Abstract

We performed high-resolution Fourier-transform infrared (FTIR) spectroscopy of a polymethyl methacrylate (PMMA) sphere of unknown size in the Mie scattering region. Apart from a slow, oscillatory structure (wiggles), which is due to an interference effect, the measured FTIR extinction spectrum exhibits a ripple structure, which is due to electromagnetic resonances. We fully characterize the underlying electromagnetic mode structure of the spectrum by assigning mode numbers to each of the ripples in the measured spectrum. We show that analyzing the ripple structure in the spectrum in the wavenumber region from about 3000  cm1 to 8000  cm1 allows us to determine both the unknown radius of the sphere and the PMMA index of refraction, which shows a strong frequency dependence in this infrared spectral region. While in this paper we focus on examining a PMMA sphere as an example, our method of determining the refractive index and its dispersion from infrared extinction spectra is generally applicable for the determination of the index of refraction of any transparent substance that can be shaped into micron-sized spheres.

© 2016 Optical Society of America

Full Article  |  PDF Article
OSA Recommended Articles
Determining the size and refractive index of microspheres using the mode assignments from Mie resonances

Thomas C. Preston and Jonathan P. Reid
J. Opt. Soc. Am. A 32(11) 2210-2217 (2015)

Mechanism of the Photoinduced Refractive Index Increase in Polymethyl Methacrylate

M. J. Bowden, E. A. Chandross, and I. P. Kaminow
Appl. Opt. 13(1) 112-117 (1974)

Retrieval of aerosol refractive index from extinction spectra with a damped harmonic-oscillator band model

Gareth E. Thomas, Stephen F. Bass, Roy G. Grainger, and Alyn Lambert
Appl. Opt. 44(7) 1332-1341 (2005)

References

You do not have subscription access to this journal. Citation lists with outbound citation links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Cited By

You do not have subscription access to this journal. Cited by links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Figures (5)

You do not have subscription access to this journal. Figure files are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Tables (1)

You do not have subscription access to this journal. Article tables are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Equations (32)

You do not have subscription access to this journal. Equations are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Metrics

You do not have subscription access to this journal. Article level metrics are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription