レーザー研究
Online ISSN : 1349-6603
Print ISSN : 0387-0200
ISSN-L : 0387-0200
24 巻, 1 号
選択された号の論文の15件中1~15を表示しています
  • 小倉 繁太郎
    1996 年 24 巻 1 号 p. 1-2
    発行日: 1996/02/05
    公開日: 2010/02/26
    ジャーナル フリー
  • H. Angus MACLEOD
    1996 年 24 巻 1 号 p. 3-10
    発行日: 1996/02/05
    公開日: 2010/02/26
    ジャーナル フリー
    Modern design methods for optical coatings make considerable use of automatic computer methods. These have ensured that design practice remains ahead of manufacturing capabilities. Continuing increases in the number of layers in coatings that can be readily manufactured, may imply a barrier to progress in automatic methods, which will have to be overcome.
  • 吉田 國雄, 吉田 英次, 本越 伸二
    1996 年 24 巻 1 号 p. 11-17
    発行日: 1996/02/05
    公開日: 2010/02/26
    ジャーナル フリー
    Recent improvements of optical coating for high power lasers are presented. A highly damageresistant coatings were developed by using a surface prepared and super-polished substrate. Recent topics on laser-induced damage caused by nodular defects are described. Antireflection coatings using Teflon and chemical process are also shown.
  • 潟岡 泉
    1996 年 24 巻 1 号 p. 18-26
    発行日: 1996/02/05
    公開日: 2010/02/26
    ジャーナル フリー
    Construction of interferometric gravitational wave antennas has led to paying attention to ultralow-loss mirrors. The loss of these mirrors reaches a level of ppm (at 1.06 μm) nowadays. The development of these kind of mirrors is based on the technology for mirrors of Ring Laser Gyroscope (RLG). Such ultralow-loss was realized by the hypersmooth polishing technology with the accurate measurement of surface roughness and by the advanced ion beam sputtering deposition technology. This paper reviews current progress in ultralow-loss mirrors through the development of RLGs, gravitational antennas and soft x-ray optics.
  • Ian M. THOMAS
    1996 年 24 巻 1 号 p. 27-35
    発行日: 1996/02/05
    公開日: 2010/02/26
    ジャーナル フリー
    The sol-gel process is a versatile procedure used for the preparation of a large variety of oxide products, including optical coatings. Investigations into coatings for laser systems have been ongoing for nearly 30 years. Earlier work suffered from inconsistant damage threshold levels and expensive processing costs. Recent improvements, however, have resulted in the process being particularly successful in the preparation of quarterwave porous silica antireflection (AR) coatings for use in high power fusion laser systems. The laser damage thresholds are two to three times higher than coatings prepared by other methods. More recently, investigations into quarterwave, high-low index, multilayer, high-reflective (HR) coatings have resulted in products which, while not as superior as their AR equivalents, have compared favorably with competitive materials.
    The process is particularly suitable for large substrates and has the potential of economically producing the large number of optical coatings required for the next generation of fusion lasers.
  • 山下 幹雄
    1996 年 24 巻 1 号 p. 36-47
    発行日: 1996/02/05
    公開日: 2010/02/26
    ジャーナル フリー
    An application of dielectric multilayer mirrors for chirp compensation is reviewed on femtosecond pulse generation from a colliding-pulse mode-locked (CPM) dye laser and a Kerrlens mode-locked (KLM) Ti:sapphire laser. The principle of a chirp compensation technique, the design of chirp compensation cavity-mirrors, and the experimental results for their femtosecond pulse lasers are described in detail. Furthermore, we review a theoretical proposal of ultafast optical limiting and switching applications of nonlinear dielectric multilayer elements as one-dimensional photonic band gap materials, and an experimental study of tunneling of femtosecond optical pulses through photonic band gaps.
  • Masahito NIIBE, Shigetaro OGURA, Masami TSUKAMOTO, Takashi IIZUKA, Aki ...
