Abstract: We present here systems and methods for generating a heterodyne signal using the naturally occurring chirp of a pulsed single-mode laser. The electrical square-wave pulse used to drive the laser heats the laser cavity, causing the laser frequency to change or chirp during the emission of the optical pulse. This chirped optical pulse can be split into a chirped signal pulse that interacts with a sample and a chirped reference pulse that interferes with the chirped signal pulse on a detector to produce a heterodyne modulation whose instantaneous phase and amplitude depend on the sample's dispersion and absorption, respectively. The chirp is reproducible, so the heterodyne modulation, instantaneous phase, and/or instantaneous amplitude can be average over many measurements, either with multiple pulses from the same laser or multiple pulses from different lasers, each emitting at a different wavelength.

Abstract: We present here systems and methods for generating a heterodyne signal using the naturally occurring chirp of a pulsed single-mode laser. The electrical square-wave pulse used to drive the laser heats the laser cavity, causing the laser frequency to change or chirp during the emission of the optical pulse. This chirped optical pulse can be split into a chirped signal pulse that interacts with a sample and a chirped reference pulse that interferes with the chirped signal pulse on a detector to produce a heterodyne modulation whose instantaneous phase and amplitude depend on the sample's dispersion and absorption, respectively. The chirp is reproducible, so the heterodyne modulation, instantaneous phase, and/or instantaneous amplitude can be average over many measurements, either with multiple pulses from the same laser or multiple pulses from different lasers, each emitting at a different wavelength.

Abstract: We present here systems and methods for generating a heterodyne signal using the naturally occurring chirp of a pulsed single-mode laser. The electrical square-wave pulse used to drive the laser heats the laser cavity, causing the laser frequency to change or chirp during the emission of the optical pulse. This chirped optical pulse can be split into a chirped signal pulse that interacts with a sample and a chirped reference pulse that interferes with the chirped signal pulse on a detector to produce a heterodyne modulation whose instantaneous phase and amplitude depend on the sample's dispersion and absorption, respectively. The chirp is reproducible, so the heterodyne modulation, instantaneous phase, and/or instantaneous amplitude can be average over many measurements, either with multiple pulses from the same laser or multiple pulses from different lasers, each emitting at a different wavelength.

Abstract: In quartz-enhanced photoacoustic spectroscopy (QEPAS), an analyte (typically in gas phase) generates a pressure wave in response to incident laser light. A quartz tuning fork (QTF) resonant at the frequency of the pressure wave transduces the pressure wave into an electrical signal. Pulsing the laser briefly reduces the amount of thermal chirp and increases the fraction of time that the laser emits at the wavelength(s) of interest. This increases the measurement efficiency. Pulsing the incident laser light with bursts of short pulses at the QTF resonant frequency increases signal strength. Exciting the sample with a two pulses at different laser wavelengths, separated by a half QTF period yields signal and background acoustic waves that partially cancel when integrated by the QTF, producing a differential measurement. Pulsing the incident laser light at a frequency faster than the gas response cut off frequency can improve the noise performance of a QEPAS measurement.

Abstract: Disclosed herein are methods and systems for scanning objects and associated substances, where the methods include: (a) using a first electronic device to scan a feature of an object and provide reference information about the object based on the scanned feature, where the feature identifies the object or a substance associated with the object; (b) using a second electronic device to measure electromagnetic radiation emitted from the object and provide sample information about the object based on the measured electromagnetic radiation; and (c) comparing the sample information and the reference information to determine whether the object includes the substance associated with the object.

Abstract: Systems and methods disclosed include: a support apparatus configured to detachably receive a chip; movable pins extendible from a first position to a second position, where, in the first position, the movable pins do not contact a chip positioned on the support apparatus, and in the second position, the movable pins contact electrical terminals of a heating element within a chip positioned on the support apparatus; a radiation source configured to direct radiation to be incident on a chip positioned on the support apparatus; a detector; and an electronic processor, the electronic processor being configured to detect molecules in a sample positioned within the chip, and to determine a temperature of the chip by measuring an electrical resistance between two of the multiple pins connected to the electrical terminals.

