Thin Film Optics

1. Thin Film Optics • Physics of thin film optics • Important spectral features • BaCuSF data

2. Optics basics k wave vector n = index of refraction a = absorption coefficient k = extinction coefficient e = dielectric constant

3. Real sample with surfaces Bulk sample Absorption d

4. Thin Film on substrate r1 t1 r2 n1=n d t2 n2=s r3 t3 • polarization • angle

5. Surface reflection and transmission

6. R & T for real sample(no fringes) surface coeffs surface coeffs multiple bounces multiple bounces

7. R & T for real sample(w/ fringes)

8. Deduce Abs Coeff from R & T Transmission normalized to what it “should” have been

9. Thin Film Interference Fringesn=2.5,s=1.5, d=0.4µm m=2 m=1 Transmission Reflection

10. Thin Film Interference Fringesn=2.5, s=1.5, d=1µm m=7 m=6

11. Dispersion tightens up fringesn=2.6+, s=1.51, d=1µm

12. Absorption cuts transmissionn=2.6+, s=1.51, d=1µm, absorption (blue)

13. Index, absorption model (amorph Si)

14. Fringes vs angle

15. Effect of ignoring last surfacen=2.6+, s=1.51, d=1µm, absorption (blue)red=no substrate, black = w/ substrate

16. Analysis to find absorptionn =2.6+, s=1.51, d=1µmblue=abs, red = R+T, black=T/(1-R)

17. Determine absn dispersive, s=1.51, d=1µmblue=abs, black = T/(1-R), red=expt abs

18. Average transmission fringesn dispersive, s=1.51, d=1µm

19. Average reflection fringesn dispersive, s=1.51, d=1µm

21. Grating Spectrometer

22. BaCuSF Transmission

23. BaCuSF Gap analysis

24. BaCuSF Gap analysis

25. BaCuSF R, T Spectra

26. BaCuSF Index

27. BaCuSF Reflection (th vs expt)

28. BaCuSF Transmission (th vs expt)