Abstract

We demonstrate a tunable on chip polymer waveguide micro ring resonator (MRR) device. The transmission spectrum and extinction ratio are controlled by electrowetting on dielectric (EWOD), via the application of voltage to a droplet. As a result the droplet covers a portion of the MRR waveguide and changes its effective refractive index. This method can be used for efficiently tuning a variety of on chip optical devices, as it offers high index contrast, electrical control and low power consumption.

© 2009 Optical Society of America

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  1. U. Levy and R. Shamai, "Tunable optofluidic devices," Microfluid Nanofluid 4, 97-105 (2007).
    [CrossRef]
  2. N. Chronis, G. L. Liu, K.H. Jeong, and L. P. Lee "Tunable liquid-filled microlens array integrated with microfluidic network," Opt. Express 11, 2370-2378 (2003).
    [CrossRef] [PubMed]
  3. L. Pang, U. Levy, K. Campbell, A. Groisman, and Y. Fainman, "A set of two orthogonal adaptive cylindrical lenses in a monolith elastomer device," Opt. Express 13, 9003-9013 (2005).
    [CrossRef] [PubMed]
  4. K. Campbell, U. Levy, Y. Fainman, and A. Groisman, "Pressure-driven devices with lithographically fabricated composite epoxy-elastomer membranes," Appl. Phys. Lett. 89, 154105-154107 (2006).
    [CrossRef]
  5. K. Campbell, A. Groisman, U. Levy, L. Pang, S. Mookherjea, D. Psaltis, and Y. Fainman, "A microfluidic 2x2 optical switch," Appl. Phys. Lett. 85, 6119-6121 (2004).
    [CrossRef]
  6. U. Levy, K. Campbell, A. Groisman, S. Mookherjea, and Y. Fainman, "On-chip microfluidic tuning of an optical microring resonator," Appl. Phys. Lett. 88, 111107-111109 (2006).
    [CrossRef]
  7. J. C. Galas, J. Torres, M. Belotti, Q. Kou, and Y. Chen, "Microfluidic tunable dye laser with integrated mixer and ring resonator," Appl. Phys. Lett. 86, 264101-264103 (2005).
    [CrossRef]
  8. Z. Li, Z. Zhang, A. Scherer, and D. Psaltis, "Mechanically tunable optofluidic distributed feedback dye laser," Opt. Express 14, 10494-10499 (2006).
    [CrossRef] [PubMed]
  9. M. Gersborg-Hansen and A. Kristensen, "Tunability of optofluidic distributed feedback dye lasers," Opt. Express 15, 137-142 (2007).
    [CrossRef] [PubMed]
  10. D. Erickson, T. Rockwood, T. Emery, A. Scherer, and D. Psaltis, "Nanofluidic tuning of photonic crystal circuits," Opt. Lett. 31, 59-61 (2006).
    [CrossRef] [PubMed]
  11. D. B. Wolfe, R. S. Conroy, P. Garstecki, B. T. Mayers, M. A, Fischbach, K. E. Paul, M. Prentiss, and G. M. Whitesides, "Dynamic control of liquid-core/liquid-cladding optical waveguides," PNAS 101, 12434-12438 (2004).
    [CrossRef] [PubMed]
  12. F.  Mugele and J-C  Baret, "Electrowetting: from basics to applications," J. Phys. Condens. Matter  17, R705-R774 (2005).
    [CrossRef]
  13. B. Berge and J. Peseux, "Variable focal lens controlled by an external voltage: an application of electrowetting," Eur. Phys. J. E 3, 159-163 (2000).
    [CrossRef]
  14. S. Kuiper and B. H. W. Hendriks, "Variable-focus liquid lens for miniature cameras," Appl. Phys. Lett. 85, 1128-1130 (2004).
    [CrossRef]
  15. R. A. Hayes and B. J. Feenstra, "Video-speed electronic paper based on electrowetting," Nature 425, 383-385 (2003).
    [CrossRef] [PubMed]
  16. N. R. Smith, D. C. Abeysinghe, J. W. Haus, and J. Heikenfeld, "Agile wide-angle beam steering with electrowetting microprisms," Opt. Express 14, 6557-6563 (2006).
    [CrossRef] [PubMed]
  17. P. Mach, T. Krupenkin, S. Yang, and J. A. Rogers, "Dynamic tuning of optical waveguides with electrowetting pumps and recirculating fluid channels," Appl. Phys. Lett. 81, 202-204 (2002).
    [CrossRef]
  18. S. Berry, J. Kedzierski, and B. Abedian, "Low voltage electrowetting using thin fluoroploymer films," J. Colloid Interface Sci. 303, 517-524 (2006).
    [CrossRef] [PubMed]
  19. K.W. Oh, A. Han, and S. Bhansali, "A low-temperature bonding technique using spin-on fluorocarbon polymers to assemble Microsystems," J. Micromech. Microeng. 12, 187-191 (2002).
    [CrossRef]

