Objective-free optical-resolution photoacoustic microscopy

Kim, Chulhong; Park, Sungjo; Kim, Jongki; Lee, Sungrae; Lee, Chang-Ho; Jeon, Mansik; Kim, Jeehyun; Oh, Kyunghwan

doi:10.1117/1.jbo.18.1.010501

Cited by 28 publications

(16 citation statements)

References 12 publications

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“…[6][7][8] However, Bessel beams have many strong side lobes, which generate ghost signals, limiting their application in optical imaging. Similarly, in photoacoustic (PA) imaging, ultrasound transducers usually have large focal diameters (tens to hundreds of microns), and thus they receive most of the ghost signals from the side lobes of the Bessel beam, 9 which inhibits the direct application of Bessel beams in PA imaging.…”

Section: Introductionmentioning

confidence: 99%

Bessel-beam Grueneisen relaxation photoacoustic microscopy with extended depth of field

et al. 2015

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The short focal depth of a Gaussian beam limits the volumetric imaging speed of optical resolution photoacoustic microscopy (OR-PAM). A Bessel beam, which is diffraction free, provides a long focal depth, but its side lobes deteriorate image quality when the Bessel beam is directly employed to excite photoacoustic (PA) signals in OR-PAM. We present a nonlinear approach based on the Grueneisen relaxation effect to suppress the side-lobe artifacts in PA imaging. This method extends the focal depth of OR-PAM and speeds up volumetric imaging. We experimentally demonstrated a 1-mm focal depth with a 7-μm lateral resolution and volumetrically imaged a carbon fiber and red blood cell samples.

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Section: Introductionmentioning

confidence: 99%

Bessel-beam Grueneisen relaxation photoacoustic microscopy with extended depth of field

et al. 2015

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“…When compared with AR-PAM, OR-PAM has tighter optical focusing than acoustic focusing; thus, it has a better lateral resolution because it is easier to tightly focus the optical beam than the acoustic beam 6 . In contrast, the lateral resolution of AR-PAM is poorer than that of OR-PAM, but it can achieve an imaging depth beyond the optical diffusion limit 7 .…”

Section: Introductionmentioning

confidence: 99%

In vivo switchable optical- and acoustic-resolution photoacoustic microscopy

Jeon

Kim

2016

SPIE Proceedings

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Photoacoustic microscopy (PAM) provides high resolution and large penetration depth by utilizing the high optical sensitivity and low scattering of ultrasound. Hybrid PAM systems can be classified into two categories: opticalresolution photoacoustic microscopy (OR-PAM) and acoustic-resolution photoacoustic microscopy (AR-PAM). OR-PAM provides a very high lateral resolution with a strong optical focus, but the penetration depth is limited to one optical transport mean free path. AR-PAM provides a relatively greater penetration depth using diffused light in biological tissues. The resolution of AR-PAM is determined by its ultrasonic parameters. In this study, we performed an in vivo testing of a switchable OR-/AR-PAM system. In this system, two modes can be switched by changing its collimator lens and optical fiber. The lateral resolution of OR-PAM was measured using a resolution test target, and the full width at half maximum (FWHM) of the edge spread function was 2.5 µm. To calculate the lateral resolution of AR-PAM, a 6-µm-diameter carbon fiber was used, and the FWHM of the line spread function was 80.2 µm. We successfully demonstrated the multiscale imaging capability of the switchable OR-/AR-PAM system by visualizing microvascular networks in mouse ears, brain, legs, skin, and eyes.

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“…Unlike the disadvantages of Gaussian‐beam PAM (GB‐PAM) system due to diffraction, the BB is diffraction‐free due to their inherent properties, which enables it to extend the focal depth without compromising the focal spot size. The BB, however, generates undesired signals due to the presence of side lobes, which eventually appear as artifacts in optical imaging . Recently, a PAM system has been developed using a nonlinear Grueneisen relaxation (GR) effect that effectively suppresses the side lobes of the BB.…”

Section: Introductionmentioning

confidence: 99%

Reflection‐mode switchable subwavelength Bessel‐beam and Gaussian‐beam photoacoustic microscopy in vivo

Park

Lee

Jeon

et al. 2018

Journal of Biophotonics

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We have developed a reflection-mode switchable subwavelength Bessel-beam (BB) and Gaussian-beam (GB) photoacoustic microscopy (PAM) system. To achieve both reflection-mode and high resolution, we tightly attached a very small ultrasound transducer to an optical objective lens with numerical aperture of 1.0 and working distance of 2.5 mm. We used axicon and an achromatic doublet in our system to obtain the extended depth of field (DOF) of the BB. To compare the DOF performance achieved with our BB-PAM system against GB-PAM system, we designed our system so that the GB can be easily generated by simply removing the lenses. Using a 532 nm pulse laser, we achieved the lateral resolutions of 300 and 270 nm for BB-PAM and GB-PAM, respectively. The measured DOF of BB-PAM was approximately 229 μm, which was about 7× better than that of GB-PAM. We imaged the vasculature of a mouse ear using BB-PAM and GB-PAM and confirmed that the DOF of BB-PAM is much better than the DOF of GB-PAM. Thus, we believe that the high resolution achieved at the extended DOF by our system is very practical for wide range of biomedical research including red blood cell (RBC) migration in blood vessels at various depths and observation of cell migration or cell culture.

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Objective-free optical-resolution photoacoustic microscopy

Cited by 28 publications

References 12 publications

Bessel-beam Grueneisen relaxation photoacoustic microscopy with extended depth of field

Bessel-beam Grueneisen relaxation photoacoustic microscopy with extended depth of field

In vivo switchable optical- and acoustic-resolution photoacoustic microscopy

Reflection‐mode switchable subwavelength Bessel‐beam and Gaussian‐beam photoacoustic microscopy in vivo

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