用MSV-5000系列显微分光光度计偏振测量单晶蓝宝石折射率

MSV-5000系列显微分光光度计适用于从紫外到近红外的宽波长范围内的透射和反射测量。高分辨率相机可实现直径小至10μm的样品区域。内置的Glan-Taylor偏振器允许通过测量双折射样品的反射光谱来获得折射率和消光系数等光学常数。Application NoteUV-0025 Estimation of the Refractive Index of a Monocrystalline Sapphire via Polarization2/4Application NoteMeasurement using the MSV-5000 Series Microscopic Spectrophotometer Estimation of the Refractive Index of a Monocrystalline Sapphire via Polarization Measurement using the MSV-5000 Series Microscopic Spectrophotomete r The MSV-5000 s e ri e s microscopic spectrophotom e t e r is for t r ansmi s sion and r e fl e ct i on mea s urements in a wide wavele n gth r a n ge fr om the u l t r aviolet t o n e ar i nf r ared. The h igh r e sol ut io n camera enables sample ar e as as smal l as 10um in d i ameter . T h e b ui lt -i n Glan-Taylor polarizer al l ows optical constants such as refractive i ndex a n d ext i nction coeff i c i e n t to be obtained by measuring the reflectance spect r um of birefringent samples. MSV-5200 In t h is appl i cation note， a 50 um monocrystal lin e sapphir e， wh i c h h as two typ e s of crystal ax e s， was mea s ur e d an d t h e d i spersion of the refract i ve ind e x was calcu l ated . U V-Vi s i b le/NIR Microsco p ic Spectrophotom e ter Keyword s MSV -5200 U V-Vi s /NIR m i c r o sc o pi c sp e c t r o ph o t o met e r ， VWML -791 Mult i-l a y er A n a l y s i s prog r a m， Mat e r i a l s Exper i mental Bandwidth 5nm Scan speed 200nm/min Response Slow Data interval 0.1nm Accumulation 3 Cassegrain objective 16x Incident Angle 23° IN/OUT aperture 50 um中 Polarizer Angle 0，90° Two baseli n es of an aluminum vapor-deposited mi rror was measured with the pol a rize r angle at 0 and 90° as a reference . T o determine the crystal li ne axis， the pola r izer angle was set to 0° and the wavelengt h 550 n m . The sam p le was then rotated to f i n d the ang l e whe r e the sample displayed maximum r eflectance. The c-axis was determined by this angle a n d the a-axis was taken orthogonal to it. T he sample r eflectance spectra were obtained with polarizer angles at 0and 90° for t he c- and a- axis， r espect i vely. The sample absolute reflectance spectrum was calculated by multiplying the obtained relative reflectance by the absolute r eflectance spectrum of the alum i num vapor-deposited mirror. The r e fract i ve i ndex can b e calculat e d by e i ther t h e UV-Vis K -K Conversion program or Multi -Layer Analysis program Using the UV-Vis K-K Conversion p rogram， the refractive index (n) is expressed by the specular re f lectance spectrum (R)and phase change (中 )： The phase cha n ge was calculated using the Kramers-Kronig co n version of the spec u la r r eflectance spectrum： and then the refractive in dex (n) was calcu l ated . Usin g t h e Multi -Laye r Analysis prog r am， t h e r e f l e ctance spectrum is e xpress e d by the r ef r ac t ive i nd e x of ai r and th e sampl e (n， n )， t he i ndic e nce angle (，)， and the refl e ct i on angle (8，)： By applying t h is equat i on， the wavelengt h d i spersion of the refractive index i s calcu l a t ed u sing the Multi-Layer Analysis program by fitting the calcu l ated ref l ectance spect r um to the measured . Resul t s The absolute r ef l ectance spectrum of monocrystalline sapphire is shown in Figure 1. The reflectance of the ordinary l ight (c-axis) i s approx i mate l y 0.15% h ighe r than that of the extraordinary light (a-axis). JASCO INC. Figu r e 1. A bsol u te re fle ctance sp e ctra o f t h e m o n ocrysta ll ine sa p ph i r e. Using the UV-Vis K-K Conversion a n d Multi-Layer Analysis program， the wave l ength dispersion of the refractive i n dex was obtained and shown i n Figure 2. Ta b les 1 and 2 i ll u st r ate t he results compared with literature values of t h e r ef r active i ndex of ordinary and extraordinary ligh t . The r efrac t ive i ndex was determined wi th in t wo deci m al places in an area seve r al tens of microns i n diamete r . Figure 2. Wav el ength disp er sio n o f t he re f r a cti v e in de x ca l c ula te d u si n g th e UV -V i s K -K C o n v er s i o n pro gra m (l eft )a n d Mul ti -La y e r A n a l y si s p rogram (r i g ht ). JASCO INC. 28600 Mary's Cour t ， E a s to n ， M D 21601US A UASGO Table 1. Comp a riso n of th e calcu l a t ed r e fr a c t i ve i nde x val ue s o f or d in ar y l igh t (c -a xi s ) u si n g the U V-V i s K -K C o n v e r s i o n p ro gr am w i th t h e liter atur e v al ue s. Literature value K-K Transform Multilayer Analysis Wavelength (nm) Refractive Index Refractive Index Error Refractive Index Error 632.8 1.776 1.770 0.0037 1.769 0.0036 589.3 1.768 1.770 0.0016 1.771 0.0028 546.1 1.771 1.772 0.0012 1.773 0.0018 532.0 1，772 1.771 -0.0005 1.773 0.0015 514.5 1.773 1.773 -0.0005 1.774 0.0011 488.0 1.775 1.775 -0.0005 1.776 0.0007 Table 2. Co mp ar i son o f t h e c al culated r efrac t i v e i nd e x v alues o f unordi n a r y li g h t (c -a x is ) u s i n g the U V -Vi s K -K C o nv er s i o n p r o gra m w i th t h e literat ur e va l ues. Wavelength (nm) Literature value K-K Transform Multilayer Analysis Refractive Index Refractive Index Error Refractive Index Error 632.8 1.758 1.757 -0.0005 1.758 -0.0003 589.3 1.760 1.758 -0.0015 1.759 -0.0011 546.1 1.763 1.761 -0.0017 1.761 -0.0020 532.0 1，764 1.761 -0.0030 1.761 -0.0022 514.5 1.765 1.762 -0.0032 1.762 -0.0026 488.0 1.767 1.764 -0.0028 1.764 -0.0030 JASCO INC. 28600 Mary's Cour t ， E a s to n ， M D 21601US A