Keywords: VPH Khoom-theem holographic grating, Transmittance spectrophotometer, Reflectance spectrometer, Czerny-Turner Optical txoj kev.
1. Txheej txheem cej luam
Lub fiber optic spectrometer tuaj yeem raug cais raws li kev xav thiab kev sib kis, raws li hom diffraction grating.Ib qho diffraction grating yog ib qho khoom siv kho qhov muag, uas muaj ntau tus qauv sib npaug sib npaug ntawm qhov chaw lossis sab hauv.Nws yog ib qho tseem ceeb ntawm fiber ntau optic spectrometer.Thaum lub teeb cuam tshuam nrog cov grating no, tawg mus rau hauv cov ces kaum sib txawv txiav txim siab los ntawm qhov sib txawv wavelengths los ntawm qhov tshwm sim hu ua lub teeb diffraction.
Saum toj no: Kev ntxub ntxaug reflectance spectrometer (sab laug) thiab transmittance spectrometer (txoj cai)
Diffraction gratings feem ntau muab faib ua ob hom: kev xav thiab kev sib kis gratings.Reflection gratings tuaj yeem muab faib ntxiv rau hauv dav hlau kev xav gratings thiab concave gratings, thaum kis tau tus mob gratings tuaj yeem muab faib ua groove-type kis gratings thiab ntim theem holographic (VPH) kis gratings.Kab lus no feem ntau qhia txog lub dav hlau blaze grating-hom reflectance spectrometer thiab VPH grating-type transmittance spectrometer.
Saum toj no: Reflection grating (sab laug) thiab Transmission grating (sab xis).
Vim li cas feem ntau spectrometers tam sim no xaiv grating dispersion es tsis txhob prism?Nws yog feem ntau txiav txim siab los ntawm grating cov ntsiab lus spectral.Tus naj npawb ntawm kab ib millimeter ntawm lub grating (kab ceev, chav tsev: kab / hli) txiav txim siab lub grating lub spectral peev xwm.Ib txoj kab ntau dua grating ua rau muaj kev cuam tshuam ntau dua ntawm lub teeb ntawm qhov sib txawv wavelengths tom qab dhau los ntawm grating, ua rau kev daws teeb meem ntau dua.Feem ntau, muaj thiab grating groove densities muaj xws li 75, 150, 300, 600, 900, 1200, 1800, 2400, 3600, thiab lwm yam, ua tau raws li qhov yuav tsum tau muaj rau ntau yam spectral ntau thiab kev daws teeb meem.Thaum lub sij hawm, prism spectroscopy yog txwv los ntawm dispersion ntawm iav cov ntaub ntawv, qhov twg cov khoom dispersive ntawm iav txiav txim lub spectroscopic muaj peev xwm ntawm lub prism.Txij li thaum dispersive cov khoom ntawm iav cov ntaub ntawv raug txwv, nws yog ib qho nyuaj rau flexibly ua tau raws li qhov yuav tsum tau ntawm ntau yam spectral daim ntaub ntawv.Yog li ntawd, nws tsis tshua muaj siv nyob rau hauv kev lag luam me me fiber ntau optic spectrometers.
Nqe lus piav qhia: Spectral teebmeem ntawm qhov sib txawv grating groove ntom nyob rau hauv daim duab saum toj no.
Daim duab qhia tau hais tias dispersion spectrometry ntawm lub teeb dawb los ntawm iav thiab diffraction spectrometry los ntawm grating.
Kev loj hlob keeb kwm ntawm gratings, pib nrog cov classic "Young's ob-slit xyaum ua tej yam": Nyob rau hauv 1801, tus British physicist Thomas Young nrhiav tau qhov cuam tshuam ntawm lub teeb uas siv ib tug ob-slit xyaum ua tej yam.Monochromatic lub teeb dhau los ntawm ob qhov slits nthuav tawm alternating ci thiab tsaus fringes.Qhov kev sim ob-slit thawj zaug tau lees paub tias lub teeb pom cov yam ntxwv zoo ib yam li dej nthwv dej (nthwv dej ntawm lub teeb), ua rau muaj kev xav hauv zej zog physics.Tom qab ntawd, ntau tus kws kho mob tau ua ntau qhov kev cuam tshuam cuam tshuam thiab pom qhov tshwm sim ntawm qhov pom ntawm lub teeb los ntawm gratings.Tom qab ntawd, Fabkis physicist Fresnel tau tsim txoj kev xav ntawm grating diffraction los ntawm kev sib txuas cov kev ua lej uas tau tsim los ntawm tus kws tshawb fawb German Huygens, kos rau cov txiaj ntsig no.
