Abstract

The use of variable-focal-length (VFL) microlenses can provide a way to axially scan the foci across a sample by electronic control. We demonstrate an approach to coupling VFL microlenses individually to a fiber bundle as a way to create a high-throughput aperture array with a controllable aperture pattern. It would potentially be applied in real-time confocal imaging in vivo for biological specimens. The VFL microlenses that we used consist of a liquid-crystal film sandwiched between a pair of conductive substrates for which one has a hole-patterned electrode. One obtains the variation of the focal length by changing the applied voltage. The fiber bundle has been characterized by coupling with both coherent and incoherent light sources. We further demonstrate the use of a VFL microlens array in combination with the fiber bundle to build up a confocal system. The axial response of the confocal system has been measured without mechanical movement of the sample or the objective, and the FWHM is estimated to be approximately 16 μm, with asymmetric sidelobes.

© 2005 Optical Society of America

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References

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    [CrossRef] [PubMed]
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    [CrossRef]
  4. T. Tanaami, Y. Sugiyama, K. Mikuriya, “High speed confocal laser microscopy,” Yokogawa Tech. Rep.19, 7–10 (Yokogawa, 9-32 Nakacho 2-chome, Musashino-shi, Tokyo, Japan, 1994).
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    [CrossRef]
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    [CrossRef]
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    [CrossRef]
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2001 (1)

P. J. Smith, C. M. Taylor, E. M. McCabe, D. R. Selviah, S. E. Day, L. G. Commander, “Switchable fiber coupling using variable-focal-length microlenses,” Rev. Sci. Instrum. 72, 3132–3134 (2001).
[CrossRef]

2000 (1)

T. Scharf, P. Kipfer, M. Bouvier, J. Grupp, “Diffraction limited liquid crystal microlenses with planar alignment,” Jpn. J. Appl. Phys. 39, 6629–6636 (2000).
[CrossRef]

1997 (1)

R. Juškaitis, T. Wilson, T. F. Watson, “Real-time white light reflection confocal microscopy using a fibre-optic bundle,” Scanning 19, 15–19 (1997).
[CrossRef]

1996 (1)

E. M. McCabe, D. T. Fewer, A. C. Ottewill, S. J. Hewlett, J. Hegarty, “Direct-view microscopy: optical sectioning strength for finite sized, multiple-pinhole arrays,” J. Microsc. 184, 95–105 (1996).
[CrossRef]

1994 (1)

1993 (1)

1991 (1)

S. Nose, S. Masuda, S. Sato, “Optical properties of a liquid crystal microlens with a symmetric electrode structure,” Jpn. J. Appl. Phys. 30, L2110–2112 (1991).
[CrossRef]

1979 (1)

S. Sato, “Liquid crystal lens-cell with variable focal length,” Jpn. J. Appl. Phy. 18, 1679–1684 (1979).
[CrossRef]

1967 (1)

M. D. Egger, M. Petráň, “New reflected-light microscope for viewing unstained brain and ganglion cells,” Science 157, 305–307 (1967).
[CrossRef] [PubMed]

Aziz, D.

Berreman, D. W.

D. W. Berreman, “Variable focus liquid crystal lens system,” U.S. patent4,190,330 (26February, 1980).

Bouvier, M.

T. Scharf, P. Kipfer, M. Bouvier, J. Grupp, “Diffraction limited liquid crystal microlenses with planar alignment,” Jpn. J. Appl. Phys. 39, 6629–6636 (2000).
[CrossRef]

Brain, K.

Commander, L. G.

P. J. Smith, C. M. Taylor, E. M. McCabe, D. R. Selviah, S. E. Day, L. G. Commander, “Switchable fiber coupling using variable-focal-length microlenses,” Rev. Sci. Instrum. 72, 3132–3134 (2001).
[CrossRef]

Day, S. E.

