TY - GEN
T1 - Confocal microscopy without pinhole
AU - Barbastathis, George
AU - Balberg, Michal
AU - Brady, David J.
N1 - Funding Information: for recording the hologram was outside the trench. The image of the trench corresponds to the dark region in Figure 4 because the bottom of the trench is out-of-focus. Only five planes along y and one along z were sampled, in order to minimize inaccuracies due to the backlash of the translation stage and the decay of the hologram. A dense three-dimensional scan could have been obtained using a piezo-electric deflector and a fixed hologram. In conclusion, we have demonstrated confocal scanning microscopy using a volume hologram as a shift-variant element, matched to object depth. The dynamic range of volume holographic confocal imaging depends on the holographic diffraction efficiency (in our experiment it was « 10""*), and is material-limited. It is possible to achieve higher difrraction efficiency by using different materials, e.g. photopolymers of photorefractive polymers. These operate in the transmission geometry and are typically thin (< 1 mm); the depth resolution of a confocal microscope implemented that way would, therefore, be poorer than the 90° geometry. Future work involves the combination of the volume holographic confocal imaging principle with complex filtering in both the transmission and 90° geometries for super-resolution [3, 4, 6] and hyper-spectral imaging [6]. We are grateful to Chang Liu and Bo Kyoung Choi for fabricating the micromachined surface sample. This research was funded by the Air Force Office of Scientific Research. Funding Information: We axe grateful to Chang Liu and Bo Kyoung Choi for fabricating the micromachined surface sample. This research was funded by the Air Force Office of Scientific Research. Publisher Copyright: © 1999 OSA/OC 1999.
PY - 1999
Y1 - 1999
N2 - Confocal microscopes achieve depth resolution by use of a pinhole. On-axis, in-focus point-source objects are imaged exactly inside the pinhole, and give maximal intensity. Out-of-focus objects, even on-axis, produce extended (blurred) images, and are filtered out by the limited aperture of the pinhole. Theoretically, the depth resolution is optimal when an infinitessimally small pinhole is used [1]. However, such an ad hoc filter does not match perfectly the impulse response of any realistic optical system. In practice, the minimum pinhole size, and, hence, the depth resolution limit, are determined by light efficiency (i.e., the required dynamic range of the measurement) and the broadening of the focal spot by lens aberrations [2]. Using a complex filter, implemented as a thin diftactive element, instead of a pinhole infront of the detector, has been proposed as a means for achieving super-resolution [3, 4].
AB - Confocal microscopes achieve depth resolution by use of a pinhole. On-axis, in-focus point-source objects are imaged exactly inside the pinhole, and give maximal intensity. Out-of-focus objects, even on-axis, produce extended (blurred) images, and are filtered out by the limited aperture of the pinhole. Theoretically, the depth resolution is optimal when an infinitessimally small pinhole is used [1]. However, such an ad hoc filter does not match perfectly the impulse response of any realistic optical system. In practice, the minimum pinhole size, and, hence, the depth resolution limit, are determined by light efficiency (i.e., the required dynamic range of the measurement) and the broadening of the focal spot by lens aberrations [2]. Using a complex filter, implemented as a thin diftactive element, instead of a pinhole infront of the detector, has been proposed as a means for achieving super-resolution [3, 4].
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M3 - Conference contribution
T3 - Optics InfoBase Conference Papers
BT - Optics in Computing, OC 1999
PB - Optica Publishing Group (formerly OSA)
T2 - Optics in Computing, OC 1999
Y2 - 13 April 1999 through 13 April 1999
ER -