2007

2006

S. Berry, J. Kedzierski, and B. Abedian, "Low voltage electrowetting using thin fluoroploymer films," J. Colloid Interface Sci. 303, 517-524 (2006).
[CrossRef] [PubMed]

D. Erickson, T. Rockwood, T. Emery, A. Scherer, and D. Psaltis, "Nanofluidic tuning of photonic crystal circuits," Opt. Lett. 31, 59-61 (2006).
[CrossRef] [PubMed]

N. R. Smith, D. C. Abeysinghe, J. W. Haus, and J. Heikenfeld, "Agile wide-angle beam steering with electrowetting microprisms," Opt. Express 14, 6557-6563 (2006).
[CrossRef] [PubMed]

Z. Li, Z. Zhang, A. Scherer, and D. Psaltis, "Mechanically tunable optofluidic distributed feedback dye laser," Opt. Express 14, 10494-10499 (2006).
[CrossRef] [PubMed]

K. Campbell, U. Levy, Y. Fainman, and A. Groisman, "Pressure-driven devices with lithographically fabricated composite epoxy-elastomer membranes," Appl. Phys. Lett. 89, 154105-154107 (2006).
[CrossRef]

U. Levy, K. Campbell, A. Groisman, S. Mookherjea, and Y. Fainman, "On-chip microfluidic tuning of an optical microring resonator," Appl. Phys. Lett. 88, 111107-111109 (2006).
[CrossRef]

2005

J. C. Galas, J. Torres, M. Belotti, Q. Kou, and Y. Chen, "Microfluidic tunable dye laser with integrated mixer and ring resonator," Appl. Phys. Lett. 86, 264101-264103 (2005).
[CrossRef]

F.  Mugele and J-C  Baret, "Electrowetting: from basics to applications," J. Phys. Condens. Matter  17, R705-R774 (2005).
[CrossRef]

L. Pang, U. Levy, K. Campbell, A. Groisman, and Y. Fainman, "A set of two orthogonal adaptive cylindrical lenses in a monolith elastomer device," Opt. Express 13, 9003-9013 (2005).
[CrossRef] [PubMed]

2004

S. Kuiper and B. H. W. Hendriks, "Variable-focus liquid lens for miniature cameras," Appl. Phys. Lett. 85, 1128-1130 (2004).
[CrossRef]

D. B. Wolfe, R. S. Conroy, P. Garstecki, B. T. Mayers, M. A, Fischbach, K. E. Paul, M. Prentiss, and G. M. Whitesides, "Dynamic control of liquid-core/liquid-cladding optical waveguides," PNAS 101, 12434-12438 (2004).
[CrossRef] [PubMed]

K. Campbell, A. Groisman, U. Levy, L. Pang, S. Mookherjea, D. Psaltis, and Y. Fainman, "A microfluidic 2x2 optical switch," Appl. Phys. Lett. 85, 6119-6121 (2004).
[CrossRef]

