1
|
Cho SW, Phan TTV, Nguyen VT, Park SM, Lee H, Oh J, Kim CS. Efficient label-free in vivo photoacoustic imaging of melanoma cells using a condensed NIR-I spectral window. PHOTOACOUSTICS 2023; 29:100456. [PMID: 36785577 PMCID: PMC9918423 DOI: 10.1016/j.pacs.2023.100456] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 01/25/2023] [Accepted: 01/25/2023] [Indexed: 06/18/2023]
Abstract
In this paper, we propose an efficient label-free in vivo photoacoustic (PA) imaging of melanoma using a condensed near infrared-I (NIR-I) supercontinuum light source. Although NIR-II spectral window is advantageous such as longer penetration depth compared to the NIR-I region, supercontinuum light sources emitting both NIR-I and NIR-II region could lower the efficiency to target melanoma because of low optical power density in the melanoma's absorption spectra. To exploit efficient in vivo PA imaging of melanoma, we demonstrated the light source emitting from visible (532-600 nm) to NIR-I (600-1000 nm) by optimizing stimulated Raman scattering induced supercontinuum generation. The melanoma's structure is successfully differentiated from blood vessels at a high pulse energy of 2.5 µJ and a flexible pulse repetition rate (PRR) of 5-50 kHz. The proposed light source with the microjoules energies and tens of kHz of PRR can potentially accelerate clinical trials such as early diagnosis of melanoma.
Collapse
Affiliation(s)
- Soon-Woo Cho
- Engineering Research Center for Color-modulated Extra-sensory Perception Technology, Pusan National University, Busan 46241, the Republic of Korea
| | - Thi Tuong Vy Phan
- Center for Advanced Chemistry, Institute of Research and Development, Duy Tan University, Danang 550000, Viet Nam
- Department of Environmental and Chemical Engineering, Duy Tan University, Danang 550000, Viet Nam
| | - Van Tu Nguyen
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
| | - Sang Min Park
- Department of Cogno-Mechatronics Engineering, Pusan National University, Busan 46241, the Republic of Korea
| | - Hwidon Lee
- Harvard Medical School, Boston, Massachusetts MA 02115, USA
- Wellman Center for Photomedicine, Harvard Medical School and Massachusetts General Hospital, 40 Blossom Street, Boston, MA 02114, USA
| | - Junghwan Oh
- Department of Biomedical Engineering, Pukyong National University, Busan 48513, the Republic of Korea
- Ohlabs Corporation, Busan 48513, the Republic of Korea
| | - Chang-Seok Kim
- Engineering Research Center for Color-modulated Extra-sensory Perception Technology, Pusan National University, Busan 46241, the Republic of Korea
- Department of Cogno-Mechatronics Engineering, Pusan National University, Busan 46241, the Republic of Korea
| |
Collapse
|
2
|
Muller JW, Arabul MÜ, Schwab HM, Rutten MCM, van Sambeek MRHM, Wu M, Lopata RGP. Modeling toolchain for realistic simulation of photoacoustic data acquisition. JOURNAL OF BIOMEDICAL OPTICS 2022; 27:096005. [PMID: 36104838 PMCID: PMC9470848 DOI: 10.1117/1.jbo.27.9.096005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 08/31/2022] [Indexed: 06/15/2023]
Abstract
SIGNIFICANCE Physics-based simulations of photoacoustic (PA) signals are used to validate new methods, to characterize PA setups and to generate training datasets for machine learning. However, a thoroughly validated PA simulation toolchain that can simulate realistic images is still lacking. AIM A quantitative toolchain was developed to model PA image acquisition in complex tissues, by simulating both the optical fluence and the acoustic wave propagation. APPROACH Sampling techniques were developed to decrease artifacts in acoustic simulations. The performance of the simulations was analyzed by measuring the point spread function (PSF) and using a rotatable three-channel phantom, filled with cholesterol, a human carotid plaque sample, and porcine blood. Ex vivo human plaque samples were simulated to validate the methods in more complex tissues. RESULTS The sampling techniques could enhance the quality of the simulated PA images effectively. The resolution and intensity of the PSF in the turbid medium matched the experimental data well. Overall, the appearance, signal-to-noise ratio and speckle of the images could be simulated accurately. CONCLUSIONS A PA toolchain was developed and validated, and the results indicate a great potential of PA simulations in more complex and heterogeneous media.
