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Volume 31, Issue 10
Displaying 1-8 of 8 articles from this issue
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Topical Papers on Optical Coherence Tomography
Topical Papers
Laser Review
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Kaoru MINOSHIMA2003 Volume 31 Issue 10 Pages 634
Published: 2003
Released on J-STAGE: February 03, 2006
JOURNAL FREE ACCESSDownload PDF (103K) -
J.G. Fujimoto2003 Volume 31 Issue 10 Pages 635-642
Published: 2003
Released on J-STAGE: February 03, 2006
JOURNAL FREE ACCESSOptical coherence tomography (OCT) is an emerging technology for performing high-resolution cross-sectional imaging. OCT is analogous to ultrasound, except that it uses light instead of sound to generate images of tissue with micron-scale resolution. OCT can be used as a type of “optical biopsy, ” because it provides images of tissue pathology in situ and in real time, without the need to excise and process specimens, as it is done in conventional excisional biopsy and histopathology. OCT promises applications in a wide range of clinical situations: to image tissue where standard excisional biopsy is hazardous or impossible, to guide surgical procedures, and to reduce sampling errors associated with excisional biopsy. This article reviews the principles and applications of OCT.View full abstractDownload PDF (2270K) -
Emmanuel ABRAHAM, Gedas JONUSAUSKAS, Jean OBERLÉ2003 Volume 31 Issue 10 Pages 643-646
Published: 2003
Released on J-STAGE: February 03, 2006
JOURNAL FREE ACCESSRecent developments of high speed imaging of biological tissues using optical radiation is reviewed in this paper. Especially, coherence optical gating (optical coherence tomography) and temporal optical gating (using femtosecond laser source) are able to provide video rate imaging of thick highly scattering biological samples with a micrometer transversal and depth resolution.View full abstractDownload PDF (1074K) -
Takeshi YASUI, Kaoru MINOSHIMA2003 Volume 31 Issue 10 Pages 647-653
Published: 2003
Released on J-STAGE: February 03, 2006
JOURNAL FREE ACCESSUltrafast time-resolved imaging gate provides interesting tools for observation of ultrafast phenomena, three-dimensional shape measurements, and biomedical imaging. In this paper, various time-resolved gating techniques based on electronic methods, coherence of light, or optical nonlinear effects are reviewed with regard to potential of time-resolved imaging. As a highly functional time-resolved imaging gate with femtosecond gating time and light amplification, we present here a femtosecond amplifying optical Kerr gate, which is realized by the optical Kerr effect in an excited state with light amplification and two perpendicularly polarized pump pulses with time delay. Furthermore, to evaluate its potential of practical application, we demonstrate three-dimensional shape measurements of a colored transparent object and a diffusing object with use of the femtosecond amplifying optical Kerr gate.View full abstractDownload PDF (1494K) -
Masamitsu HARUNA, Masato OHMI2003 Volume 31 Issue 10 Pages 654-662
Published: 2003
Released on J-STAGE: February 03, 2006
JOURNAL FREE ACCESSA practical OCT imaging system for ophthalmology became commercially available only five years after the first demonstration of OCT. OCT is thus an epoch-making technique in optics. In such development of the practical OCT system, however, Japanese researchers have been played second fiddle to the research groups in United States, although both basic concept and patent for OCT were proposed for the first time by Japanese researchers. Very recently, the domestic research activities for OCT increased remarkably, because it is necessary to develop many key technologies before OCT is widely applied for clinical diagnoses in the near future. At the present stage, OCT has several shortcomings and technical problems to be solved before its wide application for clinical diagnoses. In this paper, the description is focused on the present status of OCT in Japan as well as development of key technologies for the future OCT.View full abstractDownload PDF (2470K)
Laser Original
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Manabu SATO, Ichiro WAKAKI, Keiichi URUSHIYAMA, Yuuki WATANABE, Naohir ...2003 Volume 31 Issue 10 Pages 663-667
Published: 2003
Released on J-STAGE: February 03, 2006
JOURNAL FREE ACCESSWe have studied on the light intensity ratio of synthesized light source (SLS) for the improvement of spatial resolution of optical coherence tomography (OCT). SLS consists of two LEDs with wavelength 691 nm, spectral width 99 nm and 882 nm, 76 nm. The small imaging interferometer also consists of plan-convex lens of focal length 6 mm and diameter 6 mm, beam splitter and reference mirror with PZT. The axial resolution was measured at 1.2 μm with the side lobe intensity 42 % on the condition of intensity ratio of 1:0.5. The irradiated power was 18 μW. This axial resolution was 57 % compared to the axial resolution using a single LED. The image of test pattern was measured using the phase shift method and two lines with the interval of 9.8 μm were clearly measured. The lateral resolution was calculated at 1.1 μm from wavelength and numerical aperture.View full abstractDownload PDF (925K)
Regular Papers
Laser Original
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Ryouta FUJIOKA, Masaya FUJITA, Masayuki SUEKUNI, Fumihiko KANNARI2003 Volume 31 Issue 10 Pages 668-673
Published: 2003
Released on J-STAGE: February 03, 2006
JOURNAL FREE ACCESSOptical coherence tomography (OCT) working in the Fourier frequency domain, rather than in the time domain, can provide a coherence function of light scattered from a bulk sample at one exposure without any mechanical scanning. In this study, frequency-domain OCT is implemented as a single-mode fiber interferometry technique and its performance is quantitatively studied. From complex coherence functions obtained by spectral interferometry, we obtained tomographic images for absorption and dispersion spectra as well as a conventional optical coherence tomography image. As a principle of short-time Fourier transform, the spatial resolution of a spectrogram is lower than the coherence length of a light source. Therefore, the interpretation of spectrograms is not always straightforward.View full abstractDownload PDF (1313K) -
(Production and Performance Measurement of a 40 inch screen)Hyun Ho SONG, Yoshiharu MOMONOI, Taketo SHIBUYA, Toshio HONDA2003 Volume 31 Issue 10 Pages 674-678
Published: 2003
Released on J-STAGE: February 03, 2006
JOURNAL FREE ACCESSThe hybrid hologram screen, or HHS for short, is a system that enables the display of auto-stereoscopic images. Two of its main advantages are that the size of the view zone can be controlled, and that chromatic dispersion and chromatic aberration can be reduced by a small reference angle of the laser light when the hologram is recorded. We calculated the theoretical size of the view zone in which color images can be observed in the case of the 40 inch HHS. After actually building one, we measured the size of the view zone as it appears in practice.View full abstractDownload PDF (1842K)
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