JPH109811A - Coherent divergence interference method - Google Patents

Coherent divergence interference method

Info

Publication number
JPH109811A
JPH109811A JP8196862A JP19686296A JPH109811A JP H109811 A JPH109811 A JP H109811A JP 8196862 A JP8196862 A JP 8196862A JP 19686296 A JP19686296 A JP 19686296A JP H109811 A JPH109811 A JP H109811A
Authority
JP
Japan
Prior art keywords
light
laser
coherent
solute
transparent body
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
JP8196862A
Other languages
Japanese (ja)
Other versions
JP4042068B2 (en
Inventor
Masao Umemoto
雅夫 梅本
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Priority to JP19686296A priority Critical patent/JP4042068B2/en
Publication of JPH109811A publication Critical patent/JPH109811A/en
Application granted granted Critical
Publication of JP4042068B2 publication Critical patent/JP4042068B2/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Classifications

    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/171Systems in which incident light is modified in accordance with the properties of the material investigated with calorimetric detection, e.g. with thermal lens detection
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/41Refractivity; Phase-affecting properties, e.g. optical path length
    • G01N21/45Refractivity; Phase-affecting properties, e.g. optical path length using interferometric methods; using Schlieren methods

Landscapes

  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Instruments For Measurement Of Length By Optical Means (AREA)
  • Length Measuring Devices By Optical Means (AREA)
  • Investigating Or Analysing Materials By Optical Means (AREA)
  • Photometry And Measurement Of Optical Pulse Characteristics (AREA)

Abstract

PROBLEM TO BE SOLVED: To obtain a strong coherent divergence light, excellent in coherency by varying the refractive index of a transparent body locally and irradiating the transparent body with a laser light. SOLUTION: When a transparent body (transparent plate) of glass, quartz, optical crystal, transparent plastic, etc., is varies physically by making the micropoints (several tens μm) irregular locally, or injecting a micro quantity of liquid or bubble in order to after the density and to cause an optical distortion, the refractive index is varied to induce a strong coherent divergence light in the irradiated laser light. When an absorption cell (measuring cell) having four transparent sides is filled with a water dispersed with latex particles of about 0.3μm, and irradiated with a pumping laser (KGW laser, etc.) from a direction perpendicular to the optical axis of a He-Ne laser for the purpose, a coherent divergence light is generated in synchronism with a pulse from the pumping laser and a significant fluctuation of interference fringe can be observed on a screen in synchronism with the pulse from the pumping laser.

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【0001】[0001]

【産業上の利用分野】本発明は基本原理であるコヒーレ
ント発散光を得る方法と、それを用いた高感度な干渉計
熱検出法及び溶質濃度測定法に関する。
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for obtaining coherent divergent light, which is a basic principle, and to a highly sensitive interferometer heat detection method and solute concentration measurement method using the same.

【0002】[0002]

【従来の技術】従来、コヒーレントな発散光を得る方法
としては、ピンポイント法、ピンホール法等がある。前
者はナイフエッジ、細線の先端にレーザー光を照射する
方法であるが、可干渉性(コヒーレンス)が劣る。ピン
ホール法はピンホールをあけた面にレーザー光を照射す
ると、ピンホールを通過した光は可干渉性に優れた光が
得られる。しかし、この場合の回折光の強度は弱い。以
上のように、従来法の発散光はほとんど役に立たない。
干渉計は、干渉を利用して位置、形状、変位等を高感
度、高精度に計測できる計測器である。干渉計にはマイ
ケルソン干渉計、マッハーツェンダ干渉計、ファブリペ
ロー干渉計等が有名である。特徴、目的に応じてトワイ
マン−グリーン干渉計、フィゾー干渉計、斜入射干渉
計、ヘテロダイン干渉計、ホログラフィー干渉計等があ
る。これらの干渉計は基本的には、光源から発せられた
光波をハーフミラー等で分割し、一方を精巧なミラーに
当て、他方の参照波と重ね合わせて干渉縞を得ることを
原理としている。
2. Description of the Related Art Conventionally, methods for obtaining coherent divergent light include a pinpoint method and a pinhole method. The former is a method of irradiating a knife edge or the tip of a fine wire with a laser beam, but has poor coherence. In the pinhole method, when a laser beam is applied to a surface where a pinhole is formed, light having excellent coherence can be obtained from light passing through the pinhole. However, the intensity of the diffracted light in this case is weak. As described above, the divergent light of the conventional method is almost useless.
An interferometer is a measuring instrument that can measure position, shape, displacement, and the like with high sensitivity and high accuracy using interference. Famous interferometers include a Michelson interferometer, a Mach-Zehnder interferometer, and a Fabry-Perot interferometer. There are a Twyman-Green interferometer, a Fizeau interferometer, an oblique incidence interferometer, a heterodyne interferometer, a holographic interferometer, and the like according to features and purposes. Basically, these interferometers are based on the principle that an optical wave emitted from a light source is split by a half mirror or the like, one of which is applied to a sophisticated mirror, and the other is superposed on a reference wave to obtain interference fringes.

【0003】[0003]

【発明が解決しようとする課題】本発明では、可干渉性
に優れた強力な発散光を得る方法について述べる。これ
は、様々な応用が可能な極めて有効な技術である。本発
明では、ハーフミラーを用いることなく光源からの光の
一部をコヒーレントに発散させてこれを参照光とするた
め、精巧なミラーを用いることなく(用いる方式も可
能)物体の変位が測定できる。従来の干渉法では適用困
難な、散乱光、拡散光等、種々の二次光の情報をも測定
できるような干渉法の実用化を目的としている。
In the present invention, a method for obtaining a strong divergent light with excellent coherence will be described. This is a very effective technique that can be used in various applications. In the present invention, a part of the light from the light source is coherently diverged without using a half mirror, and this is used as a reference light. Therefore, the displacement of the object can be measured without using a sophisticated mirror (a method can be used). . An object of the present invention is to commercialize an interferometry that can measure information of various kinds of secondary light such as scattered light and diffused light, which is difficult to apply with the conventional interferometry.

