一、光譜儀是干什么用的

光譜儀又稱分(fen)光(guang)(guang)儀，廣泛為人知的(de)(de)為直讀光(guang)(guang)譜儀。以光(guang)(guang)電倍增管等光(guang)(guang)探測(ce)器(qi)測(ce)量譜線不同(tong)波長(chang)位置強度的(de)(de)裝置。它由一(yi)(yi)個(ge)入射狹縫，一(yi)(yi)個(ge)色(se)散系(xi)統(tong)，一(yi)(yi)個(ge)成像(xiang)系(xi)統(tong)和一(yi)(yi)個(ge)或多(duo)個(ge)出射狹縫組(zu)成。以色(se)散元件(jian)將輻射源的(de)(de)電磁輻射分(fen)離出所(suo)需要的(de)(de)波長(chang)或波長(chang)區域，并在(zai)選定的(de)(de)波長(chang)上（或掃描某一(yi)(yi)波段）進行強度測(ce)定。分(fen)為單(dan)色(se)儀和多(duo)色(se)儀兩種。

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二、光譜儀的原理

根據光(guang)譜學理論，所有物質的原子(zi)或(huo)分(fen)子(zi)受到(dao)激勵(li)時(shi)既能(neng)發射一定波(bo)(bo)長的電(dian)磁(ci)波(bo)(bo)，也(ye)能(neng)吸收(shou)這一波(bo)(bo)長的電(dian)磁(ci)波(bo)(bo)。當一束白光(guang)通(tong)過棱(leng)鏡或(huo)光(guang)柵時(shi)，就被分(fen)散(san)(san)成(cheng)一系(xi)列不(bu)同波(bo)(bo)長的色(se)帶(dai)——光(guang)譜，這就是色(se)散(san)(san)現象。

光譜儀器主(zhu)要由光源、單(dan)色器和(he)探(tan)測器組(zu)成。發(fa)射光譜儀器最常用的光源是使樣品激發(fa)出(chu)的電火花、交直流電弧、感(gan)應耦合等離子體和(he)激光等。吸收光譜儀器的光源主(zhu)要采用各種(zhong)紫外(wai)、可(ke)見或(huo)紅外(wai)光源或(huo)能發(fa)射某一元(yuan)素所特有譜線的空(kong)心陰(yin)極燈(deng)（由矩形脈沖(chong)供電）。已有70余種(zhong)元(yuan)素和(he)30多種(zhong)復合元(yuan)素的空(kong)心陰(yin)極燈(deng)，可(ke)在很短時間內變換元(yuan)素燈(deng)或(huo)調節(jie)燈(deng)光的強度。

單(dan)色器(qi)由分(fen)光(guang)(guang)(guang)(guang)(guang)(guang)元(yuan)件和狹縫(feng)組成，它的作用(yong)(yong)(yong)(yong)是將光(guang)(guang)(guang)(guang)(guang)(guang)波按波長分(fen)散開來，又稱分(fen)光(guang)(guang)(guang)(guang)(guang)(guang)器(qi)或單(dan)色儀，過去用(yong)(yong)(yong)(yong)棱鏡分(fen)光(guang)(guang)(guang)(guang)(guang)(guang)，新型儀器(qi)已(yi)大(da)多改用(yong)(yong)(yong)(yong)光(guang)(guang)(guang)(guang)(guang)(guang)柵(zha)，故(gu)光(guang)(guang)(guang)(guang)(guang)(guang)譜儀器(qi)又分(fen)為(wei)(wei)光(guang)(guang)(guang)(guang)(guang)(guang)柵(zha)光(guang)(guang)(guang)(guang)(guang)(guang)譜儀或棱鏡光(guang)(guang)(guang)(guang)(guang)(guang)譜儀。棱鏡光(guang)(guang)(guang)(guang)(guang)(guang)譜儀在紫外波段(duan)有較大(da)的色散率(lv)，常用(yong)(yong)(yong)(yong)于堿(jian)金(jin)屬、稀土(tu)元(yuan)素和礦(kuang)物分(fen)析。光(guang)(guang)(guang)(guang)(guang)(guang)柵(zha)按制造工藝可(ke)分(fen)為(wei)(wei)刻劃(hua)光(guang)(guang)(guang)(guang)(guang)(guang)柵(zha)和全(quan)息光(guang)(guang)(guang)(guang)(guang)(guang)柵(zha)，按工作表面幾(ji)何形(xing)狀可(ke)分(fen)為(wei)(wei)平(ping)面光(guang)(guang)(guang)(guang)(guang)(guang)柵(zha)和凹面光(guang)(guang)(guang)(guang)(guang)(guang)柵(zha)等(deng)。為(wei)(wei)了提高儀器(qi)的分(fen)辨本領和信噪比(bi)，可(ke)以采(cai)用(yong)(yong)(yong)(yong)更密的光(guang)(guang)(guang)(guang)(guang)(guang)柵(zha)刻線或用(yong)(yong)(yong)(yong)幾(ji)塊(kuai)光(guang)(guang)(guang)(guang)(guang)(guang)柵(zha)組合成單(dan)色器(qi)。

探測(ce)器的作(zuo)用(yong)(yong)(yong)(yong)是探測(ce)、顯示(shi)(shi)或(huo)記錄各譜(pu)(pu)線的位置(zhi)和強度。在攝譜(pu)(pu)儀中(zhong)采用(yong)(yong)(yong)(yong)感光(guang)板記錄，然后再(zai)用(yong)(yong)(yong)(yong)光(guang)譜(pu)(pu)投影儀和測(ce)微光(guang)度計測(ce)量。光(guang)量計和分光(guang)光(guang)度計都用(yong)(yong)(yong)(yong)光(guang)電(dian)(dian)器件（如光(guang)電(dian)(dian)倍增(zeng)管）或(huo)熱(re)電(dian)(dian)器件（如熱(re)電(dian)(dian)偶等）作(zuo)檢測(ce)元件，經光(guang)電(dian)(dian)變換放大后用(yong)(yong)(yong)(yong)檢流計顯示(shi)(shi)或(huo)用(yong)(yong)(yong)(yong)計算機(ji)處(chu)理(li)。

三、光譜儀的應用

光譜儀應用(yong)很廣(guang)，在農業(ye)、天(tian)文、汽車(che)、生物、化學、鍍(du)膜(mo)、色度計量(liang)、環(huan)境檢(jian)(jian)測(ce)(ce)(ce)、薄膜(mo)工業(ye)、食品、印刷、造紙(zhi)、拉曼光譜、半導體(ti)工業(ye)、成分檢(jian)(jian)測(ce)(ce)(ce)、顏(yan)色混合及(ji)匹配、生物醫學應用(yong)、熒光測(ce)(ce)(ce)量(liang)、寶(bao)石成分檢(jian)(jian)測(ce)(ce)(ce)、氧濃度傳(chuan)感器、真空室鍍(du)膜(mo)過(guo)程(cheng)監控、薄膜(mo)厚(hou)度測(ce)(ce)(ce)量(liang)、LED測(ce)(ce)(ce)量(liang)、發(fa)射光譜測(ce)(ce)(ce)量(liang)、紫外/可見(jian)吸收光譜測(ce)(ce)(ce)量(liang)、顏(yan)色測(ce)(ce)(ce)量(liang)等領域應用(yong)廣(guang)泛。