Image formation in turbid media under a microscope

Gan, Xiaosong; Schilders, S. P.; Gu, Miṅ

doi:10.1364/josaa.15.002052

Cited by 30 publications

(26 citation statements)

References 19 publications

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“…It is expected that this decreased pinhole size contributes to the efficient removal of the multiply-scattered light background, as shown by the experimental results presented later. Although the smaller pinhole may give more attenuation of the ballistic signal [7][8][9], this is compensated by the high optical gain of the OPA process. As shown by Fig.…”

Section: Principlementioning

confidence: 99%

“…These diffusing photons lose most of the information about their initial propagating direction (wave vector), which if not effectively rejected, can greatly degrade the imaging resolution. Therefore, the attainable imaging depth and resolution in scattering media rely heavily on the effectiveness of the imaging techniques for the detection of the ballistic photon signal against the multiplyscattering background [7][8][9].…”

Section: Introductionmentioning

confidence: 99%

“…Currently, for 3-D optical imaging in scattering media, the detection of ballistic photons is achieved by using high-sensitivity photo-detectors along with a variety of optical gating methods, such as time gating [5,10,11], confocal gating [7,9,12], polarization gating [13,14], and coherence (effectively time) gating [15,16], which help to reject the multiplyscattered light background (in addition to the optical sectioning functions of these techniques). In these gating approaches, there exists an intrinsic limitation, i.e., the compromise between signal strength and background removal [7][8][9].…”

Section: Introductionmentioning

confidence: 99%

“…In these gating approaches, there exists an intrinsic limitation, i.e., the compromise between signal strength and background removal [7][8][9]. For instance, in confocal microscopy, a smaller pinhole rejects more multiply-scattered background light but at the expense of signal loss, whereas a larger pinhole (weaker gate) collect more ballistic photon signals, but these are compromised by a stronger multiply-scattered light background.…”

Section: Introductionmentioning

confidence: 99%

“…This inevitably leads to a limited imaging depth due to weak signal, as well as a possible limited resolution due to the strong background. The resultant well-known trade-off between resolution and imaging depth affects nearly all of the current ballistic photon imaging techniques, including confocal microscopy, optical coherence tomography (OCT), and timegated imaging in scattering media [7][8][9].…”

Section: Introductionmentioning

confidence: 99%

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Optical parametrically gated microscopy in scattering media

Zhao¹,

Adie²,

Tu³

et al. 2014

Opt. Express

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High-resolution imaging in turbid media has been limited by the intrinsic compromise between the gating efficiency (removal of multiplyscattered light background) and signal strength in the existing optical gating techniques. This leads to shallow depths due to the weak ballistic signal, and/or degraded resolution due to the strong multiply-scattering background -the well-known trade-off between resolution and imaging depth in scattering samples. In this work, we employ a nonlinear optics based optical parametric amplifier (OPA) to address this challenge. We demonstrate that both the imaging depth and the spatial resolution in turbid media can be enhanced simultaneously by the OPA, which provides a high level of signal gain as well as an inherent nonlinear optical gate. This technology shifts the nonlinear interaction to an optical crystal placed in the detection arm (image plane), rather than in the sample, which can be used to exploit the benefits given by the high-order parametric process and the use of an intense laser field. The coherent process makes the OPA potentially useful as a generalpurpose optical amplifier applicable to a wide range of optical imaging techniques. References and links 1. J. A. Fujimoto and D. Farkas, Biomedical Optical Imaging, (Oxford University Press, 2009 R207-R227 (2003). 6. V. Ntziachristos, "Going deeper than microscopy: the optical imaging frontier in biology," Nat. Methods 7(8), 603-614 (2010). 7. X. S. Gan, S. P. Schilders, and M. Gu, "Image formation in turbid media under a microscope," J. Opt. Soc. Am.A 15(8), 2052-2058 (1998). 8. M. Kempe, A. Z. Genack, W. Rudolph, and P. Dorn, "Ballistic and diffuse light detection in confocal and heterodyne imaging systems," J. Opt. Soc. Am. A 14(1), 216-223 (1997). 9. J. M. Schmitt, A. Knüttel, and M. Yadlowsky, "Confocal microscopy in turbid media," J. Opt. Soc. Am. A 11(8), 2226-2235 (1994). 10. L. Wang, P. P. Ho, C. Liu, G. Zhang, and R. R. Alfano, "Ballistic 2-d imaging through scattering walls using an ultrafast optical kerr gate," Science 253(5021), 769-771 (1991). 11. J. G. Fujimoto, S. De Silvestri, E. P. Ippen, C. A. Puliafito, R. Margolis, and A. Oseroff, "Femtosecond optical ranging in biological systems," Opt. Lett. 11(3), 150-152 (1986

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Section: Principlementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Optical parametrically gated microscopy in scattering media

Zhao¹,

Adie²,

Tu³

et al. 2014

Opt. Express

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Enhancement of optical coherence microscopy in turbid media by an optical parametric amplifier

Zhao

Liu

et al. 2014

J. Biophoton

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We report the enhancement in imaging performance of a spectral-domain optical coherence microscope (OCM) in turbid media by incorporating an optical parametric amplifier (OPA). The OPA provides a high level of optical gain to the sample arm, thereby improving the signal-to-noise ratio of the OCM by a factor of up to 15 dB. A unique nonlinear confocal gate is automatically formed in the OPA, which enables selective amplification of singly scattered (ballistic) photons against the multiply-scattered light background. Simultaneous enhancement in both imaging depth and spatial resolution in imaging microstructures in highly light-scattering media are demonstrated with the combined OPA-OCM setup. Typical OCM inteferograms (left) and images (right) without and with OPA.

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