing the analyte under examination;
means for sensing the modulated tone frequencies from the collected radiation wavelengths producing a plurality of tone frequencies representative of amplitude absorption values at the absorption intensity wavelength spectral characteristic features of the analyte within the absorption spectral portion;
means for comparing the sensed tone frequencies with a set of corresponding tone frequencies absent of the spectral absorption from the analyte producing a set of values representative of spectral characteristic features after spectral absorption by the analyte; and
means for correlating differences in the set of values to produce a final value representative of a measurement of concentration of the analyte in the specimen. - View Dependent Claims (34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44)
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- 45. An optical spectroscopy apparatus for determining the concentration of an analyte in a specimen, comprising a radiation source comprising a hybrid laser having a semiconductor pump laser optically coupled to a small-cavity fiber laser doped with a rare earth species and produces a plurality of emission wavelengths at a single output at two or more emission wavelengths from said hybrid laser where all of said wavelengths substantially match distinguishing spectral characteristic features along at least a portion of an absorption spectral range of the analyte under examination.
- 57. A hybrid laser comprising a first laser optically coupled to second laser and having a single output, said first laser responsive to a plurality of applied tone frequencies and said second laser is responsive to modulation at not all of said tone frequencies.
- 68. A hybrid laser comprising a first laser optically coupled to second laser and having a single output, said first laser responsive to a plurality of applied tone frequencies, said second laser has a maximum frequency response, at least one of said tone frequencies is below said maximum frequency response.
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79. A method of determining the concentration of an analyte in a specimen comprising the steps of:
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providing a hybrid laser that has multiple separate lasing cavities for producing at an output a plurality of emission wavelengths that substantially match distinguishing wavelength spectral characteristic features along at least a portion of a characteristic optical spectrum of the analyte; and
modulating one of said lasing cavities with a plurality of tone frequencies where some of said output emission wavelengths are modulated by the tone frequencies in one of said lasing cavities but at least one other of said output emission wavelengths is not modulated by at least one of said tone frequencies in the other of said lasing cavities. - View Dependent Claims (80, 81, 82)
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83. A method of determining the concentration of an analyte in a specimen comprising the steps of:
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providing a hybrid laser that comprises a first and second laser for producing at a single output a plurality of emission wavelengths that substantially match distinguishing wavelength spectral characteristic features along at least a portion of a characteristic optical spectrum of the analyte;
modulating the first laser with a plurality of tone frequencies where at least one of said tone frequencies is above a maximum frequency response of the second laser so that at least one emission wavelength from the second laser is not modulated by a tone frequency;
applying the modulated output emission wavelengths to the specimen under examination;
collecting radiation reflected, scattered or passed through the specimen;
comparing the modulated frequencies of radiation before the step of applying with the modulated frequencies with those after the step of collecting to produce a set of values representative of wavelength spectral characteristic features of the analyte within the characteristic optical spectrum portion; and
correlating differences in the set of values to produce a final value representative of a measurement of concentration of the analyte in the specimen. - View Dependent Claims (84, 85, 86, 87, 88, 89, 90, 91)
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Specification