Collapse
Affiliation(s)
- Jan-Willem Muller
- Eindhoven University of Technology, Photoacoustics and Ultrasound Laboratory Eindhoven, Department of Biomedical Engineering, Eindhoven, The Netherlands
- Catharina Hospital, Department of Vascular Surgery, Eindhoven, The Netherlands
| | - Mustafa Ü. Arabul
- Eindhoven University of Technology, Photoacoustics and Ultrasound Laboratory Eindhoven, Department of Biomedical Engineering, Eindhoven, The Netherlands
| | - Hans-Martin Schwab
- Eindhoven University of Technology, Photoacoustics and Ultrasound Laboratory Eindhoven, Department of Biomedical Engineering, Eindhoven, The Netherlands
| | - Marcel C. M. Rutten
- Cardiovascular Biomechanics Group, Department of Biomedical Engineering, Eindhoven, The Netherlands
| | - Marc R. H. M. van Sambeek
- Eindhoven University of Technology, Photoacoustics and Ultrasound Laboratory Eindhoven, Department of Biomedical Engineering, Eindhoven, The Netherlands
- Catharina Hospital, Department of Vascular Surgery, Eindhoven, The Netherlands
| | - Min Wu
- Eindhoven University of Technology, Photoacoustics and Ultrasound Laboratory Eindhoven, Department of Biomedical Engineering, Eindhoven, The Netherlands
| | - Richard G. P. Lopata
- Eindhoven University of Technology, Photoacoustics and Ultrasound Laboratory Eindhoven, Department of Biomedical Engineering, Eindhoven, The Netherlands
| |
Collapse
|
3
|
Recent Technical Progression in Photoacoustic Imaging—Towards Using Contrast Agents and Multimodal Techniques. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11219804] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
For combining optical and ultrasonic imaging methodologies, photoacoustic imaging (PAI) is the most important and successful hybrid technique, which has greatly contributed to biomedical research and applications. Its theoretical background is based on the photoacoustic effect, whereby a modulated or pulsed light is emitted into tissue, which selectively absorbs the optical energy of the light at optical wavelengths. This energy produces a fast thermal expansion in the illuminated tissue, generating pressure waves (or photoacoustic waves) that can be detected by ultrasonic transducers. Research has shown that optical absorption spectroscopy offers high optical sensitivity and contrast for ingredient determination, for example, while ultrasound has demonstrated good spatial resolution in biomedical imaging. Photoacoustic imaging combines these advantages, i.e., high contrast through optical absorption and high spatial resolution due to the low scattering of ultrasound in tissue. In this review, we focus on advances made in PAI in the last five years and present categories and key devices used in PAI techniques. In particular, we highlight the continuously increasing imaging depth achieved by PAI, particularly when using exogenous reagents. Finally, we discuss the potential of combining PAI with other imaging techniques.