【0004】[0004]

【課題を解決するための手段】本発明は、レーザー光を
コヒーレントに発散させ、その発散光を参照光とし、別
に同一波長のレーザー光を対象物に照射し、その二次光
(二次光とは、散乱光、拡散光、反射光、屈折光、回折
光等をさす)と参照光とを重ね合わせる干渉法である。
コヒーレント(可干渉)発散光の様子を図1に示す。こ
れからわかるように、単なる散乱光(スペックル)とコ
ヒーレント発散光は全く異なり、コヒーレント発散光が
生じた時のみ干渉縞が現れる。二次光を得るレーザー
と、コヒーレント発散光を得るためのレーザーとは別で
もよいが、簡略のために同じものとすることも出来る。
ここでいうレーザーとはHe−Neレーザー、半導体レ
ーザー、ガスレーザー、アルゴンレーザー、色素レーザ
ー、Ni−Cdレーザー、YAGレーザー、KGWレー
ザー等で、連続光でも良く、パルス光でもよい。コヒー
レント発散光を得るには、 (1)ガラス、石英、光学結晶、透明プラスチック(ア
クリル、ポリメタアルリル酸メチル、ポリエチレンテレ
フタレートなど)等の透明板に微粒子を付着させ、それ
による散乱光をもって拡散光とする。微粒子はおよそ数
十μm程度がよい。透明板を傾斜させると良い結果が得
られる。適切な微粒子を透明板に付着させた後、ガラス
又は石英の薄板を上にのせ、接着剤を周囲につけて固定
するのがよい。 (2)透明物体の微小点(数十μm)を物理的に変化さ
せることにより、光はコヒーレントに発散する。例え
ば、局所的に凹凸とする、微量の液体や気泡を入れてお
く、局所的に密度をかえるなど、光学的ゆがみを起こさ
せる方法によって変化させる。アクリル板に付着させ
た、目では見えない直径数十μmのラテックス粒子にレ
ーザー光を集光させ、コヒーレント発散光が生じ、それ
と粒子による散乱光との干渉縞ができる様子の模式図を
図2に示す。また、透明な水晶、ガラス、石英ガラス、
透明光学結晶(LiNbO,LiTaOなど)に含
まれる数十μmの不純物(無機又は有機)によるレーザ
ー光の発散を利用することもできる。水晶、石英は多面
カットが可能なため、カッティングにより、微小点を光
学的特異点とすることができる。又、結晶化過程で微小
点において結晶軸が変化することがあるのでこれを利用
する。(3)粒径が数十から数百nmで、できる限り単
一径粒子の数を一定数以上にするとその各粒子からの散
乱光がコヒーレントな拡散光となるのでそれと利用する
方法もある。(4)結晶質透明板に、数十μmに径を絞
った強いレーザー光を照射すると、局所的に非晶質とな
る。逆に非晶質透明板は局所的に結晶質となる。これを
利用して屈折率を局所的に変化させることができ、コヒ
ーレント発散光が得られる。一般に発散光を得るには照
射光をレンズで絞り、その焦点付近で行うのがよい。発
散光を得る照射光と、二次光を得る照射光とは、同じで
あっても、異なっていてもよい。異なっている方式で
は、照射光とは別に照射光の光軸とは離れてはいるが、
近い光軸をもつ光を照射し、これを上述の方法で拡散さ
せる方式をいう。これには種々の型がある。すなわち、
(ア)第2光源を照射光とは全く異なる光源とする。
(イ)第2光源光は、レーザーのような強い照射光源を
前方のレンズ面、ガラス面等で反射させ、それを更に鏡
面等で反射させるものである。レーザー光の集光レンズ
あるいは試料を入れる石英セルでレーザー光の一部を反
射させ、それをレーザー出射口に入れレーザー出射レン
ズで反射させる方式が最も単純である。(ウ)複屈折結
晶を用いて2つの光に分け、一方を照射光とし他方を上
述の種々の方法で拡散させて拡散光とする。このような
結晶には、偏光プリズム、ウォラストンプリズム、サバ
ール板、ニコルプリズム等がある。干渉縞の可視度を大
きくし、高感度を得るにはコヒーレント発散光の強度を
大きくしなければならない。また、光学配置は単純であ
ることが望ましい。本発明は干渉法であるので、生じた
干渉縞を種々の方法で測定する必要がある。干渉縞解折
には、デジタル画像処理装置を用いればよい。干渉光を
横ずらし方向と直角方向に微小なくさび角を付けたくさ
びガラスに入射させる光学的コントラスト法を適用する
ことにより、干渉縞のコントラストが格段に向上しSN
比を飛躍的に大きくできる。検出器には各種のイメージ
センサーやCCDカメラ、半導体位置検出器等が用いら
れる。しかし、このような2次元情報をとらえる方式と
は別に光検出器(フォトダイオート、光電子増陪管、ス
トリーク管等)の前にピンホールを置き、ピンホールを
通過する干渉縞の明暗変化を検出することができる。ピ
ンホールは必ずしも1点である必要はなく、検出面上に
数点ある方がわずかな変化をとらえることが可能であ
る。粒子が動的である場合、干渉縞は移動する結果、あ
る周波数の振動信号が得られるので、それをレコーダー
に記録するか、周波数分析器、周波数トラッカー、周波
数カウンター、あるいは高速フーリエ変換分析器(FF
T)、光子相関器等で信号解析を行うことができる。一
定の特定周波数の信号であれば、位相検波回路と増幅に
より微弱信号の測定が可能である。試料が静的である場
合には、従来の干渉法と同様に位相変調干渉法、ヘテロ
ダイン干渉法、半導体レーザーを用いる周波数変調干渉
法等を応用することができる。コヒーレント発散光と光
散乱光とにより、光電面で、光混合ビート信号を得るヘ
テロダイン光混合分光法は、本発明のコヒーレント発散
光をうまく活かした分光法といえる。また、ロックイン
増幅を適用してSN比を上げ、高感度化を図ることがで
きる。すなわち、照射光又は発散光のいずれか一方をチ
ョッパーで断続するか又はパルス発光させると、干渉縞
が断続的に出現したり消失したりするのでこれをロック
イン増幅し検出する方法である。これによりバックグラ
ウンドが消去できる。以上、本発明の構成を用い、流
速、変位、粒径等を高感度で検出できる。粒径を測定す
るには本発明の構成に、従来の種々の手法(例えば、化
学工学47巻9号、18〜22ページ、1983年)を
適用する。本発明の干渉法の応用として、次のような実
施態様が上げられる。測定セル内に光散乱粒子を入れる
ことにより、照射光は粒子により散乱される。この散乱
光はコヒーレント発散光と干渉し、前方面に干渉縞を生
じる。これを定量することにより、散乱光及びその実体
である粒子を測定することができる。この原理の応用と
して、測定セルを熱吸収体とすることにより、熱又は赤
外線そのものを測定できる。さらに別の応用として、測
定セル及び光散乱体は熱を吸収しない性質のものとし、
溶質が吸収する光を照射光とは別に入射することにより
溶質の光吸収に基づく温度上昇のが生じる。その結果、
光散乱体に動揺が生じるのでそれを検出することによ
り、溶質濃度が測定できる。逆に光散乱体のみを光吸収
体とすることにより、光散乱体濃度を測定できる。 (1)温度傾斜光散乱粒子測定法: 光散乱粒子にはラ
テックス、無機物、金属、カーボン等のコロイド粒子の
他、エーロゾル等があり、それを含む測定セル内に温度
傾斜を生じさせることにより粒子の移動が生じ干渉縞が
移動する。この信号はある周波数をもった振動となるの
で、前述のFFT分析器等で解析し、粒径、粒子数等を
測定する。測定セル内に温度傾斜を生じさせる方法とし
ては、ペルチエ素子をセル面につける方法、ヒーター加
熱による方法、熱線照射法などがある。粒子数が多い
程、周波数は増大する。また、粒径が大きい程振動強度
は増大する。 (2)熱検出器: 光散乱粒子を入れた測定セルにおい
て、光軸通過面とは異なる面を熱吸収体(黒色でかつ金
属等の熱伝導体)とすることにより、熱を高感度に吸収
させ、もってセル内の光散乱体の動揺を引き起こし、そ
れによる干渉縞の変化を測定すれば高感度な熱検出法と
なる。測定セル面を熱吸収体とする代わりに光散乱体
(黒色コロイド、金属コロイド)を熱吸収体とするか、
溶媒(赤外域に強い吸収バンドを有する溶媒なら何でも
よい)を熱吸収体としてもよい。 (3)光熱変換測定法: 照射光とは別に溶媒に溶けた
溶質又はコロイド粒子そのものが吸収する光を照射すれ
ば、溶媒またはコロイドの温度が上昇し、その結果、コ
ロイドの運動が誘起され、コロイドによる干渉縞が移動
するので、それを測定し、溶質又はコロイド濃度を求め
ることが出来る。励起光源などには各種レーザーの他、
キセノンランプ、ハロゲンランプ等を用いることができ
る。この方法の原理はいわゆる熱レンズ法、又は光熱変
換分光法に類似するが、これらは温度上昇による屈折率
変化を測定するものであるのに対し、本発明では温度上
昇によるコロイド粒子の運動を干渉縞の変化としてとら
えるところが異なる。干渉縞は、屈折率変化と異なり、
わずかな変化をもとらえることができるので極めて高感
度となる。
According to the present invention, a laser beam is diverged coherently, the divergent beam is used as a reference beam, and a laser beam of the same wavelength is radiated to an object separately. The term “scattered light, diffused light, reflected light, refracted light, diffracted light, or the like” refers to an interference method in which reference light is superimposed.
FIG. 1 shows a state of coherent (coherent) divergent light. As can be seen, mere scattered light (speckle) and coherent divergent light are completely different, and interference fringes appear only when coherent divergent light occurs. The laser for obtaining the secondary light and the laser for obtaining the coherent divergent light may be different, but may be the same for simplicity.
The laser here is a He-Ne laser, a semiconductor laser, a gas laser, an argon laser, a dye laser, a Ni-Cd laser, a YAG laser, a KGW laser, or the like, and may be a continuous light or a pulsed light. To obtain coherent divergent light: (1) Fine particles are attached to a transparent plate made of glass, quartz, optical crystal, transparent plastic (acryl, polymethyl methyl acrylate, polyethylene terephthalate, etc.), and the scattered light is diffused. . The size of the fine particles is preferably about several tens μm. Good results can be obtained by tilting the transparent plate. After attaching the appropriate fine particles to the transparent plate, a thin plate of glass or quartz may be placed on top, and an adhesive may be applied around and fixed. (2) Light is coherently diverged by physically changing minute points (several tens of μm) of the transparent object. For example, it is changed by a method of causing optical distortion, such as locally forming unevenness, storing a small amount of liquid or air bubbles, or locally changing the density. FIG. 2 is a schematic view showing a state in which laser light is focused on latex particles having a diameter of several tens of μm, which are attached to an acrylic plate and are invisible, and coherent divergent light is generated. Shown in Also, transparent crystal, glass, quartz glass,
Laser light divergence due to impurities (inorganic or organic) of several tens of μm contained in transparent optical crystals (LiNbO 3 , LiTaO 3, etc.) can also be used. Quartz and quartz can be cut on multiple sides, so that micropoints can be set as optical singularities by cutting. In addition, since the crystal axis may change at a minute point during the crystallization process, this is utilized. (3) If the particle size is several tens to several hundreds nm and the number of single-diameter particles is made a certain number or more as much as possible, the scattered light from each particle becomes coherent diffused light. (4) When the crystalline transparent plate is irradiated with strong laser light having a diameter of several tens of μm, the crystalline transparent plate becomes locally amorphous. Conversely, the amorphous transparent plate becomes locally crystalline. By utilizing this, the refractive index can be locally changed, and coherent divergent light can be obtained. Generally, in order to obtain divergent light, it is preferable to irradiate the irradiation light with a lens and perform it near the focal point. The irradiation light for obtaining divergent light and the irradiation light for obtaining secondary light may be the same or different. In a different method, apart from the optical axis of the irradiation light separately from the irradiation light,
A method of irradiating light having a close optical axis and diffusing the light by the above-described method. There are various types of this. That is,
