Synergetic Resonance Matching of a Microphone and a Photoacoustic Cell

Sim, Joo Yong; Ahn, Chang–Geun; Huh, Chul; Chung, Kwang Hyo; Jeong, Eun-Ju; Kim, Bong Kyu

doi:10.3390/s17040804

Cited by 16 publications

(12 citation statements)

References 32 publications

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“…To obtain the spatial information of skin, we have developed a position scanning photoacoustic spectroscopy system. The setup for the mid infrared excitation of human skin in vivo and photoacoustic detection has been previously described 29 , 30 and the modified version for the scanning photoacoustic spectroscopy is shown in Fig. 1 .…”

Section: Resultsmentioning

confidence: 99%

“…In order to overcome these challenges, researchers reported on an optical-acoustic beam combiner or photoacoustic cavity to guide the ultrasound to the acoustic detector 22 , 49 , 50 . We chose the latter case, as reported previously 21 , 29 , 30 , 32 .…”

Section: Methodsmentioning

confidence: 99%

“…The microscopic images were taken in parallel at the same location where the photoacoustic images were acquired using a stereo microscope (SZ61TR, Olympus Inc. Tokyo, Japan) with an interchangeable-lens camera (A6000, Sony). The diameter of the main cavity of the photoacoustic cell was set to 8.25 mm which resulted in the largest signal to noise ratio when its resonant peak matched the resonance of the ultrasound transducer (SPM0404, Knowles Inc.) 29 .…”

Section: Methodsmentioning

confidence: 99%

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In vivo Microscopic Photoacoustic Spectroscopy for Non-Invasive Glucose Monitoring Invulnerable to Skin Secretion Products

Sim

Ahn

Jeong

et al. 2018

Sci Rep

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116

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Photoacoustic spectroscopy has been shown to be a promising tool for non-invasive blood glucose monitoring. However, the repeatability of such a method is susceptible to changes in skin condition, which is dependent on hand washing and drying due to the high absorption of infrared excitation light to the skin secretion products or water. In this paper, we present a method to meet the challenges of mid-infrared photoacoustic spectroscopy for non-invasive glucose monitoring. By obtaining the microscopic spatial information of skin during the spectroscopy measurement, the skin region where the infrared spectra is insensitive to skin condition can be locally selected, which enables reliable prediction of the blood glucose level from the photoacoustic spectroscopy signals. Our raster-scan imaging showed that the skin condition for in vivo spectroscopic glucose monitoring had significant inhomogeneities and large variability in the probing area where the signal was acquired. However, the selective localization of the probing led to a reduction in the effects of variability due to the skin secretion product. Looking forward, this technology has broader applications not only in continuous glucose monitoring for diabetic patient care, but in forensic science, the diagnosis of malfunctioning sweat pores, and the discrimination of tumors extracted via biopsy.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

In vivo Microscopic Photoacoustic Spectroscopy for Non-Invasive Glucose Monitoring Invulnerable to Skin Secretion Products

Sim

Ahn

Jeong

et al. 2018

Sci Rep

Self Cite

116

View full text Add to dashboard Cite

show abstract

“…Based on the photoacoustic effect, photoacoustic spectroscopy technology aims to form a heat source to inspire the sound source of the perturbed gas through the absorption of a certain power P 0 of light. The absorption coefficient α abs of a specific gas can be obtained through the detection of the sound source [24], [25]. If the photoacoustic signal S PA is detected by microphone (sensitivity S m ).…”

Section: Principle Of Coupled Spectroscopy Measurementmentioning

confidence: 99%

Study on the Photoacoustic Technology to Simultaneous In-Situ Detection of the Cavity Ring-Down Spectrum for Multi-Optical Parameters

Jin

Xie

et al. 2020

IEEE Photonics J.

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A simultaneous in-situ detection technique to obtain multi-optical parameters was proposed. The same 403.56 nm, low power, blue diode laser was used to conduct the cavity ring-down spectroscopy and photoacoustic spectroscopy, which were coupled. Four photoacoustic spectra were applied to the simultaneous in-situ detection of the cavity ring-down spectrum, which were systematically compared and analyzed for the first time. And the main performance of the systems varied with the arrangement of the photoacoustic pool. The results reveal that the photoacoustic response was optimized by the high reflectivity mirror with the pool constant of 1450.64 (Pα•cm)/W and the signal sensitivity of 0.2562 μv/ppb. The intensity value of the photoacoustic pool inside the cavity ring down was superimposed to 48.45% of the initial intensity. The corresponding experimental results were consistent with the theoretical analysis and shown the coupled cavity could suitable for simultaneous in-situ measurement of high concentration. The coupled two detection techniques detected different optical parameters and thus provided a new method for the simultaneous in-situ detection of the multi-optical parameters of specific atmospheric components.

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“…It can be used for ultra-sensitive calibration-free trace-gas detection and fast spectral scan applications [13]. Sim et al proposed an approach to match the resonant characteristics of a photoacoustic cell with that of a microphone in order to enhance the SNR in the photoacoustic sensor [14]. Using this approach, the signal-to-noise ratio is increased 3.5-fold from the optimized to non-optimized cell in the photoacoustic spectroscopy system.…”

Section: Introductionmentioning

confidence: 99%

Gas Absorption Center-Based Wavelength Calibration Technique in QEPAS System for SNR Improvement

et al. 2018

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A simple and effective wavelength calibration scheme is proposed in a quartz enhanced photoacoustic spectroscopy (QEPAS) system for trace gas detection. A reference gas cell is connected an InGaAs photodetector for detecting the absorption intensity peak caused by the gas to calibrate the gas absorption center using distributed feedback laser diode (DFB-LD) with sawtooth wave driver current. The gas absorption wavelength calibration and gas sensing operations are conducted at a special internal to eliminate the wavelength shift of DFB-LD caused by the ambient fluctuations. Compared with the conventional wavelength modulation spectroscopy (WMS), this method uses a lower lock-in amplifier bandwidth and averaging algorithm to improve signal noise ratio (SNR). Water vapor is chosen as a sample gas to evaluate its performance. In the experiments, the impact of sawtooth wave frequency and lock-in amplifier bandwidth on the harmonic signal is analyzed, and the wavelength-calibration technique-based system achieves a minimum detection limit (MDL) of 790 ppbv and SNR with 13.4 improvement factor compared with the conventional WMS system.

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Synergetic Resonance Matching of a Microphone and a Photoacoustic Cell

Cited by 16 publications

References 32 publications

In vivo Microscopic Photoacoustic Spectroscopy for Non-Invasive Glucose Monitoring Invulnerable to Skin Secretion Products

In vivo Microscopic Photoacoustic Spectroscopy for Non-Invasive Glucose Monitoring Invulnerable to Skin Secretion Products

Study on the Photoacoustic Technology to Simultaneous In-Situ Detection of the Cavity Ring-Down Spectrum for Multi-Optical Parameters

Gas Absorption Center-Based Wavelength Calibration Technique in QEPAS System for SNR Improvement

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