Collapse
|
4
|
Park SM, Kim DY, Cho SW, Kim BM, Lee TG, Kim CS, Lee SW. Quickly Alternating Green and Red Laser Source for Real-time Multispectral Photoacoustic Microscopy. PHOTOACOUSTICS 2020; 20:100204. [PMID: 33014706 PMCID: PMC7522855 DOI: 10.1016/j.pacs.2020.100204] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 08/25/2020] [Accepted: 08/26/2020] [Indexed: 05/06/2023]
Abstract
Multispectral photoacoustic microscopy uses a wavelength-dependent absorption difference as a contrast mechanism to image the target molecule. In this paper, we present a novel multispectral pulsed fiber laser source, which selectively alternates the excitation wavelengths between green and red colors based on the stimulated Raman scattering (SRS) effect for imaging. This laser has a high pulse repetition rate (PRR) of 300 kHz and high pulse energy of more than 200 nJ meeting the real-time requirements of optical-resolution photoacoustic microscopy imaging. By switching the polarization state of the pump light and optical paths of the pump light, the operating wavelengths of the light source can be selectively alternated at the same fast PRR for any two SRS peak wavelengths between 545 and 655 nm. At 545 nm excitation wavelength, molecular photoacoustic signals from both blood vessels and gold nanorods were obtained simultaneously. However, at 655 nm, the photoacoustic signals of gold nanorods were dominant because the absorption of light by the blood vessels decreased drastically in the spectral region over 600 nm. Thus the multispectral photoacoustic system designed using the novel laser source implemented here could simultaneously monitor the time-dependent fast movement of two molecules independently, having different wavelength-dependent absorption properties at a high repetition rate of 0.49 frames per second (fps).
Collapse
Affiliation(s)
- Sang Min Park
- Department of Cogno-Mechatronics Engineering, Pusan National University, Busan 46241, Republic of Korea
| | - Do Yeon Kim
- Safety Measurement Institute, Korea Research Institute of Standards and Science, Daejeon 34113, Republic of Korea
- Department of Bio-Convergence Engineering, Korea University, Seoul 02841, Republic of Korea
| | - Soon-Woo Cho
- Department of Cogno-Mechatronics Engineering, Pusan National University, Busan 46241, Republic of Korea
| | - Beop-Min Kim
- Department of Bio-Convergence Engineering, Korea University, Seoul 02841, Republic of Korea
- Department of Biomedical Engineering, Korea University, Seoul 02841, Republic of Korea
| | - Tae Geol Lee
- Safety Measurement Institute, Korea Research Institute of Standards and Science, Daejeon 34113, Republic of Korea
| | - Chang-Seok Kim
- Department of Cogno-Mechatronics Engineering, Pusan National University, Busan 46241, Republic of Korea
- Corresponding author at: Department of Cogno-Mechatronics Engineering, Busan National University, 46241, Republic of Korea
| | - Sang-Won Lee
- Safety Measurement Institute, Korea Research Institute of Standards and Science, Daejeon 34113, Republic of Korea
- Department of Medical Physics, University of Science and Technology, Daejeon 34113, Republic of Korea
- Corresponding authors.
| |
Collapse
|
5
|
Dasa MK, Nteroli G, Bowen P, Messa G, Feng Y, Petersen CR, Koutsikou S, Bondu M, Moselund PM, Podoleanu A, Bradu A, Markos C, Bang O. All-fibre supercontinuum laser for in vivo multispectral photoacoustic microscopy of lipids in the extended near-infrared region. PHOTOACOUSTICS 2020; 18:100163. [PMID: 32042589 PMCID: PMC6997905 DOI: 10.1016/j.pacs.2020.100163] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 01/15/2020] [Accepted: 01/22/2020] [Indexed: 05/06/2023]
Abstract
Among the numerous endogenous biological molecules, information on lipids is highly coveted for understanding both aspects of developmental biology and research in fatal chronic diseases. Due to the pronounced absorption features of lipids in the extended near-infrared region (1650-1850 nm), visualisation and identification of lipids become possible using multi-spectral photoacoustic (optoacoustic) microscopy. However, the spectroscopic studies in this spectral region require lasers that can produce high pulse energies over a broad spectral bandwidth to efficiently excite strong photoacoustic signals. The most well-known laser sources capable of satisfying the multi-spectral photoacoustic microscopy requirements (tunability and pulse energy) are tunable nanosecond optical parametric oscillators. However, these lasers have an inherently large footprint, thus preventing their use in compact microscopy systems. Besides, they exhibit low-repetition rates. Here, we demonstrate a compact all-fibre, high pulse energy supercontinuum laser that covers a spectral range from 1440 to 1870 nm with a 7 ns pulse duration and total energy of 18.3 μJ at a repetition rate of 100 kHz. Using the developed high-pulse energy source, we perform multi-spectral photoacoustic microscopy imaging of lipids, both ex vivo on adipose tissue and in vivo to study the development of Xenopus laevis tadpoles, using six different excitation bands over the first overtone transition of C-H vibration bonds (1650-1850 nm).
