Abstract

We implement the photoacoustic transmission matrix approach on a two-dimensional photoacoustic imaging system, using a 15 MHz linear ultrasound array. Using a black leaf skeleton as a complex absorbing structure, we demonstrate that the photoacoustic transmission matrix approach allows to reveal structural features that are invisible in conventional photoacoustic images, as well as to selectively control light focusing on absorbing targets, leading to a local enhancement of the photoacoustic signal.

© 2014 Optical Society of America

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References

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  1. V. Ntziachristos, Nat. Methods 7, 603 (2010).
    [CrossRef]
  2. I. M. Vellekoop and A. P. Mosk, Opt. Lett. 32, 2309 (2007).
    [CrossRef]
  3. S. M. Popoff, G. Lerosey, R. Carminati, M. Fink, A. C. Boccara, and S. Gigan, Phys. Rev. Lett. 104, 100601 (2010).
    [CrossRef]
  4. A. P. Mosk, A. Lagendijk, G. Lerosey, and M. Fink, Nat. Photonics 6, 283 (2012).
    [CrossRef]
  5. I. M. Vellekoop, E. G. Putten, A. Lagendijk, and A. P. Mosk, Opt. Express 16, 67 (2008).
    [CrossRef]
  6. C. Hsieh, Y. Pu, R. Grange, G. Laporte, and D. Psaltis, Opt. Express 18, 20723 (2010).
    [CrossRef]
  7. X. Xu, H. Liu, and L. V. Wang, Nat. Photonics 5, 154 (2011).
    [CrossRef]
  8. K. Si, R. Fiolka, and M. Cui, Nat. Photonics 6, 657 (2012).
    [CrossRef]
  9. B. Judkewitz, Y. Wang, R. Horstmeyer, A. Mathy, and C. Yang, Nat. Photonics 7, 300 (2013).
    [CrossRef]
  10. F. Kong, R. H. Silverman, L. Liu, P. V. Chitnis, K. K. Lee, and Y. Chen, Opt. Lett. 36, 2053 (2011).
    [CrossRef]
  11. P. Beard, Interface Focus 1, 602 (2011).
    [CrossRef]
  12. T. Chaigne, O. Katz, A. C. Boccara, M. Fink, E. Bossy, and S. Gigan, Nat. Photonics 8, 58 (2014).
    [CrossRef]
  13. T. Chaigne, O. Katz, J. Gateau, C. Boccara, S. Gigan, and E. Bossy, “Improving photoacoustic-guided focusing in scattering media by spectrally filtered detection,” arXiv:1310.7535 (2013).
  14. D. B. Conkey, A. M. Caravaca-Aguirre, J. D. Dove, H. Ju, T. W. Murray, and R. Piestun, “Super-resolution photoacoustic imaging through a scattering wall,” arXiv:1310.5736 (2013).
  15. P. Lai, L. Wang, J. W. Tay, and L. V. Wang, “Nonlinear photoacoustic wavefront shaping (PAWS) for single speckle-grain optical focusing in scattering media,” arXiv:1402.0816 (2014).
  16. A. M. Caravaca-Aguirre, D. B. Conkey, J. D. Dove, H. Ju, T. W. Murray, and R. Piestun, Opt. Express 21, 26671 (2013).
    [CrossRef]
  17. J. Gateau, T. Chaigne, O. Katz, S. Gigan, and E. Bossy, Opt. Lett. 38, 5188 (2013).
    [CrossRef]
  18. I. M. Vellekoop, A. D. Lagendijk, and A. P. Mosk, Nat. Photonics 4, 320 (2010).
    [CrossRef]
  19. J. Jose, R. G. H. Willemink, W. Steenbergen, C. H. Slump, T. G. van Leeuwen, and S. Manohar, Med. Phys. 39, 7262 (2012).
    [CrossRef]
  20. M. Xu and L. V. Wang, Phys. Rev. E 71, 016706 (2005).
    [CrossRef]
  21. Y. Xu, L. V. Wang, G. Ambartsoumian, and P. Kuchment, Med. Phys. 31, 724 (2004).
    [CrossRef]
  22. S. M. Popoff, G. Lerosey, M. Fink, A. C. Boccara, and S. Gigan, New J. Phys. 13, 123021 (2011).
    [CrossRef]

