Investigating the experimental limits of the Brewster’s angle method

Investigating the experimental limits of the Brewster’s angle method

We present the method, analysis, and experimental results of the Brewster’s angle method commonly used for determining the refractive indices of optical films. We show the significance of the intersection of reflectance curves, in that the necessity for substrate refractive index and film layer thickness knowledge are both eliminated. We present the conditions for the existence of the second intersection of reflectance curves and introduce a method for determining the refractive index of the substrate layer by using the angular information alone. Analytical results reveal impressive practical sensitivity and accuracy limits for the method, where the experimental results also support the theoretical analysis.

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  • Sümer C. Design and fabrication of a fiber-integrated mode-selective photopolymer grating coupler. PhD, İzmir Institute of Technology, ˙Izmir, Turkey, 2014.
  • [15] Surdutovich GI, Vitlina RZ, Baranauskas V. Anisotropic protective coating for Brewster angle windows. Appl Opt 1999; 38: 4172-4176.
  • Surdutovich GI, Vitlina RZ, Baranauskas V. Simple reflectometric method for measurement of weakly absorbing films. Thin Solid Films 1999; 355-356: 446-450.
  • Pawluczyk R. Modified Brewster angle technique for the measurement of the refractive index of a DCG layer. Appl Opt 1990; 29: 589-592.
  • Born M, Wolf E. Principles of Optics. 7th ed. New York, NY, USA: Cambridge Univ. Press, 1999.
  • Saleh BEA, Teich MC. Fundamentals of Photonics. New York, NY, USA: Wiley 2007.
  • Cordeiro CMB, Souza DR, Cescato L. Sistema automatizado para medi¸cao do indice de refra¸cao de substratos e filmes dielietricos. Revista de F´ısica Aplicada e Instrumenta¸c˜ao 1999; 14: 72-78 (in Portuguese).
  • Dana KJ, Livescu G, Makonahalli R. Transparent watermarking using bidirectional imaging. In: IEEE Computer Society Conference on Computer Vision and Pattern Recognition, 20–25 June 2009; Miami, FL, USA. New York,NY, USA: IEEE. pp. 31-38.
  • Wu QH, Hodgkinson I. Precision of Brewster-angle methods for optical thin films. J Opt Soc Am A 1993; 10:2072-2075.
  • Abeles F. VI Methods for determining optical parameters of thin films. Prog Opt 1963; 2: 249-288.
  • Schutzmann S, Casalboni M, Matteis FD, Prosposito P. Refractive index measurements of thin films using both Brewster and m-line technique: a combined experimental setup. J Non-Cryst Solids 2005; 351: 1814-1818.
  • Luna-Moreno D, De la Rosa-Cruz E. Cuevas FJ, Regalado LE, Salas P, Rodriguez R, Casta˜no VM. Refractive index measurement of pure and Er3+ -doped ZrO2–SiO2 sol–gel film by using the Brewster angle technique. Opt Mater 2002; 19: 275-281.
  • Holmes DC, Johnson RP. Small-spot thin-film thickness-measurements with Brewster’s angle reflectometer. In: Microelectronic Manufacturing; 19 September 1994; Austin, TX, USA. Bellingham, WA, USA: SPIE. pp. 176-182.
  • Dinleyici MS, Sümer C. Characterization and estimation of refractive index profile of laser-written photopolymer optical waveguides. Opt Commun 2011; 284: 5067-5071.
  • Tien PK, Ulrich R. Theory of prism-film coupler and thin-film light guides. J Opt Soc Am 1970; 60: 1325-1337.
  • Fujiwara H. Spectroscopic Ellipsometry: Principles and Applications. New York, NY, USA: Wiley, 2007.