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Volume 34, Issue 7
Displaying 1-10 of 10 articles from this issue
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Masamitsu HARUNA2006 Volume 34 Issue 7 Pages 468-469
Published: July 15, 2006
Released on J-STAGE: March 26, 2014
JOURNAL FREE ACCESSDownload PDF (292K) -
Masato OHMI, Masamitsu HARUNA2006 Volume 34 Issue 7 Pages 470-475
Published: July 15, 2006
Released on J-STAGE: March 26, 2014
JOURNAL FREE ACCESSOptical coherence tomography (OCT) is very promising for high-resolution cross-sectional imaging under-neath the surface of biological tissue. The axial resolution of OCT is determined by the coherence length of the light source used in a low coherence interferometer. In this paper, we review imaging characteristics of high-resolution OCT using broadband light sources as well as the coherence length. In the wavelength region of 0.8μm, a femtosecond laser and the thermal light source provides us the coherence length of a few micron or less using the bulk-optic interferometer. In the wavelength region of 1.3μm/1.5μm, a broadband fiber ASE and a supercontinuum light are useful for the high-resolution OCT under the condition where the wavelengthindependent fiber directional coupler is used.View full abstractDownload PDF (4408K) -
Masahide ITOH, Yoshiaki YASUNO, Toyohiko YATAGAI2006 Volume 34 Issue 7 Pages 476-482
Published: July 15, 2006
Released on J-STAGE: March 26, 2014
JOURNAL FREE ACCESSOptical coherence tomography (OCT) has been started from the applications of ophthalmology. Spectral domain OCT (SD-OCT) is proposed as an alternative to the time domain OCT (TD-OCT). SD-OCT based on spectral interference does not require mechanical scanning, and is able to get phase information without any additional signal processing. Using phase information as a contrast engine of OCT, we can also develop a polarization sensitive SD-OCT (PS-SD-OCT) and Doppler OCT. The application of SD-OCT including swept source OCT (SS-OCT) is introduced. Two dimensional and three dimensional in vivo human retinal images are shown.View full abstractDownload PDF (13009K) -
Kohji OHBAYASHI2006 Volume 34 Issue 7 Pages 483-487
Published: July 15, 2006
Released on J-STAGE: March 26, 2014
JOURNAL FREE ACCESSRecent developments of optical frequency domain imaging (OFDI) are reviewed. Two methods of OFDI using different types of frequency swept sources are compared.View full abstractDownload PDF (1006K) -
Manabu SATO, Yuuki WATANABE2006 Volume 34 Issue 7 Pages 488-493
Published: July 15, 2006
Released on J-STAGE: March 26, 2014
JOURNAL FREE ACCESSRecently, progress has been made in developing full-field optical coherence tomography (FF OCT) with the advantage of acquiring an en-face sectional image. Based on the Linnik interferometer, the FF OCT achieves an acquisition speed of 250 frames/s using a cw Xenon lamp and CMOS camera to measure OCT images of rat eye in vivo. We have been studying quadrature-fringes full-field OCT (QF FF OCT) to measure the 3D images and to sense the activity of rat cortex. QF FF OCT enables acquiring the en face sectional image with only two exposures. The principle of QF FF OCT and the 3D OCT images (4mm×4mm×2.9mm depth) of in situ rat cortex are introduced.View full abstractDownload PDF (7906K) -
Masahiro AKIBA, Kin Pui CHAN2006 Volume 34 Issue 7 Pages 494-498
Published: July 15, 2006
Released on J-STAGE: March 26, 2014
JOURNAL FREE ACCESSFull-field optical coherence tomography (FF-OCT) is a newly developed technique capable of acquiring a horizontal cross-sectional (en-face) image without lateral scanning. In this paper two configurations of FFOCT system are described. The first one employs a frequency-synchronous detection method that operates a pair of CCD cameras as the heterodyne detector arrays. A series of en-face images are thus acquired at the camera frame rate in a single longitudinal scan, making the fast acquisition of three-dimensional information possible. The second system is based on a Linnik microscope for optical coherence microcopy. Using a tungsten halogen lamp as the low-cost ultra-broadband source, sub-cellular imaging is demonstrated in biological objects.View full abstractDownload PDF (9838K) -
OCT-OphthalmoscopeTokio UENO2006 Volume 34 Issue 7 Pages 499-504
Published: July 15, 2006
Released on J-STAGE: March 26, 2014
JOURNAL FREE ACCESSOCT-Ophthalmoscope scans the human retina in 2 dimensions by a galvo-scanner at high speed and constructs 2 dimensional OCT images (C-Scan images) by detecting the interference signal produced by the measuring light and the reference light. Furthermore, by moving the reference mirror along the optical axis, this system can construct 3 dimensional OCT images. The resolution of the system is 9 microns in the longitudinal direction and 18 microns in the transversal direction.