P. J. Smith, C. M. Taylor, E. M. McCabe, D. R. Selviah, S. E. Day, L. G. Commander, “Switchable fiber coupling using variable-focal-length microlenses,” Rev. Sci. Instrum. 72, 3132–3134 (2001).
[CrossRef]

Egger, M. D.

M. D. Egger, M. Petráň, “New reflected-light microscope for viewing unstained brain and ganglion cells,” Science 157, 305–307 (1967).
[CrossRef] [PubMed]

Fewer, D. T.

E. M. McCabe, D. T. Fewer, A. C. Ottewill, S. J. Hewlett, J. Hegarty, “Direct-view microscopy: optical sectioning strength for finite sized, multiple-pinhole arrays,” J. Microsc. 184, 95–105 (1996).
[CrossRef]

Gmitro, A. F.

Grupp, J.

T. Scharf, P. Kipfer, M. Bouvier, J. Grupp, “Diffraction limited liquid crystal microlenses with planar alignment,” Jpn. J. Appl. Phys. 39, 6629–6636 (2000).
[CrossRef]

Gu, M.

Hegarty, J.

E. M. McCabe, D. T. Fewer, A. C. Ottewill, S. J. Hewlett, J. Hegarty, “Direct-view microscopy: optical sectioning strength for finite sized, multiple-pinhole arrays,” J. Microsc. 184, 95–105 (1996).
[CrossRef]

Hewlett, S. J.

E. M. McCabe, D. T. Fewer, A. C. Ottewill, S. J. Hewlett, J. Hegarty, “Direct-view microscopy: optical sectioning strength for finite sized, multiple-pinhole arrays,” J. Microsc. 184, 95–105 (1996).
[CrossRef]

Juškaitis, R.

R. Juškaitis, T. Wilson, T. F. Watson, “Real-time white light reflection confocal microscopy using a fibre-optic bundle,” Scanning 19, 15–19 (1997).
[CrossRef]

Kipfer, P.

T. Scharf, P. Kipfer, M. Bouvier, J. Grupp, “Diffraction limited liquid crystal microlenses with planar alignment,” Jpn. J. Appl. Phys. 39, 6629–6636 (2000).
[CrossRef]

Masuda, S.

S. Nose, S. Masuda, S. Sato, “Optical properties of a liquid crystal microlens with a symmetric electrode structure,” Jpn. J. Appl. Phys. 30, L2110–2112 (1991).
[CrossRef]

McCabe, E.

E. McCabe, “Optical imaging systems,” Irish patentS99 0004 (4April2001).

McCabe, E. M.

P. J. Smith, C. M. Taylor, E. M. McCabe, D. R. Selviah, S. E. Day, L. G. Commander, “Switchable fiber coupling using variable-focal-length microlenses,” Rev. Sci. Instrum. 72, 3132–3134 (2001).
[CrossRef]

E. M. McCabe, D. T. Fewer, A. C. Ottewill, S. J. Hewlett, J. Hegarty, “Direct-view microscopy: optical sectioning strength for finite sized, multiple-pinhole arrays,” J. Microsc. 184, 95–105 (1996).
[CrossRef]

Mikuriya, K.

T. Tanaami, Y. Sugiyama, K. Mikuriya, “High speed confocal laser microscopy,” Yokogawa Tech. Rep.19, 7–10 (Yokogawa, 9-32 Nakacho 2-chome, Musashino-shi, Tokyo, Japan, 1994).

Nose, S.

S. Nose, S. Masuda, S. Sato, “Optical properties of a liquid crystal microlens with a symmetric electrode structure,” Jpn. J. Appl. Phys. 30, L2110–2112 (1991).
[CrossRef]

Ottewill, A. C.

E. M. McCabe, D. T. Fewer, A. C. Ottewill, S. J. Hewlett, J. Hegarty, “Direct-view microscopy: optical sectioning strength for finite sized, multiple-pinhole arrays,” J. Microsc. 184, 95–105 (1996).
[CrossRef]

Petrán, M.

