The Review of Laser Engineering
Online ISSN : 1349-6603
Print ISSN : 0387-0200
ISSN-L : 0387-0200
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Volume 25, Issue 12
Displaying 1-16 of 16 articles from this issue
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  • [title in Japanese]
    Masahiro NAKATSUKA
    1997 Volume 25 Issue 12 Pages 829-830
    Published: December 15, 1997
    Released on J-STAGE: February 26, 2010
    DOIhttps://doi.org/10.2184/lsj.25.829
    JOURNAL FREE ACCESS
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  • On the Topical Papers of Laser Plant Factory
    Masamoto TAKATSUJI
    1997 Volume 25 Issue 12 Pages 831
    Published: December 15, 1997
    Released on J-STAGE: February 26, 2010
    DOIhttps://doi.org/10.2184/lsj.25.831
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  • Proposal of a Laser Plant Factory
    Masamoto TAKATSUJI, Yasuhiro MORI
    1997 Volume 25 Issue 12 Pages 832-835
    Published: December 15, 1997
    Released on J-STAGE: February 26, 2010
    DOIhttps://doi.org/10.2184/lsj.25.832
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    Possibility of a completely-controlled plant factory using red laser diodes (LD) together with blue LD or light emitting diodes (LED) is discussed. It is shown that laser plant factory (LPF) may be materialized if the price of LD becomes several handreds yen per 1W of output power. Recent rapid progress and price reduction of LD for digital video disc (DVD) support the realization of LPF in near future.
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  • Light Emitting Diodes as the Irradiation Source for Plant Factories
    Hiroyuki WATANABE
    1997 Volume 25 Issue 12 Pages 836-840
    Published: December 15, 1997
    Released on J-STAGE: February 26, 2010
    DOIhttps://doi.org/10.2184/lsj.25.836
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    Light emitting diodes (LEDs) are a potential irradiation source for intensive plant culture systems like plant factories. LEDs have small size, low mass, a long functional life, and narrow spectral output. We have examined the growth profiles of leaf lettuce and other plant species grown under red light with supplemental blue and far-red light of LEDs compared with other artificial light. On the basis of our experimental data, the characteristics of LEDs as irradiation source for plants and the prospects for plant factory equipping LED lighting systems are overviewed in this paper.
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  • [title in Japanese]
    [in Japanese], [in Japanese], [in Japanese]
    1997 Volume 25 Issue 12 Pages 840-840,844
    Published: December 15, 1997
    Released on J-STAGE: February 26, 2010
    DOIhttps://doi.org/10.2184/lsj.25.840
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  • Application of Red Laser Diode as A Light Source of Plant Production
    Hiroshi TSUCHIYA, Aya YAMAZAKI, Hirofumi MIYAJIMA, Takayoshi HONMA, Hi ...
    1997 Volume 25 Issue 12 Pages 841-844
    Published: December 15, 1997
    Released on J-STAGE: February 26, 2010
    DOIhttps://doi.org/10.2184/lsj.25.841
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    We have developed high-power and high-efficiency AlGaInP laser diodes with the power of 250mW and 700mW for a plant production light source. Their wavelength is 680nm that is efficient for the photosynthesis. By planting a lettuce seedling under the laser diode irradiation (250mW), the possibility of growing plant under the laser was confirmed. However, the leaves of the lettuce grown under the red laser diode were long and thin, and also their weights were light compared to the lettuce grown under high-pressure sodium lamp or metal halide lamp. Similar tendency was found on the lettuce grown at a higher light power. By adding a blue light, for example a blue fluorescent light or a blue LED, the shape of the leaves was much improved.
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  • Application of a Red Laser Diode and Blue Light Emitting Diodes to Plant Growth Experiments
    Yoshio NISHIDA, Masanobu YAMANAKA
    1997 Volume 25 Issue 12 Pages 845-849
    Published: December 15, 1997
    Released on J-STAGE: February 26, 2010
    DOIhttps://doi.org/10.2184/lsj.25.845
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    Plant growth experiments by using visible semiconductor diodes, that is, light emitting diode (LED) and laser diode (LD) are reviewed. It is well known that the spectra needed for green plants growth are red and blue. The central wavelengths of emission spectrum of LED used are 660nm and 450nm. The oscillation wavelength of LD used is 670nm. We grew a plant (sprouting radish) for the first time by using a red LD and two blue LEDs as a light source for photosynthesis. In particular experimental methods and results under pulsed illuminations are described in detail.
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  • Present Status and Future of Blue LEDs and LDs
    Shuji NAKAMURA
    1997 Volume 25 Issue 12 Pages 850-854
    Published: December 15, 1997
    Released on J-STAGE: February 26, 2010
    DOIhttps://doi.org/10.2184/lsj.25.850
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    High-power InGaN single-quantum-well (SQW) structure blue/green light-emitting diodes (LEDs) with an output power of 3-5mW were fabricated. The continuous-wave operation of bluish-purple InGaN multi-quantum-well (MQW)-structure laser diodes (LDs) was achieved at room temperature with a lifetime of 35 hours. The threshold current and the voltage of the LD were 80mA and 5.5V, respectively. By changing the indium composition of the InGaN well layers of the InGaN MQW LDs, the emission wavelength of the LDs was varied between 390nm and 440nm which was suitable for the application of a laser plant factory. Photocurrent spectra of the InGaN SQW LEDs were measured at room temperature. The energy differences between the absorption and the emission energy of the blue/green InGaN SQW LEDs were 290 and 570meV. Both spontaneous and stimulated emission originated from these deep localized energy states.
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  • Table-Top Ultra-Short High-Intensity Pulse Lasers
    Shuji SAKABE
    1997 Volume 25 Issue 12 Pages 855-863
    Published: December 15, 1997
    Released on J-STAGE: February 26, 2010
    DOIhttps://doi.org/10.2184/lsj.25.855
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    The technical elements for table-top chirped-pulse amplification (CPA) lasers to generate ultrashort high-intensity pulse light, that is, mode-locked oscillators for femtosecond pulse generation, pulse stretcher and compressor for CPA, amplifiers to generate high energy, and compensation of spectra-narrowing and phase distorsion, are reviewed. Feasibility of table-top petawatt lasers is also briefly discussed.
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  • Carbon Isotope Separation by Infrared Multiple Photon Decomposition with a Free Electron Laser
    Shizuma KURIBAYASHI, Takio TOMIMASU, Syunichi KAWANISHI, Shigeyoshi AR ...
    1997 Volume 25 Issue 12 Pages 864-869
    Published: December 15, 1997
    Released on J-STAGE: February 26, 2010
    DOIhttps://doi.org/10.2184/lsj.25.864
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    To verify infrared multiple photon decomposition (IRMPD) by our free electron laser (FEL), 0.8 Ton of CF3I was irradiated with 9.5μm FEL pulses. The fluence of the macropulse used was estimated to be 8J/cm2 at the beam waist. About 3% of the CF3I sample was found to decompose without selectivity by irradiating it with 3. 6 × 104 macropulses. In order to examine decomposition yields and isotope selectivities, 5 Torr of CHBrF2 was irradiated at a fluence of 16J/cm2 with FEL pulses in the wavelength region from 9.3 to 9.7μm. The IRMPD of CHBrF2 was found to produce C2F4. The significant enrichment of 13C in the product was obtained with the irradiation at 9.7μm. The atomic fraction of 13C obtained was as high as 6%. The decomposition yield is related to the diffusion of reactant molecules in a vicinity of a small photolysis volume.
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  • Wide-View Collision Avoidance Sensor System with Variable Detected Area
    Jun YAMADA, Yuichiro MIZUNO, Norio TSUDA, Hideo FURUHASHI, Yoshiyuki U ...
    1997 Volume 25 Issue 12 Pages 870-874
    Published: December 15, 1997
    Released on J-STAGE: February 26, 2010
    DOIhttps://doi.org/10.2184/lsj.25.870
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    A new type of collision avoidance sensor system to detect an obstacle in a wide area for unmannded trucks has been developed. This sensor system is composed of a semiconductor laser and a CCD camera. The sensor can detect an obstacle in wide area, because a sheet-like laser-beam is used for illumination and a CCD camera is used as a two-dimentional area sensor. The signal from the CCD camera is processed by a simple analog circuit without a complex image processing. The detected area of the sensor system can be varied in any distance and any width by the gate pulse signal which is made from the syncronising signal in video signal. It is concluded that this simple device is possible to be used as a wide-view collision avoidance sensor system with a variable detected area.
