Open AccessModulated-alignment dual-axis (MAD) confocal microscopy for deep optical sectioning in tissues
Author(s) -
Steven Y. Leigh,
Ye Chen,
Jonathan Liu
Publication year - 2014
Publication title -
biomedical optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.362
H-Index - 86
ISSN - 2156-7085
DOI - 10.1364/boe.5.001709
Subject(s) - optical sectioning , confocal microscopy , optics , microscopy , light sheet fluorescence microscopy , confocal , optical coherence tomography , optical microscope , materials science , optical axis , endomicroscopy , scanning confocal electron microscopy , physics , scanning electron microscope , lens (geology)
A strategy is presented to enable optical-sectioning microscopy with improved contrast and imaging depth using low-power (0.5 - 1 mW) diode laser illumination. This technology combines the inherent strengths of focal-modulation microscopy and dual-axis confocal (DAC) microscopy for rejecting out-of-focus and multiply scattered background light in tissues. The DAC architecture is unique in that it utilizes an intersecting pair of illumination and collection beams to improve the spatial-filtering and optical-sectioning performance of confocal microscopy while focal modulation selectively 'labels' in-focus signals via amplitude modulation. Simulations indicate that modulating the spatial alignment of dual-axis beams at a frequency f generates signals from the focal volume of the microscope that are modulated at 2f with minimal modulation of background signals, thus providing nearly an order-of-magnitude improvement in optical-sectioning contrast compared to DAC microscopy alone. Experiments show that 2f lock-in detection enhances contrast and imaging depth within scattering phantoms and fresh tissues.