M. D. Egger, M. Petráň, “New reflected-light microscope for viewing unstained brain and ganglion cells,” Science 157, 305–307 (1967).
[CrossRef] [PubMed]

Sato, S.

S. Nose, S. Masuda, S. Sato, “Optical properties of a liquid crystal microlens with a symmetric electrode structure,” Jpn. J. Appl. Phys. 30, L2110–2112 (1991).
[CrossRef]

S. Sato, “Liquid crystal lens-cell with variable focal length,” Jpn. J. Appl. Phy. 18, 1679–1684 (1979).
[CrossRef]

Scharf, T.

T. Scharf, P. Kipfer, M. Bouvier, J. Grupp, “Diffraction limited liquid crystal microlenses with planar alignment,” Jpn. J. Appl. Phys. 39, 6629–6636 (2000).
[CrossRef]

Selviah, D. R.

P. J. Smith, C. M. Taylor, E. M. McCabe, D. R. Selviah, S. E. Day, L. G. Commander, “Switchable fiber coupling using variable-focal-length microlenses,” Rev. Sci. Instrum. 72, 3132–3134 (2001).
[CrossRef]

Sheppard, C.

T. Wilson, C. Sheppard, Theory and Practice of Scanning Optical Microscopy (Academic, 1984).

Sheppard, C. J. R.

Smith, P. J.

P. J. Smith, C. M. Taylor, E. M. McCabe, D. R. Selviah, S. E. Day, L. G. Commander, “Switchable fiber coupling using variable-focal-length microlenses,” Rev. Sci. Instrum. 72, 3132–3134 (2001).
[CrossRef]

Sugiyama, Y.

T. Tanaami, Y. Sugiyama, K. Mikuriya, “High speed confocal laser microscopy,” Yokogawa Tech. Rep.19, 7–10 (Yokogawa, 9-32 Nakacho 2-chome, Musashino-shi, Tokyo, Japan, 1994).

Tanaami, T.

T. Tanaami, Y. Sugiyama, K. Mikuriya, “High speed confocal laser microscopy,” Yokogawa Tech. Rep.19, 7–10 (Yokogawa, 9-32 Nakacho 2-chome, Musashino-shi, Tokyo, Japan, 1994).

Taylor, C. M.

P. J. Smith, C. M. Taylor, E. M. McCabe, D. R. Selviah, S. E. Day, L. G. Commander, “Switchable fiber coupling using variable-focal-length microlenses,” Rev. Sci. Instrum. 72, 3132–3134 (2001).
[CrossRef]

Watson, T. F.

R. Juškaitis, T. Wilson, T. F. Watson, “Real-time white light reflection confocal microscopy using a fibre-optic bundle,” Scanning 19, 15–19 (1997).
[CrossRef]

Wilson, T.

R. Juškaitis, T. Wilson, T. F. Watson, “Real-time white light reflection confocal microscopy using a fibre-optic bundle,” Scanning 19, 15–19 (1997).
[CrossRef]

T. Wilson, C. Sheppard, Theory and Practice of Scanning Optical Microscopy (Academic, 1984).

Zhou, H.

Appl. Opt. (1)

J. Microsc. (1)

E. M. McCabe, D. T. Fewer, A. C. Ottewill, S. J. Hewlett, J. Hegarty, “Direct-view microscopy: optical sectioning strength for finite sized, multiple-pinhole arrays,” J. Microsc. 184, 95–105 (1996).
[CrossRef]

Jpn. J. Appl. Phy. (1)

S. Sato, “Liquid crystal lens-cell with variable focal length,” Jpn. J. Appl. Phy. 18, 1679–1684 (1979).
[CrossRef]

Jpn. J. Appl. Phys. (2)

T. Scharf, P. Kipfer, M. Bouvier, J. Grupp, “Diffraction limited liquid crystal microlenses with planar alignment,” Jpn. J. Appl. Phys. 39, 6629–6636 (2000).
[CrossRef]