(A) The second light source is a light source completely different from the irradiation light.
(A) The second light source is a light that reflects a strong irradiation light source such as a laser on a front lens surface, a glass surface or the like, and further reflects it on a mirror surface or the like. The simplest method is that a part of the laser light is reflected by a condenser lens for the laser light or a quartz cell into which the sample is put, and then the laser light is put into a laser emission port and reflected by the laser emission lens. (C) The light is divided into two lights by using a birefringent crystal, and one is irradiated light and the other is diffused by the above-mentioned various methods to be diffused light. Such crystals include polarizing prisms, Wollaston prisms, Savart plates, Nicol prisms and the like. In order to increase the visibility of interference fringes and obtain high sensitivity, the intensity of coherent divergent light must be increased. It is also desirable that the optical arrangement be simple. Since the present invention is an interference method, it is necessary to measure the generated interference fringes by various methods. A digital image processing device may be used for the interference fringe analysis. By applying an optical contrast method in which the interference light is made incident on wedge glass having a small wedge angle in the direction perpendicular to the lateral shift direction, the contrast of the interference fringes is remarkably improved.
The ratio can be greatly increased. As the detector, various image sensors, CCD cameras, semiconductor position detectors, and the like are used. However, apart from such a method of capturing two-dimensional information, a pinhole is placed in front of a photodetector (photo dye auto, photomultiplier tube, streak tube, etc.), and the light and dark changes of interference fringes passing through the pinhole are measured. Can be detected. It is not always necessary that the number of pinholes be one, and a slight change can be detected when there are several pinholes on the detection surface. If the particles are dynamic, the interference fringes will move, resulting in a vibration signal at a certain frequency, which can be recorded on a recorder, or used as a frequency analyzer, frequency tracker, frequency counter, or fast Fourier transform analyzer ( FF
T), signal analysis can be performed by a photon correlator or the like. If the signal has a specific frequency, a weak signal can be measured by a phase detection circuit and amplification. When the sample is static, a phase modulation interferometer, a heterodyne interferometer, a frequency modulation interferometer using a semiconductor laser, or the like can be applied as in the conventional interferometer. Heterodyne light mixing spectroscopy, in which a light mixing beat signal is obtained on the photocathode by using the coherent divergent light and the light scattered light, can be said to be a spectroscopic method that makes good use of the coherent divergent light of the present invention. In addition, the S / N ratio can be increased by applying lock-in amplification, and high sensitivity can be achieved. That is, when either the irradiation light or the diverging light is intermittently or pulse-emitted by the chopper, the interference fringes appear or disappear intermittently, and this is a method of lock-in amplification and detection. Thereby, the background can be erased. As described above, the flow rate, the displacement, the particle size, and the like can be detected with high sensitivity by using the configuration of the present invention. In order to measure the particle size, various conventional techniques (for example, Chemical Engineering, Vol. 47, No. 9, pp. 18-22, 1983) are applied to the constitution of the present invention. As an application of the interferometry of the present invention, the following embodiments are given. By placing the light scattering particles in the measuring cell, the illuminating light is scattered by the particles. This scattered light interferes with the coherent divergent light and produces interference fringes on the front surface. By quantifying this, scattered light and its actual particles can be measured. As an application of this principle, heat or infrared light itself can be measured by using a measurement cell as a heat absorber. As still another application, the measuring cell and the light scatterer have a property of not absorbing heat,
When the light absorbed by the solute is incident separately from the irradiation light, a temperature rise occurs due to the light absorption of the solute. as a result,
Since the light scatterer is shaken, the concentration of the solute can be measured by detecting the fluctuation. Conversely, by using only the light scatterer as the light absorber, the concentration of the light scatterer can be measured. (1) Temperature gradient light scattering particle measurement method: Light scattering particles include latex, colloidal particles of inorganic substances, metals, carbon, and the like, as well as aerosols. Particles are generated by causing a temperature gradient in a measurement cell containing the particles. And the interference fringes move. Since this signal becomes a vibration having a certain frequency, it is analyzed by the above-described FFT analyzer or the like, and the particle size, the number of particles, and the like are measured. As a method of causing a temperature gradient in the measurement cell, there are a method of attaching a Peltier element to the cell surface, a method of heating with a heater, a heat ray irradiation method, and the like. The frequency increases as the number of particles increases. Also, the vibration intensity increases as the particle size increases. (2) Heat detector: In a measurement cell containing light scattering particles, a heat absorber (black and a heat conductor such as metal) is used as a heat absorber on a surface different from the optical axis passing surface, so that heat can be detected with high sensitivity. Absorption causes the light scatterer in the cell to fluctuate, and a change in interference fringes caused by the fluctuation is measured to provide a highly sensitive heat detection method. Instead of using a measurement cell surface as a heat absorber, use a light scatterer (black colloid, metal colloid) as a heat absorber,
A solvent (any solvent having a strong absorption band in the infrared region) may be used as the heat absorber. (3) Photothermal conversion measurement method: When irradiated with light that is absorbed by the solute or colloid particles themselves dissolved in the solvent separately from the irradiation light, the temperature of the solvent or colloid rises, and as a result, the movement of the colloid is induced, Since the interference fringe due to the colloid moves, it can be measured to determine the solute or colloid concentration. Excitation light source, etc.
A xenon lamp, a halogen lamp, or the like can be used. The principle of this method is similar to the so-called thermal lens method or photothermal conversion spectroscopy. The difference is that they are perceived as changes in stripes. Interference fringes, unlike refractive index changes,
Very small changes can be detected, resulting in extremely high sensitivity.