Collapse
Affiliation(s)
- Manoj K. Dasa
- DTU Fotonik, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Gianni Nteroli
- Applied Optics Group, University of Kent, Canterbury, UK
| | - Patrick Bowen
- NKT Photonics A/S, Blokken 84, 3460 Birkerød, Denmark
| | - Giulia Messa
- Medway School of Pharmacy, University of Kent, Chatham, UK
| | - Yuyang Feng
- COPAC A/S, Diplomvej 381, 2800 Kongens Lyngby, Denmark
| | - Christian R. Petersen
- DTU Fotonik, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
- NORBLIS IVS, Virumgade 35D, 2830 Virum, Denmark
| | | | - Magalie Bondu
- NKT Photonics A/S, Blokken 84, 3460 Birkerød, Denmark
| | | | | | - Adrian Bradu
- Applied Optics Group, University of Kent, Canterbury, UK
| | - Christos Markos
- DTU Fotonik, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
- NORBLIS IVS, Virumgade 35D, 2830 Virum, Denmark
| | - Ole Bang
- DTU Fotonik, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
- NORBLIS IVS, Virumgade 35D, 2830 Virum, Denmark
- NKT Photonics A/S, Blokken 84, 3460 Birkerød, Denmark
| |
Collapse
|
6
|
Guney G, Uluc N, Demirkiran A, Aytac-Kipergil E, Unlu MB, Birgul O. Comparison of noise reduction methods in photoacoustic microscopy. Comput Biol Med 2019; 109:333-341. [PMID: 31129310 DOI: 10.1016/j.compbiomed.2019.04.035] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2019] [Revised: 04/27/2019] [Accepted: 04/27/2019] [Indexed: 01/12/2023]
Abstract
Photoacoustic microscopy (PAM) is classified as a hybrid imaging technique based on the photoacoustic effect and has been frequently studied in recent years. Photoacoustic (PA) signals are inherently recorded in a noisy environment and are also exposed to noise by system components. Therefore, it is essential to reduce the noise in PA signals to reconstruct images with less error. In this study, an image reconstruction algorithm for PAM system was implemented and different filtering approaches for denoising were compared. Studies were carried out in three steps: simulation, experimental phantom and blood cell studies. FIR low-pass and band-pass filters and Discrete Wavelet Transform (DWT) based filters (mother wavelets: "bior3.5″, "bior3.7″, "sym7″) with four different thresholding techniques were examined. For the evaluation purposes, Root Mean Square Error (RMSE), Signal to Noise Ratio (SNR) and Contrast to Noise Ratio (CNR) metrics were calculated. In the simulation studies, the most effective methods were obtained as: sym7/heursure/hard thresh. combination (low and medium level noise) and bior3.7/sqtwolog/soft thresh. combination (high-level noise). In experimental phantom studies, noise was classified into five levels. Different filtering approaches perform better depending on the SNR of PA images. For the blood cell study, based on the standard deviation in the background, sym7/sqtwolog/soft thresh. combination provided the best improvement and this result supported the experimental phantom results.