Abstract: Disclosed herein are methods and systems for scanning objects and associated substances, where the methods include: (a) using a first electronic device to scan a feature of an object and provide reference information about the object based on the scanned feature, where the feature identifies the object or a substance associated with the object; (b) using a second electronic device to measure electromagnetic radiation emitted from the object and provide sample information about the object based on the measured electromagnetic radiation; and (c) comparing the sample information and the reference information to determine whether the object includes the substance associated with the object.

Abstract: We disclose apparatus that includes: (a) an enclosure including an aperture; (b) a prism mounted in the enclosure so that a surface of the prism is exposed through the aperture; (c) an optical assembly contained within the enclosure, the optical assembly including a radiation source and a radiation detector, the source being configured to direct radiation towards the prism and the detector being configured to detect radiation from the source reflected from the exposed surface of the prism; and (d) an electronic processor contained within the enclosure, the electronic processor being in communication with the detector. The apparatus can be configured so that, during operation, the electronic processor determines information about a sample placed in contact with the exposed surface of the prism based on radiation reflected from the exposed prism surface while it is in contact with the sample.

Abstract: We disclose an apparatus comprising: a hand-portable optical analysis unit including an optical interface; and a device configured to receive and releasably engage the hand-portable optical analysis unit. The device comprises: a housing; a sample unit in the housing; and a resilient member configured to bias the sample unit and the hand-portable analysis unit towards each other when the hand-portable optical analysis unit is received in the device to compress a sample disposed between the sample unit and the optical interface of the optical analysis unit. Methods of analyzing samples are also disclosed.

Abstract: The apparatus disclosed herein features: (a) a handheld, portable spectrometer that includes a radiation source configured to direct incident radiation to a sample, a detector configured to receive signal radiation from the sample, and a housing enclosing the radiation source and the detector; (b) an extended member attachable to the housing and having an interior channel to define a path for directing radiation from the source to the sample and for receiving radiation from the sample at the detector; (c) and a vial receptacle configured to hold a different sample and positioned to receive radiation from the source, where the detector is positioned to receive radiation from the different sample and the housing is configured to support the vial receptacle and attach to the extended member at the same time.

Abstract: We disclose apparatus that includes: (a) an enclosure including an aperture; (b) a prism mounted in the enclosure so that a surface of the prism is exposed through the aperture; (c) an optical assembly contained within the enclosure, the optical assembly including a radiation source and a radiation detector, the source being configured to direct radiation towards the prism and the detector being configured to detect radiation from the source reflected from the exposed surface of the prism; and (d) an electronic processor contained within the enclosure, the electronic processor being in communication with the detector. The apparatus can be configured so that, during operation, the electronic processor determines information about a sample placed in contact with the exposed surface of the prism based on radiation reflected from the exposed prism surface while it is in contact with the sample.

Abstract: We disclose an apparatus comprising: a hand-portable optical analysis unit including an optical interface; and a device configured to receive and releasably engage the hand-portable optical analysis unit. The device comprises: a housing; a sample unit in the housing; and a resilient member configured to bias the sample unit and the hand-portable analysis unit towards each other when the hand-portable optical analysis unit is received in the device to compress a sample disposed between the sample unit and the optical interface of the optical analysis unit. Methods of analyzing samples are also disclosed.

Abstract: We disclose apparatus that includes: (a) an enclosure including an aperture; (b) a prism mounted in the enclosure so that a surface of the prism is exposed through the aperture; (c) an optical assembly contained within the enclosure, the optical assembly including a radiation source and a radiation detector, the source being configured to direct radiation towards the prism and the detector being configured to detect radiation from the source reflected from the exposed surface of the prism; and (d) an electronic processor contained within the enclosure, the electronic processor being in communication with the detector. The apparatus can be configured so that, during operation, the electronic processor determines information about a sample placed in contact with the exposed surface of the prism based on radiation reflected from the exposed prism surface while it is in contact with the sample.