2014

T. Chaigne, O. Katz, A. C. Boccara, M. Fink, E. Bossy, and S. Gigan, Nat. Photonics 8, 58 (2014).
[CrossRef]

2013

2012

J. Jose, R. G. H. Willemink, W. Steenbergen, C. H. Slump, T. G. van Leeuwen, and S. Manohar, Med. Phys. 39, 7262 (2012).
[CrossRef]

A. P. Mosk, A. Lagendijk, G. Lerosey, and M. Fink, Nat. Photonics 6, 283 (2012).
[CrossRef]

K. Si, R. Fiolka, and M. Cui, Nat. Photonics 6, 657 (2012).
[CrossRef]

2011

X. Xu, H. Liu, and L. V. Wang, Nat. Photonics 5, 154 (2011).
[CrossRef]

F. Kong, R. H. Silverman, L. Liu, P. V. Chitnis, K. K. Lee, and Y. Chen, Opt. Lett. 36, 2053 (2011).
[CrossRef]

P. Beard, Interface Focus 1, 602 (2011).
[CrossRef]

S. M. Popoff, G. Lerosey, M. Fink, A. C. Boccara, and S. Gigan, New J. Phys. 13, 123021 (2011).
[CrossRef]

2010

I. M. Vellekoop, A. D. Lagendijk, and A. P. Mosk, Nat. Photonics 4, 320 (2010).
[CrossRef]

S. M. Popoff, G. Lerosey, R. Carminati, M. Fink, A. C. Boccara, and S. Gigan, Phys. Rev. Lett. 104, 100601 (2010).
[CrossRef]

C. Hsieh, Y. Pu, R. Grange, G. Laporte, and D. Psaltis, Opt. Express 18, 20723 (2010).
[CrossRef]

V. Ntziachristos, Nat. Methods 7, 603 (2010).
[CrossRef]

2008

2007

2005

M. Xu and L. V. Wang, Phys. Rev. E 71, 016706 (2005).
[CrossRef]

2004

Y. Xu, L. V. Wang, G. Ambartsoumian, and P. Kuchment, Med. Phys. 31, 724 (2004).
[CrossRef]

Ambartsoumian, G.

Y. Xu, L. V. Wang, G. Ambartsoumian, and P. Kuchment, Med. Phys. 31, 724 (2004).
[CrossRef]

Beard, P.

P. Beard, Interface Focus 1, 602 (2011).
[CrossRef]

Boccara, A. C.

T. Chaigne, O. Katz, A. C. Boccara, M. Fink, E. Bossy, and S. Gigan, Nat. Photonics 8, 58 (2014).
[CrossRef]

S. M. Popoff, G. Lerosey, M. Fink, A. C. Boccara, and S. Gigan, New J. Phys. 13, 123021 (2011).
[CrossRef]

S. M. Popoff, G. Lerosey, R. Carminati, M. Fink, A. C. Boccara, and S. Gigan, Phys. Rev. Lett. 104, 100601 (2010).
[CrossRef]

Boccara, C.

T. Chaigne, O. Katz, J. Gateau, C. Boccara, S. Gigan, and E. Bossy, “Improving photoacoustic-guided focusing in scattering media by spectrally filtered detection,” arXiv:1310.7535 (2013).

Bossy, E.

T. Chaigne, O. Katz, A. C. Boccara, M. Fink, E. Bossy, and S. Gigan, Nat. Photonics 8, 58 (2014).
[CrossRef]

J. Gateau, T. Chaigne, O. Katz, S. Gigan, and E. Bossy, Opt. Lett. 38, 5188 (2013).
[CrossRef]

T. Chaigne, O. Katz, J. Gateau, C. Boccara, S. Gigan, and E. Bossy, “Improving photoacoustic-guided focusing in scattering media by spectrally filtered detection,” arXiv:1310.7535 (2013).