【本発明の効果】本発明の実用上における効果は次の点
に集約される。 (1)本発明では、光軸上にある粒子の光散乱が十分で
あれば、たった1個であっても干渉縞が生成するので、
たった1個の粒子でも検出できる。 (2)本発明では、コントラストの強い干渉縞を生成す
ることが可能なため、測定対象の微小な変化による干渉
縞の変化を検出できる。したがって、極めて高感度であ
り、光散乱法の約100倍の感度が得られる(図3)。 (3)粒径、粒子数、変位、光散乱等の物理量を光強度
としてではなく干渉縞変化としてとらえるため種々の検
出原理が応用でき、選択的かつ高感度が得られる。 (4)コヒーレント発散光を得るための光学系は極めて
単純なため装置をコンパクトにできる。 (5)コヒーレント発散光は、レーザー光を一点に集光
して得られるためピンホール、コリメータレンズ等を用
いて得られる参照光と異なり強度が極めて大きいため、
高い感度が得られる。
The effects of the present invention in practical use are summarized in the following points. (1) In the present invention, if light scattering of particles on the optical axis is sufficient, interference fringes are generated even with only one particle.
Even a single particle can be detected. (2) According to the present invention, it is possible to generate an interference fringe having a high contrast, so that it is possible to detect a change in the interference fringe due to a minute change in the measurement target. Therefore, the sensitivity is extremely high, and a sensitivity about 100 times that of the light scattering method is obtained (FIG. 3). (3) Since physical quantities such as particle size, number of particles, displacement, and light scattering are not regarded as light intensity but as changes in interference fringes, various detection principles can be applied, and selective and high sensitivity can be obtained. (4) Since the optical system for obtaining coherent divergent light is extremely simple, the apparatus can be made compact. (5) Since the coherent divergent light is obtained by condensing the laser light at one point, unlike a reference light obtained using a pinhole, a collimator lens, or the like, the intensity is extremely large.
High sensitivity is obtained.