Daim duab qhia Young qhov kev cuam tshuam ob npaug ntawm sab laug, nrog kev sib hloov kaj thiab tsaus nti fringes.Multi-slit diffraction (txoj cai), kev faib cov xim xim ntawm ntau qhov kev txiav txim.
2.Reflective Spectrometer
Cov spectrometers feem ntau yog siv txoj hauv kev kho qhov muag uas muaj lub dav hlau diffraction grating thiab concave tsom iav, hu ua Czerny-Turner optical path.Nws feem ntau muaj cov hlais, lub dav hlau blaze grating, ob daim iav concave, thiab lub ntes.Qhov kev teeb tsa no yog tus cwj pwm los ntawm kev daws teeb meem siab, tsis tshua muaj teeb pom kev zoo, thiab siab optical throughput.Tom qab lub teeb teeb pom kev zoo nkag los ntawm qhov nqaim nqaim, nws yog thawj zaug sib tsoo rau hauv lub teeb sib luag los ntawm lub concave reflector, uas tom qab ntawd ntaus cov phiaj xwm diffractive grating qhov twg cov wavelengths muaj qhov sib txawv ntawm cov ces kaum sib txawv.Thaum kawg, lub concave reflector tsom lub teeb pom kev mus rau lub photodetector thiab cov teeb liab ntawm qhov sib txawv wavelengths raug kaw los ntawm pixels ntawm ntau txoj haujlwm ntawm photodiode nti, thaum kawg tsim ib spectrum.Feem ntau, lub reflection spectrometer kuj suav nrog qee qhov thib ob-txiav txim siab diffraction-suppressing filters thiab kem lo ntsiab muag los txhim kho qhov zoo ntawm cov zis spectra.
Daim duab qhia tau hais tias tus ntoo khaub lig-hom CT optical txoj kev grating spectrometer.
Nws yuav tsum tau hais tias Czerny thiab Turner tsis yog cov neeg tsim khoom ntawm qhov kho qhov muag tab sis tau ua kev nco txog rau lawv txoj kev koom tes zoo rau kev kho qhov muag - Austrian astronomer Adalbert Czerny thiab German kws tshawb fawb Rudolf W. Turner.
Txoj kev kho qhov muag Czerny-Turner feem ntau tuaj yeem faib ua ob hom: hla thiab nthuav tawm (M-hom).Txoj kev hla kev kho qhov muag / M-hom optical txoj kev yog qhov sib txuam ntau dua.Ntawm no, sab laug-txoj cai symmetrical faib ntawm ob daim iav concave txheeb ze rau lub dav hlau grating, nthuav qhia kev sib nrig sib pab ntawm off-axis aberrations, ua rau muaj kev daws teeb meem ntau dua.SpectraCheck® SR75C fiber optic spectrometer ntiav M-type optical txoj kev, ua tiav qhov kev daws teeb meem siab txog li 0.15nm hauv ultraviolet ntau ntawm 180-340 nm.
Saum toj no: Cross-type optical path/expanded-type (M-type) optical path.
Tsis tas li ntawd, sib nrug los ntawm cov pav ca blaze gratings, kuj tseem muaj concave blaze grating.Lub concave blaze grating tuaj yeem nkag siab tias yog kev sib xyaw ntawm daim iav concave thiab grating.Yog li ntawd, lub concave blaze grating spectrometer tsuas muaj ib tug slit, ib tug concave blaze grating, thiab ib tug ntes, ua rau muaj kev ruaj ntseg.Txawm li cas los xij, concave blaze grating teeb tsa qhov yuav tsum tau ua ntawm ob qho tib si kev taw qhia thiab kev ncua deb ntawm qhov teeb meem-diffracted teeb, txwv cov kev xaiv muaj.
Tom ntej: Concave grating spectrometer
Post lub sij hawm: Dec-26-2023