Optical-feedback cavity-enhanced absorption spectroscopy in a linear cavity: model and experiments

Manfred, Katherine; Ciaffoni, Luca; Ritchie, Grant A. D.

doi:10.1007/s00340-015-6140-y

Cited by 24 publications

(10 citation statements)

References 38 publications

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“…The OF-CEAS absorption spectrum is obtained within a limited spectral range by scanning the laser emission over hundreds of sequential cavity modes continuously, the recorded mode intensity ( I ) and the corresponding mode intensity without absorption ( I 0 ) are used to calculate the absorption coefficient α . Assuming that absorption of sample gas in a single pass is small compared to mirror losses [26], the OF-CEAS formula is:α=1−RLfalse(I0I−1false), where the effective reflectivity ( R ) is determined by the cavity decay of “empty cavity”.…”

Section: Methodsmentioning

confidence: 99%

Application of Near-Infrared Optical Feedback Cavity Enhanced Absorption Spectroscopy (OF-CEAS) to the Detection of Ammonia in Exhaled Human Breath

Luo

Tan

Long

2019

Sensors

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The qualitative and quantitative analysis to trace gas in exhaled human breath has become a promising technique in biomedical applications such as disease diagnosis and health status monitoring. This paper describes an application of a high spectral resolution optical feedback cavity enhanced absorption spectroscopy (OF-CEAS) for ammonia detection in exhaled human breath, and the main interference of gases such as CO2 and H2O are approximately eliminated at the same time. With appropriate optical feedback, a fibered distributed feedback (DFB) diode laser emitting at 1531.6 nm is locked to the resonance of a V-shaped cavity with a free spectral range (FSR) of 300 MHz and a finesse of 14,610. A minimum detectable absorption coefficient of αmin = 2.3 × 10−9 cm−1 is achieved in a single scan within 5 s, yielding a detection limit of 17 ppb for NH3 in breath gas at low pressure, and this stable system allows the detection limit down to 4.5 ppb when the spectra to be averaged over 16 laser scans. Different from typical CEAS with a static cavity, which is limited by the FSR in frequency space, the attainable spectral resolution of our experimental setup can be up to 0.002 cm−1 owing to the simultaneous laser frequency tuning and cavity dither. Hence, the absorption line profile is more accurate, which is most suitable for low-pressure trace gas detection. This work has great potential for accurate selectivity and high sensitivity applications in human breath analysis and atmosphere sciences.

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Section: Methodsmentioning

confidence: 99%

Application of Near-Infrared Optical Feedback Cavity Enhanced Absorption Spectroscopy (OF-CEAS) to the Detection of Ammonia in Exhaled Human Breath

Luo

Tan

Long

2019

Sensors

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“…CEAS is essentially one of the direct absorption spectroscopy techniques and it takes advantage of a high-quality passive optical resonant cavity [17]. Since the laser satisfying the resonance condition can make multiple round trips in the passive cavity, the effective absorption path of the absorbing medium is enhanced exponentially over the limited optical path length [18]. Therefore, the measurement sensitivity of the CEAS technique is dramatically improved compared to the common direct absorption spectroscopy technique.…”

Section: Introductionmentioning

confidence: 99%

Study of a Mode Separation Due to Polarization Existing in a Cavity-Enhanced Absorption Spectroscopy

Guan

Chen

Cao

et al. 2021

Sensors

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A special phenomenon of resonance mode separation is observed during the study of a high sensitivity folded-cavity enhanced absorption spectroscopy for the measurement of trace gases. The phenomenon affects the measurement of gas absorption spectrum in the cavity. This resonant mode separation phenomenon of the resonant cavity is different from the resonant modes previously observed in linear-cavity enhanced absorption spectroscopy systems. To explore the mechanism of this phenomenon, a series of hypotheses are proposed. The most likely reason among these hypotheses is based on the different reflectance properties of the plane mirror at the fold of the cavity for S-polarized light and P-polarized light. Based on the matrix calculation method, the different reflectance and phase shift of the plane mirror for S-polarized light and P-polarized light are analyzed theoretically, and the results are in better agreement with the phenomena observed in the experiment. Finally, in order to eliminate the resonant mode separation phenomenon, line polarizers were added. By improving the system, the cavity enhanced absorption spectrum of residual water vapor in the cavity was successfully measured, and a minimum detectable absorption coefficient of αmin = 7.6 × 10−9 cm−1 can be obtained in a single laser scan of 10 s.

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“…EDFL is expensive and complex, and the resonant cavity of it is a linear cavity [37], [38]. In this kind of resonant cavity, the cavity mirror is in close contact with the end face of the optical fiber, and the cavity mirror is perpendicular to the axis of the optical fiber [39]. With this structure, the cavity mirror and the fiber end face are coupled with high precision to avoid loss due to beam divergence [40].…”

Section: Introductionmentioning

confidence: 99%

A Novel Erbium-Doped Fiber Laser Chaotic Circuit Based on Memristor and Its Circuit Implementation

Wang

et al. 2021

IEEE Access

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In this paper, a new chaotic system is proposed by adding a magnetron memristor to an erbium-doped fiber laser circuit, and its dynamical characteristics are analyzed. A special periodic coexistence attractor phenomenon was discovered during the analysis, which affects the dynamical characteristics of the system by changing the time parameters of the AC power supply and it is controllable. Finally, the chaotic system is implemented by constructing an equivalent analog circuit. Theoretical analysis and simulation results show that the new erbium-doped fiber laser chaotic system has good dynamical characteristics and it is easy to implement. Meanwhile, the rich dynamical characteristics of the system provide a basis for its application in image encryption and other fields.

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Optical-feedback cavity-enhanced absorption spectroscopy in a linear cavity: model and experiments

Cited by 24 publications

References 38 publications

Application of Near-Infrared Optical Feedback Cavity Enhanced Absorption Spectroscopy (OF-CEAS) to the Detection of Ammonia in Exhaled Human Breath

Application of Near-Infrared Optical Feedback Cavity Enhanced Absorption Spectroscopy (OF-CEAS) to the Detection of Ammonia in Exhaled Human Breath

Study of a Mode Separation Due to Polarization Existing in a Cavity-Enhanced Absorption Spectroscopy

A Novel Erbium-Doped Fiber Laser Chaotic Circuit Based on Memristor and Its Circuit Implementation

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