【実施例1】図4に示すように、5mWヘリウムネオン
レーザー(JAPAN LASERCORP.Mode
lJLH−3PS−A)の前方40mmに凸レンズ(f
=30mm)を置き、その前方10mmに径1mmのピ
ンホールを置く。さらに、ピンホールの前方約20〜4
0mmに光路長10mmの石英吸収セルを置き、吸収セ
ルの前方450mmに径1mmのピンホール及び光電子
増倍管(PMT)を置く。ピンホール及びPMTをはず
し、前方100cmに置いたスクリーンを見ながら吸収
セルを少しずつ傾け、スクリーンが最も明るくなり、か
つ、大きな空間周波数の干渉縞(これは、セルによる干
渉縞と思われる)がみえる角度でセルを固定する。これ
は、セルの表面に付着させた微小粒子(ラテックス)
が、レーザー光を散乱し、コヒーレント発散が生じる
が、それは数十μmという微小点で生じるため見つけ難
い。そこで、セルを傾けることにより、光軸のセル上の
位置を微妙に変化させうることを利用して発散点を見つ
けるためである。この状態で、吸収セルに0.1μmの
ミリポアフィルターろ過した水を入れスクリーンをよく
観察すると、わずかな干渉縞のゆらぎを認めた。次に、
ピンホール及びPMTを置き、高さを干渉縞のゆらぐ位
置に調節し、かつ干渉縞の暗部がピンホールにくるよう
にする。レコーダーレンジを20mVとし、ゆらぎの大
きさを測定した。比較のために吸収セルの傾きを戻し垂
直に立てて、コヒーレント散乱がおきないようにし、さ
らにピンホールとPMTをセルから120mmの位置ま
で近づけて光散乱光を測定した。図2に示すように、光
散乱はセルに4倍近いにもかかわらず信号は全く観察さ
れていないが本発明の干渉法では、0.1μmフィルタ
ーろ過した純水中のわずかな微粒子が高感度に観察され
ている。信号が振動として観察されているのは、粒子の
運動によるものと思われる。
EXAMPLE 1 As shown in FIG. 4, a 5 mW helium neon laser (JAPAN LASER CORP. Mode) was used.
1JLH-3PS-A), a convex lens (f
= 30 mm), and a pinhole with a diameter of 1 mm is placed 10 mm in front of it. Furthermore, about 20-4 in front of the pinhole
A quartz absorption cell having an optical path length of 10 mm is placed at 0 mm, and a pinhole having a diameter of 1 mm and a photomultiplier tube (PMT) are placed 450 mm in front of the absorption cell. Remove the pinhole and PMT, tilt the absorption cell little by little while looking at the screen placed 100 cm in front, and the screen becomes the brightest, and interference fringes of large spatial frequency (this seems to be interference fringes due to cells) Fix the cell at a visible angle. This is the fine particles (latex) attached to the cell surface
However, the laser light is scattered and coherent divergence occurs, but it is hard to find because it occurs at a minute point of several tens of μm. Therefore, the divergence point is found by utilizing the fact that the position of the optical axis on the cell can be slightly changed by tilting the cell. In this state, water filtered through a 0.1 μm millipore filter was put into the absorption cell, and the screen was carefully observed. As a result, slight fluctuation of interference fringes was observed. next,
The pinhole and the PMT are placed, the height is adjusted to the position where the interference fringes fluctuate, and the dark portion of the interference fringes is brought to the pinhole. The recorder range was set to 20 mV, and the magnitude of fluctuation was measured. For comparison, the absorption cell was tilted back and set up vertically to prevent coherent scattering, and the pinhole and PMT were moved closer to the position 120 mm from the cell to measure light scattered light. As shown in FIG. 2, no signal was observed at all even though the light scattering was nearly four times that of the cell. However, in the interferometry of the present invention, the fine particles in pure water filtered with a 0.1 μm filter were highly sensitive. Has been observed. It is likely that the signal was observed as a vibration due to the motion of the particles.