S. Nose, S. Masuda, S. Sato, “Optical properties of a liquid crystal microlens with a symmetric electrode structure,” Jpn. J. Appl. Phys. 30, L2110–2112 (1991).
[CrossRef]

Opt. Lett. (1)

Rev. Sci. Instrum. (1)

P. J. Smith, C. M. Taylor, E. M. McCabe, D. R. Selviah, S. E. Day, L. G. Commander, “Switchable fiber coupling using variable-focal-length microlenses,” Rev. Sci. Instrum. 72, 3132–3134 (2001).
[CrossRef]

Scanning (1)

R. Juškaitis, T. Wilson, T. F. Watson, “Real-time white light reflection confocal microscopy using a fibre-optic bundle,” Scanning 19, 15–19 (1997).
[CrossRef]

Science (1)

M. D. Egger, M. Petráň, “New reflected-light microscope for viewing unstained brain and ganglion cells,” Science 157, 305–307 (1967).
[CrossRef] [PubMed]

Other (4)

T. Wilson, C. Sheppard, Theory and Practice of Scanning Optical Microscopy (Academic, 1984).

T. Tanaami, Y. Sugiyama, K. Mikuriya, “High speed confocal laser microscopy,” Yokogawa Tech. Rep.19, 7–10 (Yokogawa, 9-32 Nakacho 2-chome, Musashino-shi, Tokyo, Japan, 1994).

E. McCabe, “Optical imaging systems,” Irish patentS99 0004 (4April2001).

D. W. Berreman, “Variable focus liquid crystal lens system,” U.S. patent4,190,330 (26February, 1980).

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Figures (11)

Fig. 1
Fig. 1

Setups for (a) direct coupling of a fiber bundle with a He–Ne laser or a tungsten lamp, (b) a fiber bundle coupled with a microlens array, and (c) a confocal arrangement. The microlens array produces a point source array, and the fiber bundle works as a pinhole array.

Fig. 2
Fig. 2

Normalized images of the fiber bundle end when (a) tungsten incoherent light and (b) a He–Ne coherent laser source are used.

Fig. 3
Fig. 3

Intensity profile of the single fiber inside the fiber bundle coupled with (a) a tungsten lamp and (b) a He–Ne laser. Insets, the corresponding images of the coupled fiber.

Fig. 4
Fig. 4

Normalized image of (a) the VFL microlens array and (b) foci. (c) Profile of foci A and B in (b). The driving voltage (RMS) on the VFL microlenses is 2.83 V.

Fig. 5
Fig. 5

Dependence of the focal length of the microlens on the applied voltage.

Fig. 6
Fig. 6

(a) Normalized image of the microlens array transferred by the fiber bundle. (b) Intensity profile of two focal spots, A and B. The applied voltage is 1.77 V.

Fig. 7
Fig. 7

Images of focal spot A as shown in the inset of Fig. 6(b). The applied voltages are (a) 1.41, (b) 1.56, (c) 1.77, (d) 1.98, and (e) 2.26 V.

Fig. 8
Fig. 8

Normalized intensity of focal spots A and B as shown in the inset of Fig. 6(b) versus supplied average. The intensity was averaged over an area of 11 μm × 11 μm.

Fig. 9
Fig. 9

(a) Normalized image of a microlens array guided by a fiber bundle. The dotted circle corresponds to a microlens. (b) Normalized image of the focal spots with 1.77 V voltage supplied. (c) Intensity profile of the two spots, A and B, as shown in (b).

Fig. 10
Fig. 10

Normalized intensity of the spots shown in Fig. 9(b) versus supplied average. The intensity is averaged over an area of 11 μm × 11 μm.

Fig. 11
Fig. 11

(a) Normalized image of microlenses for the setup shown in Fig. 1(c). (b) Image of the focal spots with applied voltage 1.77 V. (c) Intensity profile of the two focal spots, A and B. (d) Normalized intensity of the focal spots versus supplied average. The intensity is averaged over an area of 11 μm × 11 μm that surrounds spot A or B, as shown in (b).

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