Collapse
Affiliation(s)
- Gokhan Guney
- Department of Biomedical Engineering, Ankara University, 06830, Ankara, Turkey.
| | - Nasire Uluc
- Department of Physics, Bogazici University, 34342, Istanbul, Turkey
| | - Aytac Demirkiran
- Department of Physics, Bogazici University, 34342, Istanbul, Turkey
| | | | | | - Ozlem Birgul
- Department of Biomedical Engineering, Ankara University, 06830, Ankara, Turkey
| |
Collapse
|
7
|
Uluc N, Unlu MB, Gulsen G, Erkol H. Extended photoacoustic transport model for characterization of red blood cell morphology in microchannel flow. BIOMEDICAL OPTICS EXPRESS 2018; 9:2785-2809. [PMID: 30258691 PMCID: PMC6154189 DOI: 10.1364/boe.9.002785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 03/21/2018] [Accepted: 04/11/2018] [Indexed: 06/08/2023]
Abstract
The dynamic response behavior of red blood cells holds the key to understanding red blood cell related diseases. In this regard, an understanding of the physiological functions of erythrocytes is significant before focusing on red blood cell aggregation in the microcirculatory system. In this work, we present a theoretical model for a photoacoustic signal that occurs when deformed red blood cells pass through a microfluidic channel. Using a Green's function approach, the photoacoustic pressure wave is obtained analytically by solving a combined Navier-Stokes and photoacoustic equation system. The photoacoustic wave expression includes determinant parameters for the cell deformability such as plasma viscosity, density, and red blood cell aggregation, as well as involving laser parameters such as beamwidth, pulse duration, and repetition rate. The effects of aggregation on blood rheology are also investigated. The results presented by this study show good agreements with the experimental ones in the literature. The comprehensive analytical solution of the extended photoacoustic transport model including a modified Morse type potential function sheds light on the dynamics of aggregate formation and demonstrates that the profile of a photoacoustic pressure wave has the potential for detecting and characterizing red blood cell aggregation.
Collapse
Affiliation(s)
- Nasire Uluc
- Department of Physics, Bogazici University, 34342 Bebek, Istanbul,
Turkey
| | - Mehmet Burcin Unlu
- Department of Physics, Bogazici University, 34342 Bebek, Istanbul,
Turkey
- Global Station for Quantum Medical Science and Engineering, Global Institution for Collaborative Research and Education (GI-CoRE), Hokkaido University, Sapporo 060-8648,
Japan
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA,
USA
| | - Gultekin Gulsen
- Department of Radiological Sciences, University of California, Irvine, CA,
USA
| | - Hakan Erkol
- Department of Physics, Bogazici University, 34342 Bebek, Istanbul,
Turkey
| |
Collapse
|
8
|
Dasa MK, Markos C, Maria M, Petersen CR, Moselund PM, Bang O. High-pulse energy supercontinuum laser for high-resolution spectroscopic photoacoustic imaging of lipids in the 1650-1850 nm region. BIOMEDICAL OPTICS EXPRESS 2018; 9:1762-1770. [PMID: 29675317 PMCID: PMC5905921 DOI: 10.1364/boe.9.001762] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Revised: 03/09/2018] [Accepted: 03/13/2018] [Indexed: 05/22/2023]
Abstract
We propose a cost-effective high-pulse energy supercontinuum (SC) source based on a telecom range diode laser-based amplifier and a few meters of standard single-mode optical fiber, with a pulse energy density as high as ~25 nJ/nm in the 1650-1850 nm regime (factor >3 times higher than any SC source ever used in this wavelength range). We demonstrate how such an SC source combined with a tunable filter allows high-resolution spectroscopic photoacoustic imaging and the spectroscopy of lipids in the first overtone transition band of C-H bonds (1650-1850 nm). We show the successful discrimination of two different lipids (cholesterol and lipid in adipose tissue) and the photoacoustic cross-sectional scan of lipid-rich adipose tissue at three different locations. The proposed high-pulse energy SC laser paves a new direction towards compact, broadband and cost-effective source for spectroscopic photoacoustic imaging.