2003

2002

K.W. Oh, A. Han, and S. Bhansali, "A low-temperature bonding technique using spin-on fluorocarbon polymers to assemble Microsystems," J. Micromech. Microeng. 12, 187-191 (2002).
[CrossRef]

P. Mach, T. Krupenkin, S. Yang, and J. A. Rogers, "Dynamic tuning of optical waveguides with electrowetting pumps and recirculating fluid channels," Appl. Phys. Lett. 81, 202-204 (2002).
[CrossRef]

2000

B. Berge and J. Peseux, "Variable focal lens controlled by an external voltage: an application of electrowetting," Eur. Phys. J. E 3, 159-163 (2000).
[CrossRef]

Abedian, B.

S. Berry, J. Kedzierski, and B. Abedian, "Low voltage electrowetting using thin fluoroploymer films," J. Colloid Interface Sci. 303, 517-524 (2006).
[CrossRef] [PubMed]

Abeysinghe, D. C.

Baret, J-C

F.  Mugele and J-C  Baret, "Electrowetting: from basics to applications," J. Phys. Condens. Matter  17, R705-R774 (2005).
[CrossRef]

Belotti, M.

J. C. Galas, J. Torres, M. Belotti, Q. Kou, and Y. Chen, "Microfluidic tunable dye laser with integrated mixer and ring resonator," Appl. Phys. Lett. 86, 264101-264103 (2005).
[CrossRef]

Berge, B.

B. Berge and J. Peseux, "Variable focal lens controlled by an external voltage: an application of electrowetting," Eur. Phys. J. E 3, 159-163 (2000).
[CrossRef]

Berry, S.

S. Berry, J. Kedzierski, and B. Abedian, "Low voltage electrowetting using thin fluoroploymer films," J. Colloid Interface Sci. 303, 517-524 (2006).
[CrossRef] [PubMed]

Bhansali, S.

K.W. Oh, A. Han, and S. Bhansali, "A low-temperature bonding technique using spin-on fluorocarbon polymers to assemble Microsystems," J. Micromech. Microeng. 12, 187-191 (2002).
[CrossRef]

Campbell, K.

U. Levy, K. Campbell, A. Groisman, S. Mookherjea, and Y. Fainman, "On-chip microfluidic tuning of an optical microring resonator," Appl. Phys. Lett. 88, 111107-111109 (2006).
[CrossRef]

K. Campbell, U. Levy, Y. Fainman, and A. Groisman, "Pressure-driven devices with lithographically fabricated composite epoxy-elastomer membranes," Appl. Phys. Lett. 89, 154105-154107 (2006).
[CrossRef]

L. Pang, U. Levy, K. Campbell, A. Groisman, and Y. Fainman, "A set of two orthogonal adaptive cylindrical lenses in a monolith elastomer device," Opt. Express 13, 9003-9013 (2005).
[CrossRef] [PubMed]

K. Campbell, A. Groisman, U. Levy, L. Pang, S. Mookherjea, D. Psaltis, and Y. Fainman, "A microfluidic 2x2 optical switch," Appl. Phys. Lett. 85, 6119-6121 (2004).
[CrossRef]

Chen, Y.

J. C. Galas, J. Torres, M. Belotti, Q. Kou, and Y. Chen, "Microfluidic tunable dye laser with integrated mixer and ring resonator," Appl. Phys. Lett. 86, 264101-264103 (2005).
[CrossRef]

Chronis, N.

Conroy, R. S.

D. B. Wolfe, R. S. Conroy, P. Garstecki, B. T. Mayers, M. A, Fischbach, K. E. Paul, M. Prentiss, and G. M. Whitesides, "Dynamic control of liquid-core/liquid-cladding optical waveguides," PNAS 101, 12434-12438 (2004).
[CrossRef] [PubMed]

Emery, T.

Erickson, D.

