## Scattering and Internal Fields of a Microsphere that Contains a Saturable Absorber: Finite-Difference Time-Domain Simulations

Applied Optics, Vol. 40, Issue 30, pp. 5487-5494 (2001)

http://dx.doi.org/10.1364/AO.40.005487

Acrobat PDF (997 KB)

### Abstract

Illumination intensities that are used to induce scattering and fluorescence in aerosols can be large enough to cause variations in the refractive index. Methods used to calculate the scattering from homogeneous particles may not be valid for these systems. We use the finite-difference time-domain method and an iterative technique to model scattering by microspheres that contain a saturable absorber. We illustrate this technique by calculating the scattering from spheres that contain tryptophan. We show the Mueller scattering matrices along with the internal intensity distributions for different incident intensities. The backscattering increases as the illumination intensity becomes large enough to saturate the absorption in regions of the sphere.

© 2001 Optical Society of America

**OCIS Codes**

(010.1100) Atmospheric and oceanic optics : Aerosol detection

(190.3970) Nonlinear optics : Microparticle nonlinear optics

(290.4020) Scattering : Mie theory

(290.5850) Scattering : Scattering, particles

**Citation**

Steven C. Hill, Gorden Videen, Wenbo Sun, and Qiang Fu, "Scattering and Internal Fields of a Microsphere that Contains a Saturable Absorber: Finite-Difference Time-Domain Simulations," Appl. Opt. **40**, 5487-5494 (2001)