    1996 年 24 巻 1 号 p. 48-60
    発行日: 1996/02/05
    公開日: 2010/02/26
    ジャーナル フリー
    We review first the state of the art fabrication techniques for normal incidence multilayer mirrors, and then discuss the problems such as columnar structure, thermal stability, mechanical stress, focusing properties of multilayer mirrors, film thickness distribution, and finally the applications of multilayer mirrors for the x-ray lasers and x-ray projection lithography, using mainly the data experimentally obtained.
  • 青木 智則
    1996 年 24 巻 1 号 p. 61-73
    発行日: 1996/02/05
    公開日: 2010/02/26
    ジャーナル フリー
    Most of optical coatings have been made by conventional vacuum evaporation. The recent progress of coating technology requests to study the starting materials. No systematic study has been yet done to prove the relationship between optical coatings and their starting materials. This paper introduces the important points of making starting materials and related evaporation processes. It is important to know that the particle size distribution and purity in raw materials. The stable optical coatings require the stable starting materials and relevant evaporation processes. First some evaporation materials, important to produce laser mirrors, for example TiO2, Ta2O5 and SiO2, are described here. Then the relationship between laser damage threshold and starting material of HfO2 is described too.
  • 伊沢 孝男, 前田 正晴, 山村 史彦, 木村 信二, 内村 龍二, 猿倉 信彦, 瀬川 勇三郎
    1996 年 24 巻 1 号 p. 74-80
    発行日: 1996/02/05
    公開日: 2010/02/26
    ジャーナル フリー
    In widely tunable lasers such as Ti:Sapphire and Cr:LiSAF lasers, the tuning region is limited by the bandwidth of the mirror coatings rather than the potential tuning region of the laser material itself. To overcome these problems, we have been developing extremely broadband, lowloss mirrors which enable full range tuning of such tunable lasers.
    In this paper, we report the results for near infrared broadband mirrors which cover the entire tuning range of Ti:Sapphire and Cr:LiSAF lasers. These mirrors have reflectances of 99.85% to 99.95 % for wavelengths of 680 to 1060 nm.
  • Cheng-Chung LEE, Yuh-Hui LAI, Jin-Cherng HSU
    1996 年 24 巻 1 号 p. 81-87
    発行日: 1996/02/05
    公開日: 2010/02/26
    ジャーナル フリー
    Ion-beam-assisted deposition (IAD) gold film and its protective layers used as laser mirrors and reflectors for near IR and IR have been discussed. In order to have high reflectance the gold film is deposited without heating or ion beam assistance. To avoid the mirror from degradation by moisture and having better abrasion resistance, HfO2 film was deposited with ion beam assistance as a protective layer. Depend on the application, different glue layer between a substrate and gold film is necessary. The reflectance of a laser mirror can be increased by coating some pairs of enhanced dielectric layers on the top of the gold film.
  • 田本 純一, 岡田 勝久
    1996 年 24 巻 1 号 p. 88-93
    発行日: 1996/02/05
    公開日: 2010/02/26
    ジャーナル フリー
    For optical thin film production by a sputtering method, it is common to use RF or DC reactive sputtering. Since during deposition sputtering and reactive processes are operated simultaneously, a substrate temperature rise is caused. Also the deposition rate is very low because metal atoms sputtered need enough time for sufficient oxidation. For solving these problems, we separated the deposition process into two stages, i.e., sputtering and reactive processes. As result of these two successively separated processes, the deposition rate for metal oxides can be as similar to that of pure metals with no substrate temperature rise. This is completely different from that during RF sputtering. This new type DC reactive sputtering method is called Two Stages High Rate Sputtering, Divided Sputtering Prosess and Reactive process (TSH Sputtering Method). This paper describes the deposition principle and reports the improvements of refractive index, deposition rate and substrate temperature rise. Finally the antireflection coatings produced by the TSH sputtering method as an example of multilayer, and their spectral characteristics and reproducibility are represented.
  • François FLORY, Hervé RIGNEAULT, J. MASSANEDA, Serge MON ...