Abstract: Systems and methods disclosed include: a support apparatus configured to detachably receive a chip; movable pins extendible from a first position to a second position, where, in the first position, the movable pins do not contact a chip positioned on the support apparatus, and in the second position, the movable pins contact electrical terminals of a heating element within a chip positioned on the support apparatus; a radiation source configured to direct radiation to be incident on a chip positioned on the support apparatus; a detector; and an electronic processor, the electronic processor being configured to detect molecules in a sample positioned within the chip, and to determine a temperature of the chip by measuring an electrical resistance between two of the multiple pins connected to the electrical terminals.

Abstract: A portable device includes a base unit, an extension, and a mirror. The base unit includes a light source, a light detector, and at least one window through which light exits from, and is received by, the base unit. The extension is configured, during use, to be attached to the base unit and to extend from the at least one window, in a direction away from the base unit, the extension defining at least a portion of a sample volume in fluid communication with gases substantially surrounding one or more of the extension and the base unit. The mirror is attached to the extension at a distance from the at least one window. An optical path is defined between the mirror and the at least one window such that light from the light source moves through the sample volume along the optical path, and the mirror is aligned to reflect the light back to the at least one window for detection by the light detector.

Abstract: The present invention provides a novel approach for reliably and accurately detecting and identifying airborne particles. This is done by providing a novel system which incorporates electrostatic concentrators and/or ion mobility separators with Raman, IR, UV, XRF, LIF and LIBS spectroscopy and/or other spectroscopic techniques.

Abstract: An apparatus includes: a handheld Raman analyzer that can include: a common platform; a laser assembly mounted on a laser platform, the laser platform supported on the common platform by a first material and a second thermally conductive material wherein the first material is softer than the second material; an optical probe head assembly disposed on the common platform, the optical probe head assembly spaced apart from the laser assembly; a spectrometer assembly disposed on the common platform, the spectrometer assembly spaced apart from the optical probe head assembly; and an analysis apparatus configured to identify a specimen based on a Raman signature received from the spectrometer. The laser assembly can be optically coupled to the optical probe head assembly by at least a first free-space coupling region and the optical probe head assembly optically coupled to the spectrometer assembly by at least a second free-space coupling region.

Abstract: A laser package comprising a semiconductor laser having an operating temperature range and a heater, wherein the heater is configured to heat the laser when the laser package is positioned in an environment having an ambient temperature which lies outside of the operating temperature range of the laser, so that the laser will remain within the operating temperature range.

Abstract: We disclose apparatus that includes: (a) an enclosure including an aperture; (b) a prism mounted in the enclosure so that a surface of the prism is exposed through the aperture; (c) an optical assembly contained within the enclosure, the optical assembly including a radiation source and a radiation detector, the source being configured to direct radiation towards the prism and the detector being configured to detect radiation from the source reflected from the exposed surface of the prism; and (d) an electronic processor contained within the enclosure, the electronic processor being in communication with the detector. The apparatus can be configured so that, during operation, the electronic processor determines information about a sample placed in contact with the exposed surface of the prism based on radiation reflected from the exposed prism surface while it is in contact with the sample.

Abstract: We disclose apparatus that includes: (a) an enclosure including an aperture; (b) a prism mounted in the enclosure so that a surface of the prism is exposed through the aperture; (c) an optical assembly contained within the enclosure, the optical assembly including a radiation source and a radiation detector, the source being configured to direct radiation towards the prism and the detector being configured to detect radiation from the source reflected from the exposed surface of the prism; and (d) an electronic processor contained within the enclosure, the electronic processor being in communication with the detector. The apparatus can be configured so that, during operation, the electronic processor determines information about a sample placed in contact with the exposed surface of the prism based on radiation reflected from the exposed prism surface while it is in contact with the sample.