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Volume 29, Issue 11
Displaying 1-13 of 13 articles from this issue
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Kenichi UEDA2001 Volume 29 Issue 11 Pages 703
Published: November 15, 2001
Released on J-STAGE: March 17, 2010
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Hiroshi FUKUMURA2001 Volume 29 Issue 11 Pages 704
Published: November 15, 2001
Released on J-STAGE: March 17, 2010
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Steffen BAUDACH, Jörg KRÜGER, Wolfgang KAUTEK2001 Volume 29 Issue 11 Pages 705-709
Published: November 15, 2001
Released on J-STAGE: March 17, 2010
JOURNAL FREE ACCESSAblation of polymer films such as polyimide, polycarbonate, polyethylenterephthalate, polytetrafluoroethylene and polymethylmethacrylate were investigated with a Ti: sapphire laser system (150 fs, 800 nm). The single pulse threshold increased from 1.0 Jcm-2 of polyimide to 2.6 Jcm-2 of polymethylmethacrylate. This correlates with the increase of the optical band gap suggesting a multi-photon absorption mechanism. All polymers show incubation effects. A stronger incubation could be found for polycarbonate, polyethylenterephthalate, and polymethylmethacrylate in contrast to the “inert” polymers polyimide and polytetrafluoroethylene due to irreversible chemical alterations. All polymers except polyimide exhibited melting and the generation of vapour yielding swelling. Polyimide only sublimates and/or degrades. Ripples parallel to the electric field vector were generated with linear polarization of repeated laser pulses whereas circular polarization resulted in nanostructure arrays of the order of -100 nm.View full abstractDownload PDF (1786K) -
Yoichiroh HOSOKAWA, Tsuyoshi ASAHI, Hiroshi MASUHARA2001 Volume 29 Issue 11 Pages 710-716
Published: November 15, 2001
Released on J-STAGE: March 17, 2010
JOURNAL FREE ACCESSA novel femtosecond laser etching and its mechanism of Cu-phthalocyanine solid were investigated by using fs (170 fs) and ns (100 ns) pulses of a 780 nm Ti: Sapphire laser. Above ablation thresholds, the depth etched by fs laser excitation becomes constant and is almost independent of laser fluence, while the depth etched by ns laser excitation increases gradually. We name the unique fs ablation phenomenon “discrete etching”. In order to reveal the evolutions from fs laser excitation to the nm etching, we measured directly excitation energy relaxation and surface morphology change with fs transient absorption spectroscopy and fs surface light scattering imaging, respectively. On the basis of the results, we propose a fs laser ablation model that ultrafast stress increase brings about mechanical disruption leading to the discrete etching behavior.View full abstractDownload PDF (1417K) -
2001 Volume 29 Issue 11 Pages 716-716,729
Published: November 15, 2001
Released on J-STAGE: March 17, 2010
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Hiroyuki AOKI, Shinzaburo ITO2001 Volume 29 Issue 11 Pages 717-721
Published: November 15, 2001
Released on J-STAGE: March 17, 2010
JOURNAL FREE ACCESSScanning near-field optical microscopy (SNOM) is an emerging scanning probe microscopic technique that enables one to carry out spectroscopic and time-resolved measurements with a sub-wavelength spatial resolution. We applied SNOM to investigate nanometric structures of polymer systems: 1) the phase separation structures of polymer blend monolayers, and 2) the structural inhomogeneity of polymer gels. The fluorescence imaging and time-resolved measurement of the energy transfer process in a local area revealed the assembly structures of polymer chains. In the two-dimensionally phase-separated polymer blend system, the phase interface was in the order of 100 nm, which was much larger than that for the three-dimensional system. The polymer gel has a hierarchic structure consisting of domains on scales of lOnm and 1μm. These findings showed that SNOM is a versatile technique to obtain molecular information on a mesoscopic/nanometric scale.View full abstractDownload PDF (1248K) -
Yoshimasa KAWATA2001 Volume 29 Issue 11 Pages 722-725
Published: November 15, 2001
Released on J-STAGE: March 17, 2010
JOURNAL FREE ACCESSWe present the application of organic films as the detection system of near-optical microscopy. The optical field distribution is recorded as the topography of a photosensitive film, and the topographical distribution is detected with an atomic force microscope. This technique presents the possibility of a new type of near-field microscope without use of probe tips for illumination or detection of light. The observation result of a biological specimen is also presented.View full abstractDownload PDF (1056K) -
Masahiro GOTO, Maki KISHIMOTO, Hiroshi FUKUMURA2001 Volume 29 Issue 11 Pages 726-729
Published: November 15, 2001
Released on J-STAGE: March 17, 2010
JOURNAL FREE ACCESSFunctional organic molecules can be space-selectively implanted into polymer films by pulsed laser irradiation. This method has been developed for fabricating nano- and micro-scale fluorescent patterns on polymer surfaces. Two approaches employing scanning probe microscopy and conventional optical microscopy have been demonstrated. The former used a glass pipette having aperture of 100 nm, doped with fluorescent organic molecules at the tip. The distance between the tip and a polymer surface was controlled by a piezo driver to within a few tens of nanometer. Then nanosecond pulsed laser light was guided into the pipette with a glass fiber producing a nano-jet of organic molecules that is ejected towards the polymer surface, resulting in disklike implantation with a diameter of a few hundred nanometers. It was also demonstrated that a conventional microscope is useful to manufacture micro-scale patterns with functional organic molecules. This mechanism of the microscopic implantation is discussed based on experimental parameters affecting implantation size.View full abstractDownload PDF (874K) -
Osamu NAKAMURA, Tomoyuki KANEKO2001 Volume 29 Issue 11 Pages 730-733
Published: November 15, 2001
Released on J-STAGE: March 17, 2010
JOURNAL FREE ACCESSDestructive effect induced by focused ultra-short pulsed laser has been used to perform micro-scale processing of metal or glass materials. Since the destructive effect is based on a multiphoton process and can be localized in the focusing area, the micro-processing can be performed with high three-dimensional resolution. We developed a laser processing system for laser surgery inside of living cells with the high spatial resolution, and monitored the response of the cells during laser surgery. In the experiment, we discovered that laser irradiation can induce physiological activities of cells. Focused laser light from a mode-locked Ti: Sapphire laser (780 nm, 80 fs, 82 MHz) irradiated HeLa cells loaded with fluorescence calcium indicator (fluo-4/AM). Soon after the irradiation, increase of the calcium concentration was seen around the focusing spot, then propagating to the entire cell. This result indicates that the increase of the calcium concentration was induced due to nonlinear optical process such as multiphoton absorption.View full abstractDownload PDF (1040K) -
Thomas LIPPERT, Christian DAVID, Marc HAUER, Claude PHIPPS, Alexander ...2001 Volume 29 Issue 11 Pages 734-738
Published: November 15, 2001
Released on J-STAGE: March 17, 2010
JOURNAL FREE ACCESSPhotopolymers based on triazene-groups were designed for UV laser ablation. The tested triazene-polymer reveals a low threshold fluence and unusually high ablation rates at low and high fluences. The polymer decomposes into gaseous products, resulting in clean ablation structures without surface contaminations. The triazene-polymer was also tested for two different applications at two different irradiation wavelengths, i.e. in the UV (308 nm) and in the near-IR (935 nm). Diffractive gray tone phase masks optimized for laser ablation were applied to fabricate microoptical elements. The triazene-polymereveals also superior properties for applications in the near-IR. Near-IR irradiation is used to create a plasma which could be used as thruster for microsatellites. The carbon-doped triazene-polymer shows higher values of the momentum coupling coefficient and specific impulse than a commercial polymer. The well-defined threshold for the maximum momentum coupling coefficient was only observed for the designed polymer.View full abstractDownload PDF (1486K) -
Akito ISHIDA2001 Volume 29 Issue 11 Pages 739-743
Published: November 15, 2001
Released on J-STAGE: March 17, 2010
JOURNAL FREE ACCESSLocalised surface plasmon field around nanowells on gold film has been applied to enhance the fluorescence of BODIPY-dyes and Eu (TTF) 3 towards ultra-high throughput fluorescence analysis using nanowells integrated on a microtip. A 100 nm gold film with nanowells have been prepared on a 0.17 mm glass cover-slip by projection method using 500 nm or 1μm polystyrene spheres, and then fluorescence-stained with BODIPY-dyes or Eu (TTF) 3. The gold films have been excited by grazing illumination or by ATR using a 404 nm semiconductor laser. Both excitation methods gave remarkably enhanced fluorescence at the nanowells. The fluorescence image by ATR demonstrates that the surface plasmon field is strongly localised and scattered at the nanoholes giving comet-like spots.View full abstractDownload PDF (1448K) -
Hiroaki MINAMIDE, Kodo KAWASE, Kazuhiro IMAI, Atsushi SATO, Hiromasa I ...2001 Volume 29 Issue 11 Pages 744-748
Published: November 15, 2001
Released on J-STAGE: March 17, 2010
JOURNAL FREE ACCESSWe demonstrate a widely tunable terahertz (THz) -wave parametric oscillator (TPO) in a ring cavity configuration using a novel frequency-tuning method involving rotating a single mirror forming the cavity. The TPO consisted of a nonlinear optical MgO: LiNbO3 crystal in a three-mirror ring cavity. We obtained continuous tuning of THz-wave in the 0.93 to 2.7 THz range by adjusting the mirror. The maximum THz-wave output of 69.6 pJ/pulse at 1.3 THz was coupled out from a single Si prism coupler. The absorption of HCl gas was measured in order to check the tuning controllability. The high performance of the TPO was confirmed from the transmission dip of the measured spectrum in agreement with the known center absorption lines.View full abstractDownload PDF (820K) -
Ryosuke KODAMA2001 Volume 29 Issue 11 Pages 749
Published: November 15, 2001
Released on J-STAGE: March 17, 2010
JOURNAL FREE ACCESSDownload PDF (166K)
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