Fainman, Y.

U. Levy, K. Campbell, A. Groisman, S. Mookherjea, and Y. Fainman, "On-chip microfluidic tuning of an optical microring resonator," Appl. Phys. Lett. 88, 111107-111109 (2006).
[CrossRef]

K. Campbell, U. Levy, Y. Fainman, and A. Groisman, "Pressure-driven devices with lithographically fabricated composite epoxy-elastomer membranes," Appl. Phys. Lett. 89, 154105-154107 (2006).
[CrossRef]

L. Pang, U. Levy, K. Campbell, A. Groisman, and Y. Fainman, "A set of two orthogonal adaptive cylindrical lenses in a monolith elastomer device," Opt. Express 13, 9003-9013 (2005).
[CrossRef] [PubMed]

K. Campbell, A. Groisman, U. Levy, L. Pang, S. Mookherjea, D. Psaltis, and Y. Fainman, "A microfluidic 2x2 optical switch," Appl. Phys. Lett. 85, 6119-6121 (2004).
[CrossRef]

Feenstra, B. J.

R. A. Hayes and B. J. Feenstra, "Video-speed electronic paper based on electrowetting," Nature 425, 383-385 (2003).
[CrossRef] [PubMed]

Galas, J. C.

J. C. Galas, J. Torres, M. Belotti, Q. Kou, and Y. Chen, "Microfluidic tunable dye laser with integrated mixer and ring resonator," Appl. Phys. Lett. 86, 264101-264103 (2005).
[CrossRef]

Garstecki, P.

D. B. Wolfe, R. S. Conroy, P. Garstecki, B. T. Mayers, M. A, Fischbach, K. E. Paul, M. Prentiss, and G. M. Whitesides, "Dynamic control of liquid-core/liquid-cladding optical waveguides," PNAS 101, 12434-12438 (2004).
[CrossRef] [PubMed]

Gersborg-Hansen, M.

Groisman, A.

U. Levy, K. Campbell, A. Groisman, S. Mookherjea, and Y. Fainman, "On-chip microfluidic tuning of an optical microring resonator," Appl. Phys. Lett. 88, 111107-111109 (2006).
[CrossRef]

K. Campbell, U. Levy, Y. Fainman, and A. Groisman, "Pressure-driven devices with lithographically fabricated composite epoxy-elastomer membranes," Appl. Phys. Lett. 89, 154105-154107 (2006).
[CrossRef]

L. Pang, U. Levy, K. Campbell, A. Groisman, and Y. Fainman, "A set of two orthogonal adaptive cylindrical lenses in a monolith elastomer device," Opt. Express 13, 9003-9013 (2005).
[CrossRef] [PubMed]

K. Campbell, A. Groisman, U. Levy, L. Pang, S. Mookherjea, D. Psaltis, and Y. Fainman, "A microfluidic 2x2 optical switch," Appl. Phys. Lett. 85, 6119-6121 (2004).
[CrossRef]

Han, A.

K.W. Oh, A. Han, and S. Bhansali, "A low-temperature bonding technique using spin-on fluorocarbon polymers to assemble Microsystems," J. Micromech. Microeng. 12, 187-191 (2002).
[CrossRef]

Haus, J. W.

Hayes, R. A.

R. A. Hayes and B. J. Feenstra, "Video-speed electronic paper based on electrowetting," Nature 425, 383-385 (2003).
[CrossRef] [PubMed]

Heikenfeld, J.

Hendriks, B. H. W.

S. Kuiper and B. H. W. Hendriks, "Variable-focus liquid lens for miniature cameras," Appl. Phys. Lett. 85, 1128-1130 (2004).
[CrossRef]

Jeong, K.H.

Kedzierski, J.

S. Berry, J. Kedzierski, and B. Abedian, "Low voltage electrowetting using thin fluoroploymer films," J. Colloid Interface Sci. 303, 517-524 (2006).
[CrossRef] [PubMed]

Kou, Q.