http://www.opticsinfobase.org/ao/abstract.cfm?URI=ao-40-30-5487

Sort: Year | Journal | Reset

### References

- D. Q. Chowdhury, S. C. Hill, and M. M. Mazumder, “Absorptive bistability in a dielectric sphere,” Opt. Commun. 131, 343–346 (1996).
- J. Popp, M. H. Fields, and R. K. Chang, “Q switching by saturable absorption in microdroplets: elastic scattering and laser emission,” Opt. Lett. 22, 1296–1298 (1997).
- J. A. Lock and E. A. Hovenac, “Internal caustic structure of illuminated liquid droplets,” J. Opt. Soc. Am. A 8, 1541–1549 (1991).
- N. Velesco, T. Kaiser, and G. Schweiger, “Computation of the internal field of a large spherical particle by use of the geometrical-optics approximation,” Appl. Opt. 36, 8724–8727 (1997).
- K. S. Yee, “Numerical solution of initial boundary value problems involving Maxwell’s equations in isotropic media,” IEEE Trans. Antennas Propag. 14, 302–307 (1966).
- A. Taflove, Computational Electrodynamics, The Finite-Difference Time-Domain Method (Artech House, Boston, Mass., 1995).
- P. Yang and K. N. Liou, “Finite-difference time-domain method for light scattering by small ice crystals in three-dimensional space,” J. Opt. Soc. Am. A 13, 2072–2085 (1996).
- W. B. Sun, Q. Fu, and Z. Z. Chen, “Finite-difference time-domain solution of light scattering by dielectric particles with a perfectly matched layer absorbing boundary condition,” Appl. Opt. 38, 3141–3151 (1999).
- P. Yang, K. N. Liou, M. I. Mishchenko, and B.-C. Gao, “Efficient finite-difference time-domain scheme for light scattering by dielectric particles: application to aerosols,” Appl. Opt. 39, 3727–3737 (2000).
- W. B. Sun and Q. Fu, “Finite-difference time-domain solution of light scattering by dielectric particles with large complex refractive indices,” Appl. Opt. 39, 5569–5578 (2000).
- R. F. Harrington, Field Computation by Moment Methods (Macmillan, New York, 1968).
- B. T. Draine and P. J. Flatau, “Discrete-dipole approximation for scattering calculations,” J. Opt. Soc. Am. A 11, 1491–1499 (1994).
- R. M. Joseph and A. Taflove, “FDTD Maxwell’s equations models for nonlinear electrodynamics and optics,” IEEE Trans. Antennas Propag. 45, 364–374 (1997).
- R. W. Ziolkowski, “The incorporation of microscopic material models into the FDTD approach for ultrafast optical pulse simulations,” IEEE Trans. Antennas Propag. 45, 375–391 (1997).
- W. Forysiak, J. V. Moloney, and E. M. Wright, “Nonlinear focusing of femtosecond pulses as a result of self-reflection from a saturable absorber,” Opt. Lett. 22, 239–241 (1997).
- A. S. Nagra and R. A. York, “FDTD analysis of wave propagation in nonlinear absorbing and gain media,” IEEE Trans. Antennas Propag. 46, 334–340 (1998).
- R. G. Pinnick, S. C. Hill, P. Nachman, J. D. Pendleton, G. L. Fernandez, M. W. Mayo, and J. G. Bruno, “Fluorescence particle counter for detecting airborne bacteria and other biological particles,” Aerosol Sci. Technol. 23, 653–664 (1995).
- P. P. Hairston, J. Ho, and F. R. Quant, “Design of an instrument for real-time detection of bioaerosols using simultaneous measurement of particle aerodynamic size and intrinsic fluorescence,” J. Aerosol Sci. 28, 471–482 (1997).
- M. Seaver, J. D. Eversole, J. J. Hardgrove, W. K. Cary, and D. C. Roselle, “Size and fluorescence measurements for field detection of biological aerosols,” Aerosol Sci. Technol. 30, 174–185 (1999).
- Y. L. Pan, S. Holler, R. K. Chang, S. C. Hill, R. G. Pinnick, S. Niles, and J. R. Bottiger, “Single-shot fluorescence spectra of individual micrometer-sized bioaerosols illuminated by a 351- or 266-nm ultraviolet laser,” Opt. Lett. 24, 116–118 (1999).
- F. L. Reyes, T. H. Jeys, N. R. Newbury, C. A. Primmerman, G. S. Rowe, and A. Sanchez, “Bio-aerosol fluorescence sensor,” Field Analyt. Chem. Technol. 3, 240–248 (1999).
- J. D. Eversole, J. J. Hardgrove, W. K. Cary, D. P. Choulas, and M. Seaver, “Continuous rapid biological aerosol detection with the use of UV fluorescence: outdoor test results,” Field Analyt. Chem. Technol. 3, 249–259 (1999).
- P. H. Kaye, J. E. Barton, E. Hirst, and J. M. Clark, “Simultaneous light scattering and intrinsic fluorescence measurement for the classification of airborne particles,” Appl. Opt. 39, 3738–3745 (2000).
- S. C. Hill, R. G. Pinnick, S. Niles, Y. Pan, S. Holler, R. K. Chang, J. R. Bottiger, B. T. Chen, C.-S. Orr, and G. Feather, “Real-time measurement of fluorescence spectra from single airborne biological particles,” Field Analyt. Chem. Technol. 3, 221–239 (1999).
- S. Holler, Y. Pan, R. K. Chang, J. R. Bottiger, S. C. Hill, and D. B. Hillis, “Two-dimensional angular light scattering for the characterization of airborne microparticles,” Opt. Lett. 23, 1489–1491 (1998).
- G. Videen, W. Sun, Q. Fu, D. R. Secker, R. Greenaway, P. H. Kaye, E. Hirst, and D. Bartley, “Light scattering from deformed droplets and droplets with inclusion. II. Theoretical treatment,” Appl. Opt. 39, 5031–5039 (2000).
- D. R. Secker, R. Greenaway, P. H. Kaye, E. Hirst, D. Bartley, and G. Videen, “Light scattering from deformed droplets and droplets with inclusion. I. Experimental results,” Appl. Opt. 39, 5023–5030 (2000).
- S. Holler, J.-C. Auger, B. Stout, Y. Pan, J. Bottiger, R. Chang, and G. Videen, “Observations and calculations of light scattering from clusters of spheres,” Appl. Opt. 39, 6873–6887 (2000).
- W. G. Murrell, “Chemical composition of spores and spore structures,” in The Bacterial Spore A. Hurst, G. W. Gould, eds. (Academic, New York, 1969), Chap. 7, pp. 218–231, Table III, p. 221.
- W. Leupacher and A. Penzkofer, “Refractive index measurement of absorbing condensed media,” Appl. Opt. 23, 1554–1558 (1984).
- Our use of the term intensity (W/cm2) follows common usage in research in light scattering by particles. Unfortunately, it may be confusing to those used to the term irradiance (W/m2).
- From m2 = ε, where ε is the relative complex permittivity, and from γ = ς(Nupper − Nlower), where γ is the absorption per unit length for the intensity of a wave propagating in the medium. See, e.g., A. Yariv, Quantum Electronics, 3rd ed. (Wiley, New York, 1989), pp. 162–163, 203.
- J.-P. Berenger, “A perfectly matched layer for the absorption of electromagnetic waves,” J. Comput. Phys. 114, 185–200 (1994).
- C. F. Bohren and D. R. Huffman, Absorption and Scattering of Light by Small Particles (Wiley, New York, 1983), pp. 82–101.
- P. W. Barber and S. C. Hill, Light Scattering by Particles: Computational Methods (World Scientific, Singapore, 1990), pp. 205–210.
- Ref. 35, pp. 212, 214–215.
- S. C. Hill, V. Boutou, J. Yu, S. Ramstein, J.-P. Wolf, Y.-L. Pan, S. Holler, and R. K. Chang, “Enhanced backward-directed multi-photon-excited fluorescence from dielectric microcavities,” Phys. Rev. Lett. 85, 54–57 (2000).

## Cited By |
Alert me when this paper is cited |

OSA is able to provide readers links to articles that cite this paper by participating in CrossRef's Cited-By Linking service. CrossRef includes content from more than 3000 publishers and societies. In addition to listing OSA journal articles that cite this paper, citing articles from other participating publishers will also be listed.

« Previous Article | Next Article »

OSA is a member of CrossRef.