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  • Development of a Bistatic Imaging Lidar Capable of Daytime and Nighttime Observations
    Kazuo MEKI, Hidetsugu MISHIMA, Takuya KAWAHARA, Yasunori SAITO, Akio N ...
    1997 Volume 25 Issue 12 Pages 875-879
    Published: December 15, 1997
    Released on J-STAGE: February 26, 2010
    DOIhttps://doi.org/10.2184/lsj.25.875
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    We describe a bistatic imaging lidar system based on a CCD camera, which is capable of daytime and nighttime observations. For reducing the daytime background, the gated image intensifier (I.I.) was used as a high speed shutter synchronized with each laser pulse. Background signals decreased to 1/5000 with a gatetime of 20μs without reducing scattered laser signals. Therefore, our system was able to detect scattered laser signals with SNR of 13.3-15.7 even at daytime. The performance of the lidar system was confirmed by continuous observation through 24 hours.
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  • Temporal Waveform Control of Laser, Pulse by Frequency Chirping
    Yoshinori KATO, Hidetsugu YOSHIDA, Hisanori FUJITA, Sadao NAKAI
    1997 Volume 25 Issue 12 Pages 880-884
    Published: December 15, 1997
    Released on J-STAGE: February 26, 2010
    DOIhttps://doi.org/10.2184/lsj.25.880
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    Arbitrary temporal waveform control can be achieved by means of amplifier gain control with chirped laser pulse. We designed and manufactured a high-speed and high-voltage frequency modulator to get large chirping with flexibility. This modulator produced chirping of 76.5GHz within 0.7ns for 0.532μm laser. We have performed basic experiments and developed a simulation model for temporal waveform control of laser pulse using frequency chirping of 42GHz. Experimental results were compared with simulation results based on the Frantz-Nodvik theory. Experimental results showed good agreement with simulation results. It is indicated that desired temporal waveform can be shaped by frequency chirping.
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  • Properties of the Single Mode Operation of the LD Pumped Tm:YAG Laser
    Fumio MATSUZAKA, Hiroshi HARA
    1997 Volume 25 Issue 12 Pages 885-889
    Published: December 15, 1997
    Released on J-STAGE: February 26, 2010
    DOIhttps://doi.org/10.2184/lsj.25.885
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    We studied a lasing characteristics of a LD pumped Tm:YAG laser in a single-mode oscillation. A maximum output power of 65mW at a wavelength 2017.8nm and a temperature of 15°C was obtained. The oscillation wavelength could be changed from 1965nm to 2030nm smoothly. The stability of the oscillation frequency was measured to be 10MHz at average of 10 mitutes.
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  • Triple-Pass Ti:sapphire Pre-Amplifier with 60dB Gain for Laser Systems Using Chirped-Pulse Amplification
    Helmut SCHILLINGER, Shuji SAKABE, Tomoyuki KUGE, Hiroki UEYAMA, Tohru ...
    1997 Volume 25 Issue 12 Pages 890-893
    Published: December 15, 1997
    Released on J-STAGE: July 30, 2010
    DOIhttps://doi.org/10.2184/lsj.25.890
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    By pumping a brewster-cut Ti:sapphire crystal from both sides with a frequency-doubled Nd:YAG laser at 6J/cm2 we achieved a single pass gain of 20dB. This allows to amplify pulses from the nano-Joule to the milli-Joule level with a triple-pass amplifier with > 60dB gain. An output energy up to 3.5mJ was measured, depending on the input energy from the oscillator/stretcher front end. The triple-pass amplifier was used in a chirped-pulse amplification terawatt system. We discuss the advantages of this approach, e.g. for the amplification of very short pulses and for the level of amplified spontaneous emission.
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  • Fundamentals on Lasers II
    Theory of Optical Resonators
    Mitsuo MAEDA
    1997 Volume 25 Issue 12 Pages 894-904
    Published: December 15, 1997
    Released on J-STAGE: February 26, 2010
    DOIhttps://doi.org/10.2184/lsj.25.894
    JOURNAL FREE ACCESS
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