    1996 年 24 巻 1 号 p. 94-102
    発行日: 1996/02/05
    公開日: 2010/02/26
    ジャーナル フリー
    Guided wave techniques are powerful to study the properties of different optical coatings. The latest results are presented to illustrate the interest of these techniques: the dependence on ion energy of the anisotropy of ion assisted TiO2 films is given; the measurement of losses during propagation permits to study the origin of losses in multilayer coatings and in particular to demonstrate that absorbing transition layers have to be introduced in the model; properties of ion implanted Ta2O5 layers are also investigated. The refractive index profile of Ta2O5 layers implanted with Ti is determined by using the m-line technique; coupling a pump beam at 488 nm in different guided modes, the photoluminescent properties around 1.53 mm of Er implanted Ta2O5 layers are also shown.
  • Chang Kwon HWANGBO, Hyun Ju CHO
    1996 年 24 巻 1 号 p. 103-109
    発行日: 1996/02/05
    公開日: 2010/02/26
    ジャーナル フリー
    TiO2 thin films were deposited by Ar ion beam assistance of Kaufman and gridless ion sources. Optical and structural properties of IAD TiO2 thin films and comparison between two types of sources are described. The result shows that Ar IAD by both ion sources improves the packing density and refractive index of TiO2 thin films. The high energy Ar ion beam of the Kaufman ion source induces an increase in extinction coefficient as the ion current density increases, while the gridless ion source results in a decrease in extinction coefficient. The crystal-line structure of conventional and Kaufman-IAD TiO2 films is amorphous whereas some gridless-IAD TiO2 films show anatase phases as the ion current density increases.
  • Qi TANG, Sigetaro OGURA, Kazuo KIKUCHI, Nobuyuki HIGASHI
    1996 年 24 巻 1 号 p. 110-117
    発行日: 1996/02/05
    公開日: 2010/02/26
    ジャーナル フリー
    Ion assisted deposition has been applied widely in present optical industry, to obtain more dense films, but it is often required to attain longer filament lifetime of the ion source particularly in the case of successively reactive oxidation processes under an additional oxygen gas inlet such as in oxide films for laser mirror application. It is the reason why radio frequency ion source is keenly interested at the present moment. Therefore we have investigated the optical and structural properties of Ta2O5 films as the functions of ion energy (300-750eV), substrate temperature (ambient or 300°C ), arrival ratio (0.2-0.8 atoms/ion), and providing the oxygen ions by RF ion source to bombardment. Typically, Ta2O5 thin films with refractive index larger than 2.25 and extinction coefficient less than 6×10-4 in visible region have been obtained under the conditions of oxygen ion energy of 500 eV, at the substrate temperature of 300°Cand with the arrival ratio of 0.4 atoms/ion. Their cross sections of the films are shown the amorphous-like, amorphous columnar, and polycrystalline columnar structures by SEM and XRD. Several results of surface roughness of these films by AFM and OP, and the packing densities of these films by spectrometer (OPM-V1) are also presented.
  • Structures and Properties of Inhomogeneous Films
    Itaru TAKAGI, Shigetaro OGURA
    1996 年 24 巻 1 号 p. 118-124
    発行日: 1996/02/05
    公開日: 2010/02/26
    ジャーナル フリー
    It is well known that titanium dioxide films, deposited by conventional electron beam gun, are homogeneous. Controlling acceleration voltage and current applied to the ion gun continuously during ion assisted deposition by additional Kaufman type ion gun, large degree of intentionally produced inhomogeneous titanium dioxide films are obtained. There exist both types of positively and negatively inhomogeneous films. These optical properties and relationships among their film structures are investigated by the terms of surface topology by surface profilometer and cross-sectional view by scanning electron microscope. Positively inhomogeneous films show a linear refractive index change along film thickness, but the negatively inhomogeneous films possess nonlinear nature and still need to find the appropriate deposition condition, which gives a linear refractive index profile. For this purpose, the films are further characterized by an ellipsometer. Finally the results are compared with those obtained from the macroscopic structure model for the inhomogeneous films.
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