【実施例2】実施例1の光学系において、それぞれ石英
セルを傾けたりすることなく微粒子によるコヒーレント
拡散を利用する方法を示す。すなわち、石英セルを垂直
に立てた状態でレーザー光を直進させ、セルに、例えば
0.1μm〜0.3μmの粒子(粒径はレーザー光の波
長より小さく、かつ同一粒径粒子を用いる)を加えてい
く。実際は、Coulter社のLATEX MICR
OSPHRES 0.3μmをよくふり、マイクロピペ
ットで10μlずつ何回か加えることによりコヒーレン
ト拡散が生じるようになる。この状態では加えた粒径よ
り大きな粒子が干渉縞を生じる。
Embodiment 2 In the optical system of Embodiment 1, a method of utilizing coherent diffusion by fine particles without tilting the quartz cell will be described. That is, a laser beam is made to travel straight in a state where the quartz cell is set upright, and particles of, for example, 0.1 μm to 0.3 μm (particle diameter is smaller than the wavelength of the laser light and particles of the same diameter are used) are applied to the cell. I will add. Actually, Coulter's LATEX MICR
Shake OSPHRES 0.3 μm well and add 10 μl several times with a micropipette to allow coherent diffusion. In this state, particles larger than the added particle size cause interference fringes.

【実施例3】実施例1において、セルに、1μmのラテ
ック粒子を分散させた水(超純水)を入れ、セルの片面
に指をあてると、しばらくして激しい干渉縞の流れがス
クリーン上に観察された。これは指の温度が30℃近く
あり生じた温度勾配によって水が、したがって微粒子の
流れが生じ、もって干渉縞の移動が生じるためである。
もし、これを光散乱法で観測したとすれば光散乱ノイズ
が多少大きくなるに過ぎない。このように、本発明は温
度センサー、熱センサーに利用できる。本発明は、微粒
子の移動を動的信号として極めて高感度に検出できるた
め、微粒子もしくはそれを分散させた液体を黒色とすれ
ば微弱な赤外線の検出にも用いることができる。その場
合、赤外線を吸収する有機溶媒に無機コロイドを分散さ
せ、さらに冷却して溶媒を低温恒温にすればさらに高感
度が得られる。
Example 3 In Example 1, water (ultra-pure water) in which 1 μm latex particles were dispersed was put into the cell, and a finger was placed on one side of the cell. After a while, a strong flow of interference fringes was observed on the screen. Was observed. This is because the temperature of the finger is close to 30 ° C., and the resulting temperature gradient causes the flow of water, and hence the flow of fine particles, and thus the movement of interference fringes.
If this was observed by the light scattering method, the light scattering noise would only increase somewhat. Thus, the present invention can be used for a temperature sensor and a heat sensor. Since the present invention can detect the movement of the fine particles as a dynamic signal with extremely high sensitivity, if the fine particles or the liquid in which the fine particles are dispersed are made black, it can be used for detecting weak infrared light. In this case, higher sensitivity can be obtained by dispersing the inorganic colloid in an organic solvent that absorbs infrared rays and further cooling the solvent to a low temperature and constant temperature.

【実施例4】図5に示すように、吸収セルは4面透明の
ものを用いヘリウムネオンレーザーの光軸とは直角方向
から励起レーザー光を照射する。励起レーザは、KGW
レーザーを用いた。吸収セルに0.3μmのラテックス
粒子(Coulter社のLATEX MICROSP
HRES)を分散させた水を入れておく。KGW励起レ
ーザーをパルス点灯(1Hz)し、スクリーン上の干渉
縞を観察した。その結果、励起レーザーのパルスに同調
して干渉縞の大きなゆらぎが観測された。これは、ラテ
ックス粒子が1.1μmのレーザー光を吸収して熱運動
を行い、その結果、干渉縞が変動するためである。この
ように、本発明は光熱変換の信号を干渉縞変化とにとら
える新しい分光法となりうる。
Embodiment 4 As shown in FIG. 5, an absorption cell having four transparent surfaces is used, and excitation laser light is irradiated from a direction perpendicular to the optical axis of a helium neon laser. The pump laser is KGW
A laser was used. 0.3 μm latex particles (LATEX MICROSP from Coulter) are placed in the absorption cell.
HRES) is dispersed therein. The KGW excitation laser was pulsed (1 Hz), and interference fringes on the screen were observed. As a result, a large fluctuation of interference fringes was observed in synchronization with the excitation laser pulse. This is because the latex particles perform thermal motion by absorbing the laser beam of 1.1 μm, and as a result, interference fringes fluctuate. Thus, the present invention can be a new spectroscopic method that captures a signal of photothermal conversion as a change in interference fringes.