J. C. Galas, J. Torres, M. Belotti, Q. Kou, and Y. Chen, "Microfluidic tunable dye laser with integrated mixer and ring resonator," Appl. Phys. Lett. 86, 264101-264103 (2005).
[CrossRef]

Kristensen, A.

Krupenkin, T.

P. Mach, T. Krupenkin, S. Yang, and J. A. Rogers, "Dynamic tuning of optical waveguides with electrowetting pumps and recirculating fluid channels," Appl. Phys. Lett. 81, 202-204 (2002).
[CrossRef]

Kuiper, S.

S. Kuiper and B. H. W. Hendriks, "Variable-focus liquid lens for miniature cameras," Appl. Phys. Lett. 85, 1128-1130 (2004).
[CrossRef]

Lee, L. P.

Levy, U.

U. Levy and R. Shamai, "Tunable optofluidic devices," Microfluid Nanofluid 4, 97-105 (2007).
[CrossRef]

K. Campbell, U. Levy, Y. Fainman, and A. Groisman, "Pressure-driven devices with lithographically fabricated composite epoxy-elastomer membranes," Appl. Phys. Lett. 89, 154105-154107 (2006).
[CrossRef]

U. Levy, K. Campbell, A. Groisman, S. Mookherjea, and Y. Fainman, "On-chip microfluidic tuning of an optical microring resonator," Appl. Phys. Lett. 88, 111107-111109 (2006).
[CrossRef]

L. Pang, U. Levy, K. Campbell, A. Groisman, and Y. Fainman, "A set of two orthogonal adaptive cylindrical lenses in a monolith elastomer device," Opt. Express 13, 9003-9013 (2005).
[CrossRef] [PubMed]

K. Campbell, A. Groisman, U. Levy, L. Pang, S. Mookherjea, D. Psaltis, and Y. Fainman, "A microfluidic 2x2 optical switch," Appl. Phys. Lett. 85, 6119-6121 (2004).
[CrossRef]

Li, Z.

Liu, G. L.

Mach, P.

P. Mach, T. Krupenkin, S. Yang, and J. A. Rogers, "Dynamic tuning of optical waveguides with electrowetting pumps and recirculating fluid channels," Appl. Phys. Lett. 81, 202-204 (2002).
[CrossRef]

Mayers, B. T.

D. B. Wolfe, R. S. Conroy, P. Garstecki, B. T. Mayers, M. A, Fischbach, K. E. Paul, M. Prentiss, and G. M. Whitesides, "Dynamic control of liquid-core/liquid-cladding optical waveguides," PNAS 101, 12434-12438 (2004).
[CrossRef] [PubMed]

Mookherjea, S.

U. Levy, K. Campbell, A. Groisman, S. Mookherjea, and Y. Fainman, "On-chip microfluidic tuning of an optical microring resonator," Appl. Phys. Lett. 88, 111107-111109 (2006).
[CrossRef]

K. Campbell, A. Groisman, U. Levy, L. Pang, S. Mookherjea, D. Psaltis, and Y. Fainman, "A microfluidic 2x2 optical switch," Appl. Phys. Lett. 85, 6119-6121 (2004).
[CrossRef]

Mugele, F.

F.  Mugele and J-C  Baret, "Electrowetting: from basics to applications," J. Phys. Condens. Matter  17, R705-R774 (2005).
[CrossRef]

Oh, K.W.

K.W. Oh, A. Han, and S. Bhansali, "A low-temperature bonding technique using spin-on fluorocarbon polymers to assemble Microsystems," J. Micromech. Microeng. 12, 187-191 (2002).
[CrossRef]

Pang, L.