Collapse
Affiliation(s)
- Manoj Kumar Dasa
- Department of Photonics Engineering, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Christos Markos
- Department of Photonics Engineering, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Michael Maria
- Department of Photonics Engineering, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Christian R. Petersen
- Department of Photonics Engineering, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | | | - Ole Bang
- Department of Photonics Engineering, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
- NKT Photonics A/S, Blokken 84, Birkerød 3460, Denmark
| |
Collapse
|
9
|
Label-free photoacoustic microscopy for in-vivo tendon imaging using a fiber-based pulse laser. Sci Rep 2018; 8:4805. [PMID: 29556037 PMCID: PMC5859263 DOI: 10.1038/s41598-018-23113-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 03/06/2018] [Indexed: 02/07/2023] Open
Abstract
Tendons are tough, flexible, and ubiquitous tissues that connect muscle to bone. Tendon injuries are a common musculoskeletal injury, which affect 7% of all patients and are involved in up to 50% of sports-related injuries in the United States. Various imaging modalities are used to evaluate tendons, and both magnetic resonance imaging and sonography are used clinically to evaluate tendons with non-invasive and non-ionizing radiation. However, these modalities cannot provide 3-dimensional (3D) structural images and are limited by angle dependency. In addition, anisotropy is an artifact that is unique to the musculoskeletal system. Thus, great care should be taken during tendon imaging. The present study evaluated a functional photoacoustic microscopy system for in-vivo tendon imaging without labeling. Tendons have a higher density of type 1 collagen in a cross-linked triple-helical formation (65–80% dry-weight collagen and 1–2% elastin in a proteoglycan-water matrix) than other tissues, which provides clear endogenous absorption contrast in the near-infrared spectrum. Therefore, photoacoustic imaging with a high sensitivity to absorption contrast is a powerful tool for label-free imaging of tendons. A pulsed near-infrared fiber-based laser with a centered wavelength of 780 nm was used for the imaging, and this system successfully provided a 3D image of mouse tendons with a wide field of view (5 × 5 mm2).
Collapse
|
10
|
Bondu M, Marques M, Moselund P, Lall G, Bradu A, Podoleanu A. Multispectral photoacoustic microscopy and optical coherence tomography using a single supercontinuum source. PHOTOACOUSTICS 2018; 9:21-30. [PMID: 29707477 PMCID: PMC5914199 DOI: 10.1016/j.pacs.2017.11.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 10/13/2017] [Accepted: 11/20/2017] [Indexed: 05/07/2023]
Abstract
We report on the use of a single supercontinuum (SC) source for multimodal imaging. The 2-octave bandwidth (475-2300 nm) makes the SC source suitable for optical coherence tomography (OCT) as well as for multispectral photoacoustic microscopy (MPAM). The IR band centered at 1310 nm is chosen for OCT to penetrate deeper into tissue with 8 mW average power on the sample. The 500-840 nm band is used for MPAM. The source has the ability to select the central wavelength as well as the spectral bandwidth. An energy of more than 35 nJ within a less than 50 nm bandwidth is achieved on the sample for wavelengths longer than 500 nm. In the present paper, we demonstrate the capabilities of such a multimodality imaging instrument based on a single optical source. In vitro mouse ear B-scan images are presented.
Collapse
Affiliation(s)
- M. Bondu
- University of Kent, Applied Optics Group, School of Physical Sciences, Ingram building, Canterbury CT2 7NH, United Kingdom
- NKT Photonics A/S, Blokken 84, Birkeroed 3460, Denmark
- Corresponding author.
