Abstract: A system for producing single-frequency or near-single-frequency operation of a laser beam includes a laser for emitting a laser beam at each one of a plurality of cavity lengths, A detector is configured to receive at least a portion of the laser beam emitted, and generate a signal. A computer system is configured to identify at least one beat note in the signal for each of at least one of the plurality of cavity lengths, the at least one beat note indicating the presence of one or more higher-order transverse modes, longitudinal modes, or both, in the received at least the portion of the laser beam emitted at the at least one of the plurality of cavity lengths. The cavity is adjusted to one of the plurality of cavity lengths for eliminating or minimizing the at least one beat note.

Abstract: A system for producing single-frequency or near-single-frequency operation of a laser beam includes a laser for emitting a laser beam at each one of a plurality of cavity lengths, A detector is configured to receive at least a portion of the laser beam emitted, and generate a signal. A computer system is configured to identify at least one beat note in the signal for each of at least one of the plurality of cavity lengths, the at least one beat note indicating the presence of one or more higher-order transverse modes, longitudinal modes, or both, in the received at least the portion of the laser beam emitted at the at least one of the plurality of cavity lengths. The cavity is adjusted to one of the plurality of cavity lengths for eliminating or minimizing the at least one beat note.

Abstract: An apparatus for collecting volatile organic compounds from a gas sample such as alveolar breath or room air comprises an exhaust portion having at least a flow measuring device, and a discriminating device for distinguishing between alveolar and non-alveolar breath. The apparatus further comprises a collection portion distinct from and parallel with the exhaust portion having at least a collection component for receiving and concentrating gas samples within a collection chamber and a sampling component having a plurality of sampling devices for receiving the concentrated gas sample from the collection chamber and isolating VOCs contained in the gas sample. The collection chamber is compressible via a drive mechanism for precisely actuating the chamber to draw a gas sample into the collection chamber and circulating the sample to the sampling devices. Use of a drive mechanism enables the exhaust portion to be distinct from the collection portion, thereby mitigating cross-contamination therebetween.

Abstract: An apparatus for collecting volatile organic compounds from a gas sample such as alveolar breath or room air comprises an exhaust portion having at least a flow measuring device, and a discriminating device for distinguishing between alveolar and non-alveolar breath. The apparatus further comprises a collection portion distinct from and parallel with the exhaust portion having at least a collection component for receiving and concentrating gas samples within a collection chamber and a sampling component having a plurality of sampling devices for receiving the concentrated gas sample from the collection chamber and isolating VOCs contained in the gas sample. The collection chamber is compressible via a drive mechanism for precisely actuating the chamber to draw a gas sample into the collection chamber and circulating the sample to the sampling devices. Use of a drive mechanism enables the exhaust portion to be distinct from the collection portion, thereby mitigating cross-contamination therebetween.

Abstract: A system for producing single-frequency or near-single-frequency operation of a laser beam includes a laser for emitting a laser beam at each one of a plurality of cavity lengths, A detector is configured to receive at least a portion of the laser beam emitted, and generate a signal. A computer system is configured to identify at least one beat note in the signal for each of at least one of the plurality of cavity lengths, the at least one beat note indicating the presence of one or more higher-order transverse modes, longitudinal modes, or both, in the received at least the portion of the laser beam emitted at the at least one of the plurality of cavity lengths. The cavity is adjusted to one of the plurality of cavity lengths for eliminating or minimizing the at least one beat note.

Abstract: A method and system for obtaining single-frequency operation of a laser system. A laser beam is emitted from a laser cavity, having an adjustable length, at a plurality of cavity lengths. At least a portion of the laser beam is received at a detector, which detects the presence of transverse and/or longitudinal modes in the laser beam, and generates a laser beam signal having a beat-note indicative thereof. The laser beam signal for each of the plurality of cavity lengths can be analyzed, and a cavity length of best mode purity, indicating single-frequency operation, can be selected. The laser beam system can emit a laser and have a laser beam splitter for directing at least a portion of the emitted laser beam to a laser beam detector for generating at least one laser beam signal therefrom, and an actuator for adjusting the length of the laser cavity.

Abstract: A method and system for obtaining single-frequency operation of a laser system. A laser beam is emitted from a laser cavity, having an adjustable length, at a plurality of cavity lengths. At least a portion of the laser beam is received at a detector, which detects the presence of transverse and/or longitudinal modes in the laser beam, and generates a laser beam signal having a beat-note indicative thereof. The laser beam signal for each of the plurality of cavity lengths can be analyzed, and a cavity length of best mode purity, indicating single-frequency operation, can be selected. The laser beam system can emit a laser and have a laser beam splitter for directing at least a portion of the emitted laser beam to a laser beam detector for generating at least one laser beam signal therefrom, and an actuator for adjusting the length of the laser cavity.

Abstract: An apparatus for collecting volatile organic compounds from a gas sample such as alveolar breath or room air comprises an exhaust portion having at least a flow measuring device, and a discriminating device for distinguishing between alveolar and non-alveolar breath. The apparatus further comprises a collection portion distinct from and parallel with the exhaust portion having at least a collection component for receiving and concentrating gas samples within a collection chamber and a sampling component having a plurality of sampling devices for receiving the concentrated gas sample from the collection chamber and isolating VOCs contained in the gas sample. The collection chamber is compressible via a drive mechanism for precisely actuating the chamber to draw a gas sample into the collection chamber and circulating the sample to the sampling devices. Use of a drive mechanism enables the exhaust portion to be distinct from the collection portion, thereby mitigating cross-contamination therebetween.

Abstract: An apparatus for collecting volatile compounds in human breath. The apparatus includes a device for discriminating between alveolar and non-alveolar portions of exhaled breath, a device for measuring volume of exhaled breath, a chamber with a piston or similar compressible device with clean internal services designed to collect a precise volume of alveolar breath, a pump to draw the exhaled breath from the chamber through at least one sorbent tube, a subsystem for introducing a clean gas into the chamber to expand it and for purging the tubing of the system, and a subsystem for selectively collecting a room air sample. A manifold is provided in the apparatus for receiving sorbent tubes and comprises an input block and output block, and a locking lever for actuating the input and output blocks linearly towards and away from each other and selectively locking them in a fully closed position.

Abstract: An apparatus for collecting volatile compounds in human breath includes a device for discriminating between alveolar and non-alveolar portions of exhaled breath by real-time measurement of a physical characteristic of said exhaled breath; a device for measuring volume of exhaled breath; a chamber with piston or similar compressible device with clean internal surfaces designed to collect a precise volume of the alveolar portion of the exhaled breath; a pump to draw the exhaled breath collected in the chamber through at least one sorbent tube; a subsystem for introducing a clean compressed gas into the chamber to expand it, and for purging the internal tubing of the system; and a subsystem for selectively collecting a room air sample.