L. Pang, U. Levy, K. Campbell, A. Groisman, and Y. Fainman, "A set of two orthogonal adaptive cylindrical lenses in a monolith elastomer device," Opt. Express 13, 9003-9013 (2005).
[CrossRef] [PubMed]

K. Campbell, A. Groisman, U. Levy, L. Pang, S. Mookherjea, D. Psaltis, and Y. Fainman, "A microfluidic 2x2 optical switch," Appl. Phys. Lett. 85, 6119-6121 (2004).
[CrossRef]

Peseux, J.

B. Berge and J. Peseux, "Variable focal lens controlled by an external voltage: an application of electrowetting," Eur. Phys. J. E 3, 159-163 (2000).
[CrossRef]

Psaltis, D.

Rockwood, T.

Rogers, J. A.

P. Mach, T. Krupenkin, S. Yang, and J. A. Rogers, "Dynamic tuning of optical waveguides with electrowetting pumps and recirculating fluid channels," Appl. Phys. Lett. 81, 202-204 (2002).
[CrossRef]

Scherer, A.

Shamai, R.

U. Levy and R. Shamai, "Tunable optofluidic devices," Microfluid Nanofluid 4, 97-105 (2007).
[CrossRef]

Smith, N. R.

Torres, J.

J. C. Galas, J. Torres, M. Belotti, Q. Kou, and Y. Chen, "Microfluidic tunable dye laser with integrated mixer and ring resonator," Appl. Phys. Lett. 86, 264101-264103 (2005).
[CrossRef]

Wolfe, D. B.

D. B. Wolfe, R. S. Conroy, P. Garstecki, B. T. Mayers, M. A, Fischbach, K. E. Paul, M. Prentiss, and G. M. Whitesides, "Dynamic control of liquid-core/liquid-cladding optical waveguides," PNAS 101, 12434-12438 (2004).
[CrossRef] [PubMed]

Yang, S.

P. Mach, T. Krupenkin, S. Yang, and J. A. Rogers, "Dynamic tuning of optical waveguides with electrowetting pumps and recirculating fluid channels," Appl. Phys. Lett. 81, 202-204 (2002).
[CrossRef]

Zhang, Z.

Appl. Phys. Lett.

K. Campbell, U. Levy, Y. Fainman, and A. Groisman, "Pressure-driven devices with lithographically fabricated composite epoxy-elastomer membranes," Appl. Phys. Lett. 89, 154105-154107 (2006).
[CrossRef]

K. Campbell, A. Groisman, U. Levy, L. Pang, S. Mookherjea, D. Psaltis, and Y. Fainman, "A microfluidic 2x2 optical switch," Appl. Phys. Lett. 85, 6119-6121 (2004).
[CrossRef]

U. Levy, K. Campbell, A. Groisman, S. Mookherjea, and Y. Fainman, "On-chip microfluidic tuning of an optical microring resonator," Appl. Phys. Lett. 88, 111107-111109 (2006).
[CrossRef]

J. C. Galas, J. Torres, M. Belotti, Q. Kou, and Y. Chen, "Microfluidic tunable dye laser with integrated mixer and ring resonator," Appl. Phys. Lett. 86, 264101-264103 (2005).
[CrossRef]

S. Kuiper and B. H. W. Hendriks, "Variable-focus liquid lens for miniature cameras," Appl. Phys. Lett. 85, 1128-1130 (2004).
[CrossRef]

P. Mach, T. Krupenkin, S. Yang, and J. A. Rogers, "Dynamic tuning of optical waveguides with electrowetting pumps and recirculating fluid channels," Appl. Phys. Lett. 81, 202-204 (2002).
[CrossRef]

Eur. Phys. J. E

B. Berge and J. Peseux, "Variable focal lens controlled by an external voltage: an application of electrowetting," Eur. Phys. J. E 3, 159-163 (2000).
[CrossRef]

J. Colloid Interface Sci.

S. Berry, J. Kedzierski, and B. Abedian, "Low voltage electrowetting using thin fluoroploymer films," J. Colloid Interface Sci. 303, 517-524 (2006).
[CrossRef] [PubMed]

