Qhov sib txawv tseem ceeb ntawm Fraunhofer thiab Fresnel diffraction yog qhov sib npaug ntawm Fraunhofer diffraction nrog rau kev ua qauv ntawm qhov sib txawv ntawm cov nthwv dej uas muaj cov qauv diffraction tshwm nyob rau ntawm qhov deb ntawm cov khoom sib txawv, whereas Fresnel diffraction equation suav nrog tib txoj kev qauv rau tus qauv diffraction tsim nyob ze ntawm qhov khoom.
Diffraction yog ib qho tshwm sim uas tuaj yeem piav qhia raws li kev tawg ntawm lub teeb nyob ib puag ncig ntawm ib qho khoom thaum lub teeb pom kev zoo yog ib feem cuam tshuam los ntawm cov khoom ntawd qhov twg peb tuaj yeem pom qhov tsaus ntuj thiab lub teeb ntawm ntug ntawm tus duab ntxoov ntxoo ntawm cov khoom ntawd.
Fraunhofer Diffraction yog dab tsi?
Fraunhofer diffraction yog ib qho kev sib npaug uas muaj txiaj ntsig zoo hauv kev ua qauv ntawm qhov sib txawv ntawm cov nthwv dej uas tus qauv diffraction tshwm nyob rau ntawm qhov deb ntawm cov khoom sib txawv. Ntxiv mus, peb tuaj yeem siv qhov sib npaug no los ua qauv qhov sib txawv ntawm nthwv dej thaum tus qauv diffraction tshwm ntawm lub dav hlau focal ntawm lub lens duab. Qhov kev sib npaug no tau muaj npe tom qab tus kws tshawb fawb Joseph Von Fraunhofer.
Peb tuaj yeem ua qauv ntawm qhov cuam tshuam ntawm qhov sib txawv siv Huygens-Fresnel txoj cai, qhov twg Huygens tau tshaj tawm tias cov ntsiab lus ntawm lub hauv ntej wavefront tuaj yeem ua raws li qhov chaw ntawm spherical Secondary wavelets, thiab peb tuaj yeem siv cov lej ntawm cov wavelet thib ob rau txiav txim siab daim ntawv ntawm nthwv dej uas tab tom mus tom ntej. Qhov sib ntxiv ntawm wavelets no suav nrog ntau nthwv dej ntawm ntau theem thiab amplitudes. E.g. Qhov sib ntxiv ntawm ob lub nthwv dej nrog qhov sib npaug ntawm qhov sib npaug (uas yog nyob rau theem) tuaj yeem ua rau muaj kev hloov pauv muaj ob npaug amplitude.
Yog tias peb yuav txiav txim siab qhov sib txawv uas tshwm sim thaum muaj qhov nrug ntawm qhov aperture thiab dav hlau ntawm kev soj ntsuam, txoj kev kho qhov muag qhov ntev ntawm qhov aperture thiab qhov taw qhia ntawm kev soj ntsuam yuav txawv tsawg dua qhov wavelength ntawm lub teeb. Yog li ntawd, txoj kev nthuav tawm rau lub wavelet tuaj yeem suav tias yog qhov sib npaug ntawm txhua qhov ntawm qhov aperture mus rau qhov kev soj ntsuam. Qhov tshwm sim no muaj npe nyob deb, thiab peb tuaj yeem siv qhov sib npaug ntawm Fraunhofer diffraction los ua qauv hom diffraction.
Fresnel Diffraction yog dab tsi?
Fresnel diffraction yog ib qho kev sib npaug uas peb tuaj yeem siv rau kev nthuav tawm ntawm nthwv dej hauv thaj chaw ze. Yog li ntawd, nws tseem hu ua ze-field diffraction. Nws yog ib qho approximation ntawm Kirchhoff-Fresnel diffraction. Peb tuaj yeem siv qhov sib npaug no los xam cov qauv diffraction uas yog tsim los ntawm cov nthwv dej uas dhau los ntawm qhov aperture lossis ib puag ncig ib puag ncig yog tias peb tab tom saib nws los ntawm qhov ze ze rau qhov khoom.
Qhov kev sib npaug no qhia txog Fresnel tus lej, F ntawm kev kho qhov muag. Yog tias tus lej no siab dua 1, peb tuaj yeem xav txog qhov sib txawv nthwv dej nyob hauv thaj chaw ze. Txawm li cas los xij, qhov siv tau ntawm qhov kwv yees no nyob ntawm lub kaum sab xis ntawm lub nthwv dej. Fresnel diffraction equation tau qhia los ntawm Francesco Maria Grimaldi (Ltalis) hauv 17th xyoo pua. Nws tau siv lub hauv paus ntsiab lus ntawm Huygens txhawm rau tshawb xyuas qhov hloov pauv thaum lub sijhawm sib txawv.
Qhov txawv ntawm Fraunhofer thiab Fresnel Diffraction yog dab tsi?
Fraunhofer diffraction yog ib qho kev sib npaug uas muaj txiaj ntsig zoo hauv kev ua qauv ntawm qhov sib txawv ntawm cov nthwv dej uas tus qauv diffraction tshwm nyob rau ntawm qhov deb ntawm cov khoom sib txawv. Fresnel diffraction yog ib qho kev sib npaug uas peb tuaj yeem siv rau kev nthuav tawm ntawm cov nthwv dej hauv thaj tsam ze. Qhov sib txawv tseem ceeb ntawm Fraunhofer thiab Fresnel diffraction yog qhov sib npaug ntawm Fraunhofer diffraction nrog cov qauv ntawm qhov sib txawv ntawm cov nthwv dej uas muaj cov qauv diffraction tshwm nyob rau ntawm qhov deb ntawm cov khoom sib txawv, qhov sib npaug ntawm Fresnel diffraction yog tib yam qauv qauv tsim nyob ze rau cov qauv diffraction. khoom.
Cov lus hauv qab no qhia txog qhov sib txawv ntawm Fraunhofer thiab Fresnel diffraction.
Summary – Fraunhofer vs Fresnel Diffraction
Qhov sib txawv tseem ceeb ntawm Fraunhofer thiab Fresnel diffraction yog qhov sib npaug ntawm Fraunhofer diffraction suav nrog kev ua qauv ntawm qhov sib txawv ntawm cov nthwv dej uas muaj cov qauv diffraction tshwm nyob rau ntawm qhov deb ntawm cov khoom sib txawv, whereas Fresnel diffraction equation koom nrog tib qauv qauv rau diffraction qauv tsim nyob ze ntawm qhov khoom.
