title: Optical parametrically gated microscopy in scattering media.
abstract: High-resolution imaging in turbid media has been limited by the intrinsic compromise between the gating efficiency (removal of multiply-scattered 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 general-purpose optical amplifier applicable to a wide range of optical imaging techniques.
authors.forename: Youbo
authors.initials: Y
authors.lastname: Zhao
authors.forename: Steven G
authors.initials: SG
authors.lastname: Adie
authors.forename: Haohua
authors.initials: H
authors.lastname: Tu
authors.forename: Yuan
authors.initials: Y
authors.lastname: Liu
authors.forename: Benedikt W
authors.initials: BW
authors.lastname: Graf
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Chaney
authors.forename: Marina
authors.initials: M
authors.lastname: Marjanovic
authors.forename: Stephen A
authors.initials: SA
authors.lastname: Boppart
mesh_terms: D003952:Diagnostic Imaging / Q000295:instrumentation*; D006801:Humans; D008027:Light; D008853:Microscopy / Q000295:instrumentation*; D009391:Nephelometry and Turbidimetry / Q000295:instrumentation*; D055095:Optics and Photonics; D012542:Scattering, Radiation; D041623:Tomography, Optical Coherence / Q000295:instrumentation*