Evanescent-wave quartz-enhanced photoacoustic sensor with resonator elements
First Claim
1. An evanescent-wave quartz enhanced microfiber photoacoustic detection device with oscillator and micro-resonator elements for detecting trace gas concentrations, the evanescent-wave quartz enhanced microfiber photoacoustic detection device comprising:
- a light source tuned to a wavelength corresponding to the optical absorption of a gas to be detected;
an optical fiber;
a fiber-taper to generate an evanescent wave, a coating layer of the fiber-taper being stripped;
a quartz tuning fork having its free arms arranged at the level of the fiber-taper to absorb a mechanical force generated following the optical absorption by the gas, the mechanical forceexciting a piezoelectric mode of the quartz tuning fork and generating an electrical current;
a micro-resonator disposed adjacent to the quartz tuning fork and configured to enhance the mechanical force;
a transimpedance amplifier amplifying a current generated by the quartz tuning fork to determine the concentration of the gas; and
a lock-in amplifier directly connected to the transimpedance amplifier,wherein the fiber-taper, quartz tuning fork, and micro-resonator are assembled in a sealed gas cell for gas detection.
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Abstract
A novel evanescent-wave quartz-enhanced optical microfiber photoacoustic gas sensor is provided for detecting trace amounts of gas. Both fiber-taper based evanescent field and photoacoustic spectroscopy can be used to exploit the merits of both technologies. The use of a fiber half-taper into the tuning fork and microresonator tubes can result in reduced system size, simplified optical alignment, and high sensitivity. The techniques described can be used in chemical, biological and environmental sensing applications.
11 Citations
16 Claims
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1. An evanescent-wave quartz enhanced microfiber photoacoustic detection device with oscillator and micro-resonator elements for detecting trace gas concentrations, the evanescent-wave quartz enhanced microfiber photoacoustic detection device comprising:
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a light source tuned to a wavelength corresponding to the optical absorption of a gas to be detected; an optical fiber; a fiber-taper to generate an evanescent wave, a coating layer of the fiber-taper being stripped; a quartz tuning fork having its free arms arranged at the level of the fiber-taper to absorb a mechanical force generated following the optical absorption by the gas, the mechanical force exciting a piezoelectric mode of the quartz tuning fork and generating an electrical current; a micro-resonator disposed adjacent to the quartz tuning fork and configured to enhance the mechanical force; a transimpedance amplifier amplifying a current generated by the quartz tuning fork to determine the concentration of the gas; and a lock-in amplifier directly connected to the transimpedance amplifier, wherein the fiber-taper, quartz tuning fork, and micro-resonator are assembled in a sealed gas cell for gas detection. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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Specification