【図面の簡単な説明】[Brief description of the drawings]

【図1】コヒーレント発散光の写真 (1)単なる透過光(水を入れた石英セルを透過したレ
ーザー光) (2)セルに付着したゴミによるスペックル (3)コヒーレント発散光 (4)コヒーレント発散光とセルなかの微粒子による散
乱光との干渉縞
Fig. 1 Photograph of coherent divergent light (1) Simple transmitted light (laser light transmitted through a quartz cell filled with water) (2) Speckle due to dust attached to the cell (3) Coherent divergent light (4) Coherent divergence Interference fringes between light and particles scattered by cells

【図2】コヒーレント発散干渉縞の模式図FIG. 2 is a schematic diagram of coherent diverging interference fringes.

【図3】本発明の感度(0.1μmフィルターろ過水) (1)セル中の粒子による光散乱(散乱光による信号は
みられない) ラインの低周波変動は、レーザー又は検出系に起因する
もので光散乱とは無関係である。 (2)コヒーレント発散干渉法(干渉縞による明白な振
動がみられる)
FIG. 3 Sensitivity of the present invention (filtered water with a 0.1 μm filter) (1) Light scattering by particles in a cell (no signal due to scattered light is observed) Low frequency fluctuation of a line is caused by a laser or a detection system. And is independent of light scattering. (2) Coherent divergence interferometry (obvious vibration due to interference fringes)

【図4】実施例1の説明図FIG. 4 is an explanatory diagram of the first embodiment.

【図5】実施例4の説明図FIG. 5 is an explanatory diagram of a fourth embodiment.

─────────────────────────────────────────────────────
────────────────────────────────────────────────── ───

【手続補正書】[Procedure amendment]

【提出日】平成8年10月28日[Submission date] October 28, 1996

【手続補正1】[Procedure amendment 1]

【補正対象書類名】図面[Document name to be amended] Drawing

【補正対象項目名】全図[Correction target item name] All figures

【補正方法】変更[Correction method] Change

【補正内容】[Correction contents]

【図2】 FIG. 2

【図3】 FIG. 3

【図4】 FIG. 4

【図1】 FIG.

【図5】 FIG. 5

フロントページの続き (51)Int.Cl.6 識別記号 庁内整理番号 FI 技術表示箇所 G01N 21/49 G01N 21/49 Z Continued on the front page (51) Int.Cl. 6 Identification number Agency reference number FI Technical display location G01N 21/49 G01N 21/49 Z

Claims (7)

【特許請求の範囲】[Claims] 【請求項1】 透明体の屈折率を局所的(数十ミクロ
ン)に変化させ、そこにレーザー光を照射し、コヒーレ
ント発散光を得る方法。
1. A method of locally changing the refractive index of a transparent body (several tens of microns) and irradiating the transparent body with laser light to obtain coherent divergent light.
【請求項2】 請求項1記載の方法により得られた発散
光と、測定対象物からの同一波長レーザー光の二次光
(散乱光、反射光、拡散光、回折光等)とを干渉させ、
得られた干渉縞を測定する干渉法。
2. The divergent light obtained by the method according to claim 1 and the secondary light (scattered light, reflected light, diffused light, diffracted light, etc.) of the same wavelength laser light from the object to be measured. ,
An interference method for measuring the obtained interference fringes.
【請求項3】 光散乱粒子を入れた測定セルに温度傾斜
を生じさせ、もって測定セル内に光散乱粒子の流れを生
じさせ、請求項2に記載する干渉法を適用する光散乱測
定法。
3. A light scattering measurement method to which the interferometry according to claim 2 is applied, wherein a temperature gradient is caused in the measurement cell containing the light scattering particles, thereby causing a flow of the light scattering particles in the measurement cell.
【請求項4】 光軸通過面とは異なる測定セル面を熱吸
収体とし、請求項3記載の方法を適用する熱検出法。
4. A heat detection method in which a measurement cell surface different from the optical axis passage surface is used as a heat absorber, and the method according to claim 3 is applied.
【請求項5】 測定セルの溶媒又は光散乱粒子を熱吸収
体とし、請求項3記載の方法を適用する熱検出法。
5. A heat detection method using the method according to claim 3, wherein the solvent or the light scattering particles in the measurement cell is used as a heat absorber.
【請求項6】 請求項3において、照射レーザー光とは
別に、パルス励起レーザー光を光散乱粒子及び溶質を含
む測定セルに照射し、溶質の励起光吸収による温度傾斜
を生じさせ、温度傾斜と溶質濃度との比例関係を利用す
る溶質濃度測定法。
6. The method according to claim 3, wherein, apart from the irradiation laser light, a pulse excitation laser light is applied to the measurement cell containing the light scattering particles and the solute to generate a temperature gradient due to absorption of the excitation light of the solute. A solute concentration measurement method that uses a proportional relationship with solute concentration.
【請求項7】 溶媒及び溶質を励起レーザー光の透明体
とし、光散乱粒子を吸収体とする請求項6記載の粒子測
定法。
7. The particle measuring method according to claim 6, wherein the solvent and the solute are made of a transparent body of the excitation laser beam, and the light scattering particles are made of an absorber.
JP19686296A 1996-06-21 1996-06-21 Coherent divergence interferometry Expired - Fee Related JP4042068B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP19686296A JP4042068B2 (en) 1996-06-21 1996-06-21 Coherent divergence interferometry

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP19686296A JP4042068B2 (en) 1996-06-21 1996-06-21 Coherent divergence interferometry

Publications (2)

Publication Number Publication Date
JPH109811A true JPH109811A (en) 1998-01-16
JP4042068B2 JP4042068B2 (en) 2008-02-06

Family

ID=16364901

Family Applications (1)