J. Micromech. Microeng.

K.W. Oh, A. Han, and S. Bhansali, "A low-temperature bonding technique using spin-on fluorocarbon polymers to assemble Microsystems," J. Micromech. Microeng. 12, 187-191 (2002).
[CrossRef]

J. Phys. Condens. Matter

F.  Mugele and J-C  Baret, "Electrowetting: from basics to applications," J. Phys. Condens. Matter  17, R705-R774 (2005).
[CrossRef]

Microfluid Nanofluid

U. Levy and R. Shamai, "Tunable optofluidic devices," Microfluid Nanofluid 4, 97-105 (2007).
[CrossRef]

Nature

R. A. Hayes and B. J. Feenstra, "Video-speed electronic paper based on electrowetting," Nature 425, 383-385 (2003).
[CrossRef] [PubMed]

Opt. Express

Opt. Lett.

PNAS

D. B. Wolfe, R. S. Conroy, P. Garstecki, B. T. Mayers, M. A, Fischbach, K. E. Paul, M. Prentiss, and G. M. Whitesides, "Dynamic control of liquid-core/liquid-cladding optical waveguides," PNAS 101, 12434-12438 (2004).
[CrossRef] [PubMed]

Supplementary Material (3)

» Media 1: AVI (1678 KB)     
» Media 2: AVI (1618 KB)     
» Media 3: MOV (1964 KB)     

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Figures (8)

Fig. 1.
Fig. 1.

A schematic model of the EWOD-actuated tunable micro ring resonator. (a) Off state; No voltage is applied and the contact angle between the droplet and the hydrophobic surfaces is high. (b) On state; Voltage is applied, the contact angle is decreased and the droplet covers a larger portion of the MRRs circumference, thus changing the transmission spectrum.

Fig. 2.
Fig. 2.

Schematic cross section of the EWOD-actuated tunable MRR.

Fig. 3.
Fig. 3.

(a) Transmission spectrum of the MRR in the off (dashed blue curve) and the on (solid green curve) states, where the change occurs mainly over the ring circumference. (b, c) microscope images showing the MRR and the droplet in the off and the on states respectively. Animated presentation of these images: Media 1.

Fig. 4.
Fig. 4.

(a) Transmission spectrum of the MRR in the off (blue dashed and red dotted) and the on (solid green) states, where the modulation occurs over the coupling region. (b, c) microscope images showing the MRR and the droplet in the off and the on states respectively. Animated presentation of these images: Media 2.

Fig. 5.
Fig. 5.

Measured (solid blue curve) and calculated (dashed red curve) transmission versus voltage, starting at a resonant wavelength with the MRR partially covered by a droplet. As voltage increases the droplet spreads and covers larger portion of the ring’s circumference, resulting a shift in the MRR resonant wavelength and an increase in light transmission.

Fig. 6.
Fig. 6.

Calculated cross sections of the droplet inside the chamber at each actuation voltage. The top contact angle is constant at 109.2° and the bottom contact angle changes with voltage from 109.2° down to 84.4°. A total advancement of 58.3 μm in the droplet frontline can be seen. The calculation uses the constraints of the chamber height, constant volume of the droplet (constant surface in this 2D cross section), and circular cross section shape of the droplet.

Fig. 7.
Fig. 7.

Time response of the tunable MRR. A single sinusoidal period of the actuation voltage (green) is shown together with the recorded optical transmission in arbitrary voltage units (blue).

Fig. 8.
Fig. 8.

Single frame excerpt from a video of a droplet actuated near the coupling region of the MRR at 10 Hz (Media 3).

Equations (4)

Equations on this page are rendered with MathJax. Learn more.

Δλ=λΔneff·γneff=15500.005·0.099631.5=0.515nm
γ=Across·LwaterLtotal=0.5·3301656=0.09963
T=α2+t22αtcosθ1+α2t22αtcosθ
cosθ=cosθ0+12CγV2

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