| | - M.J. Marques
- University of Kent, Applied Optics Group, School of Physical Sciences, Ingram building, Canterbury CT2 7NH, United Kingdom
| | - P.M. Moselund
- NKT Photonics A/S, Blokken 84, Birkeroed 3460, Denmark
| | - G. Lall
- Medway School of Pharmacy, University of Kent, Chatham ME4 4TB, United Kingdom
| | - A. Bradu
- University of Kent, Applied Optics Group, School of Physical Sciences, Ingram building, Canterbury CT2 7NH, United Kingdom
| | - A. Podoleanu
- University of Kent, Applied Optics Group, School of Physical Sciences, Ingram building, Canterbury CT2 7NH, United Kingdom
| |
Collapse
|
11
|
Demirkiran A, Karakuzu A, Erkol H, Torun H, Unlu MB. Analysis of microcantilevers excited by pulsed-laser-induced photoacoustic waves. OPTICS EXPRESS 2018; 26:4906-4919. [PMID: 29475334 DOI: 10.1364/oe.26.004906] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Accepted: 01/04/2018] [Indexed: 06/08/2023]
Abstract
This study presents a simulation-based analysis on the excitation of microcantilever in air using pulsed-laser-induced photoacoustic waves. A model was designed and coded to investigate the effects of consecutive photoacoustic waves, arising from a spherical light absorber illuminated by short laser pulses. The consecutiveness of the waves were adjusted with respect to the pulse repetition frequency of the laser to examine their cumulative effects on the oscillation of microcantilever. Using this approach, oscillation characteristics of two rectangular cantilevers with different resonant frequencies (16.9 kHz and 505.7 kHz) were investigated in the presence of the random oscillations. The results show that the effective responses of the microcantilevers to the consecutive photoacoustic waves provide steady-state oscillations, when the pulse repetition frequency matches to the fundamental resonant frequency or its lower harmonics. Another major finding is that being driven by the same photoacoustic pressure value, the high frequency cantilever tend to oscillate at higher amplitudes. Some of the issues emerging from these findings may find application area in atomic force microscopy actuation and photoacoustic signal detection.
Collapse
|
12
|
Zhang Q, Chang J, Wang Q, Wang Z, Wang F, Qin Z. Acousto-Optic Q-Switched Fiber Laser-Based Intra-Cavity Photoacoustic Spectroscopy for Trace Gas Detection. SENSORS 2017; 18:s18010042. [PMID: 29295599 PMCID: PMC5795532 DOI: 10.3390/s18010042] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 12/17/2017] [Accepted: 12/19/2017] [Indexed: 02/05/2023]
Abstract
We proposed a new method for gas detection in photoacoustic spectroscopy based on acousto-optic Q-switched fiber laser by merging a transmission PAS cell (resonant frequency f0 = 5.3 kHz) inside the fiber laser cavity. The Q-switching was achieved by an acousto-optic modulator, achieving a peak pulse power of ~679 mW in the case of the acousto-optic modulation signal with an optimized duty ratio of 10%. We used a custom-made fiber Bragg grating with a central wavelength of 1530.37 nm (the absorption peak of C2H2) to select the laser wavelength. The system achieved a linear response (R2 = 0.9941) in a concentration range from 400 to 7000 ppmv, and the minimum detection limit compared to that of a conventional intensity modulation system was enhanced by 94.2 times.
Collapse
Affiliation(s)
- Qinduan Zhang
- School of Information Science and Engineering and Shandong Provincial Key Laboratory of Laser Technology and Application, Shandong University, Jinan 250100, China.
| | - Jun Chang
- School of Information Science and Engineering and Shandong Provincial Key Laboratory of Laser Technology and Application, Shandong University, Jinan 250100, China.
| | - Qiang Wang
- Department of Mechanical and Automation Engineering, The Chinese University of Hong Kong, New Territories, Hong Kong, China.
| | - Zongliang Wang
- School of Physics Science and Information Technology and Shandong Key Laboratory of Optical Communication Science and Technology, Liaocheng University, Liaocheng 252059, China.
| | - Fupeng Wang
- School of Information Science and Engineering and Shandong Provincial Key Laboratory of Laser Technology and Application, Shandong University, Jinan 250100, China.
| | - Zengguang Qin
- School of Information Science and Engineering and Shandong Provincial Key Laboratory of Laser Technology and Application, Shandong University, Jinan 250100, China.
| |
Collapse
|