It enables us by its unique C-Scan OCT images to observe retinal images not only in a one-dimensional intersection but also in the area or the volume and to diagnose or evaluate retinal disease objectively and numerically.View full abstractDownload PDF (9012K) -
Mitsuru SUGO, Yasuo SHIBATA, Ryoko YOSHIMURA2006 Volume 34 Issue 7 Pages 505-508
Published: July 15, 2006
Released on J-STAGE: March 26, 2014
JOURNAL FREE ACCESSIn this paper, we describe high-power (> 50 mW), wideband (> 50 nm) 1.3 pm super luminescent diodes (SLDs). This dispels our preconception that an SLD cannot emit high-power light like an LD. The SLDs have a tilted stripe and both facets have a window structure and antireflection coating. This design reduces the spectrum ripple (< 0.4 dB). An SLD module exhibited a high coupling efficiency of over 70 % and a high power of more than 30 mW in a single-mode fiber. These SLDs are suitable for use in optical coherence tomography (OCT).View full abstractDownload PDF (3583K) -
Mitsuhiro HIGASHIHATA, Hisashi TAKEMOTO, Tatsuo OKADA2006 Volume 34 Issue 7 Pages 509-513
Published: July 15, 2006
Released on J-STAGE: March 26, 2014
JOURNAL FREE ACCESSThe operational characteristics of an ultra-broadband light source using the stimulated Raman scattering in a single-mode optical fiber for the application to optical coherence tomography is described. The ultra-broadband output light covering from 770 nm to 1650 nm was obtained using a 500-m-long single-mode phosphorus-doped Si02 optical fiber pumped by a self Q-switched Ti: sapphire laser with a spectral width of 13 nm. When a white-light Michelson interferometer was constructed using the fiber Raman laser as a light source, a longitudinal spatial resolution of 1.7 μm was achieved.View full abstractDownload PDF (776K) -
Shinji NISHIKAWA, Haruyasu ITOH, Takanori AZUMA, Shin-ichiro AOSHIMA, ...2006 Volume 34 Issue 7 Pages 514-518
Published: July 15, 2006
Released on J-STAGE: March 26, 2014
JOURNAL FREE ACCESSWe processed metal and resin using intense femtosecond laser pulses transmitted through a hollow fiber. The laser pulses used in the experiment were generated by a regenerative amplifier and had a wavelength of 800 nm, a pulse duration of 50 fs, a pulse energy of 0.63 mJ (i. e., a peak power of 12.6 GW), and a repetition rate of 1 kHz. The hollow fiber was 1 m long, and its inner surface, coated with silver, was 0.7 mm in diameter. To avoid nonlinear modulation due to air breakdown, we evacuated the fiber's core. From by measuring the transmission characteristics of the fiber, we confirmed that optical pulses of 3.56 GW peak power (160 fs duration and 0.57 mJ energy) were obtained as fiber outputs when the fiber was straight. By scanning the output end of the fiber, we suitably processed a carbon tool steel and poly-ethylene terephthalate resin using fiber delivered femtosecond pulses.View full abstractDownload PDF (6357K)
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