Application Number Title Priority Date Filing Date
JP19686296A Expired - Fee Related JP4042068B2 (en) 1996-06-21 1996-06-21 Coherent divergence interferometry

Country Status (1)

Country Link
JP (1) JP4042068B2 (en)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2942873A1 (en) * 2009-03-06 2010-09-10 Commissariat Energie Atomique DEVICE FOR MEASURING THE FOCAL DISTANCE OF A THERMAL LENS
JP2013072765A (en) * 2011-09-28 2013-04-22 National Institute Of Advanced Industrial & Technology Solute molecule transport device and method
CN103983610A (en) * 2014-05-12 2014-08-13 复旦大学 Trace fluid refractive index measuring device and measuring method based on spectrum interference
WO2015132880A1 (en) * 2014-03-04 2015-09-11 パイオニア株式会社 Measurement device and measurement method
JP2018006387A (en) * 2016-06-27 2018-01-11 キヤノン株式会社 Discharge device, imprint device, detection method, determination method, and method of manufacturing article

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2942873A1 (en) * 2009-03-06 2010-09-10 Commissariat Energie Atomique DEVICE FOR MEASURING THE FOCAL DISTANCE OF A THERMAL LENS
WO2010100168A1 (en) * 2009-03-06 2010-09-10 Commissariat A L'energie Atomique Et Aux Energies Alternatives Method and device for measuring the focal distance of a thermal lens
CN102414553A (en) * 2009-03-06 2012-04-11 原子能与替代能源委员会 Method and device for measuring the focal distance of a thermal lens
JP2012519836A (en) * 2009-03-06 2012-08-30 コミッサリア ア レネルジー アトミーク エ オ ゼネルジ ザルタナテイヴ Method and device for measuring the focal length of a thermal lens
US8547542B2 (en) 2009-03-06 2013-10-01 Commissariat A L 'energie Atomique Et Aux Energies Alternatives Device for measuring the focal distance of a thermal lens
JP2013072765A (en) * 2011-09-28 2013-04-22 National Institute Of Advanced Industrial & Technology Solute molecule transport device and method
WO2015132880A1 (en) * 2014-03-04 2015-09-11 パイオニア株式会社 Measurement device and measurement method
JPWO2015132880A1 (en) * 2014-03-04 2017-03-30 パイオニア株式会社 Measuring apparatus and measuring method
CN103983610A (en) * 2014-05-12 2014-08-13 复旦大学 Trace fluid refractive index measuring device and measuring method based on spectrum interference
CN103983610B (en) * 2014-05-12 2016-09-28 复旦大学 Trace quantity liquid refractivity measurement apparatus based on spectral interference and measuring method
JP2018006387A (en) * 2016-06-27 2018-01-11 キヤノン株式会社 Discharge device, imprint device, detection method, determination method, and method of manufacturing article
US10814534B2 (en) 2016-06-27 2020-10-27 Canon Kabushiki Kaisha Discharge apparatus, imprint apparatus, method of detection, method of determination, and method for manufacturing article

Also Published As

Publication number Publication date
JP4042068B2 (en) 2008-02-06

Similar Documents

Publication Publication Date Title
CN103308142B (en) A kind of speed of ultrasonic travelling wave in liquid and method and device of frequency measured
US5589936A (en) Optical measuring apparatus for measuring physichemical properties
Toker Holographic Interferometry: A Mach–Zehnder Approach
Glatt et al. Moiré deflectometry—ray tracing interferometry
JP2023513479A (en) Apparatus and method for high performance wide-field infrared spectroscopy and imaging
Torres et al. Optical method for simultaneous high-resolution measurement of heat and fluid flow: The case of Rayleigh-Bénard convection
US4682897A (en) Light scattering measuring apparatus
JP4042068B2 (en) Coherent divergence interferometry
JPH0843292A (en) Detector for measuring luminous intensity of scattered lightwith thin film of colloid-state medium
Venerus et al. Measurement of thermal diffusivity in polymer melts using forced Rayleigh light scattering
CN109342364A (en) A kind of solution detection method and device based on golden film photo-thermal effect
Kuczyński et al. Interference method for the determination of refractive indices and birefringence of liquid crystals
CN202916182U (en) Material characteristic detecting device based on standing wave-induced transient grating effect
JP3261339B2 (en) Pore distribution measuring device
US11221293B2 (en) Two-dimensional second harmonic dispersion interferometer
JPH0215814B2 (en)
JPS598762B2 (en) How to use the information
JPH01147306A (en) Film thickness measuring instrument
Li et al. A method for monitoring mass concentration of black carbon particulate matter using photothermal interferometry
Holoubek Light Scattering Speckle Photography
Ploss et al. Anisotropic thermal diffusivity of thin polymer films: Determination with a laser scanning microscope
JPS61137048A (en) Apparatus for measuring scattering of light
SU1608507A1 (en) Method of measuring gradient of refraction index of transparent objects
Fleming et al. FY17 Report for the Design of a Benchtop PTR System
JPS61137044A (en) Apparatus for measuring light scattering

Legal Events

Date Code Title Description
A977 Report on retrieval

Free format text: JAPANESE INTERMEDIATE CODE: A971007

Effective date: 20050804

A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20060718

A521 Request for written amendment filed

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20060911

A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20061121

A521 Request for written amendment filed

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20070119

TRDD Decision of grant or rejection written
A01 Written decision to grant a patent or to grant a registration (utility model)

Free format text: JAPANESE INTERMEDIATE CODE: A01

Effective date: 20071009

A61 First payment of annual fees (during grant procedure)

Free format text: JAPANESE INTERMEDIATE CODE: A61

Effective date: 20071101

R150 Certificate of patent or registration of utility model

Free format text: JAPANESE INTERMEDIATE CODE: R150

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20101122

Year of fee payment: 3

LAPS Cancellation because of no payment of annual fees