Caravaca-Aguirre, A. M.

A. M. Caravaca-Aguirre, D. B. Conkey, J. D. Dove, H. Ju, T. W. Murray, and R. Piestun, Opt. Express 21, 26671 (2013).
[CrossRef]

D. B. Conkey, A. M. Caravaca-Aguirre, J. D. Dove, H. Ju, T. W. Murray, and R. Piestun, “Super-resolution photoacoustic imaging through a scattering wall,” arXiv:1310.5736 (2013).

Carminati, R.

S. M. Popoff, G. Lerosey, R. Carminati, M. Fink, A. C. Boccara, and S. Gigan, Phys. Rev. Lett. 104, 100601 (2010).
[CrossRef]

Chaigne, T.

T. Chaigne, O. Katz, A. C. Boccara, M. Fink, E. Bossy, and S. Gigan, Nat. Photonics 8, 58 (2014).
[CrossRef]

J. Gateau, T. Chaigne, O. Katz, S. Gigan, and E. Bossy, Opt. Lett. 38, 5188 (2013).
[CrossRef]

T. Chaigne, O. Katz, J. Gateau, C. Boccara, S. Gigan, and E. Bossy, “Improving photoacoustic-guided focusing in scattering media by spectrally filtered detection,” arXiv:1310.7535 (2013).

Chen, Y.

Chitnis, P. V.

Conkey, D. B.

A. M. Caravaca-Aguirre, D. B. Conkey, J. D. Dove, H. Ju, T. W. Murray, and R. Piestun, Opt. Express 21, 26671 (2013).
[CrossRef]

D. B. Conkey, A. M. Caravaca-Aguirre, J. D. Dove, H. Ju, T. W. Murray, and R. Piestun, “Super-resolution photoacoustic imaging through a scattering wall,” arXiv:1310.5736 (2013).

Cui, M.

K. Si, R. Fiolka, and M. Cui, Nat. Photonics 6, 657 (2012).
[CrossRef]

Dove, J. D.

A. M. Caravaca-Aguirre, D. B. Conkey, J. D. Dove, H. Ju, T. W. Murray, and R. Piestun, Opt. Express 21, 26671 (2013).
[CrossRef]

D. B. Conkey, A. M. Caravaca-Aguirre, J. D. Dove, H. Ju, T. W. Murray, and R. Piestun, “Super-resolution photoacoustic imaging through a scattering wall,” arXiv:1310.5736 (2013).

Fink, M.

T. Chaigne, O. Katz, A. C. Boccara, M. Fink, E. Bossy, and S. Gigan, Nat. Photonics 8, 58 (2014).
[CrossRef]

A. P. Mosk, A. Lagendijk, G. Lerosey, and M. Fink, Nat. Photonics 6, 283 (2012).
[CrossRef]

S. M. Popoff, G. Lerosey, M. Fink, A. C. Boccara, and S. Gigan, New J. Phys. 13, 123021 (2011).
[CrossRef]

S. M. Popoff, G. Lerosey, R. Carminati, M. Fink, A. C. Boccara, and S. Gigan, Phys. Rev. Lett. 104, 100601 (2010).
[CrossRef]

Fiolka, R.

K. Si, R. Fiolka, and M. Cui, Nat. Photonics 6, 657 (2012).
[CrossRef]

Gateau, J.

J. Gateau, T. Chaigne, O. Katz, S. Gigan, and E. Bossy, Opt. Lett. 38, 5188 (2013).
[CrossRef]

T. Chaigne, O. Katz, J. Gateau, C. Boccara, S. Gigan, and E. Bossy, “Improving photoacoustic-guided focusing in scattering media by spectrally filtered detection,” arXiv:1310.7535 (2013).

Gigan, S.

T. Chaigne, O. Katz, A. C. Boccara, M. Fink, E. Bossy, and S. Gigan, Nat. Photonics 8, 58 (2014).
[CrossRef]

J. Gateau, T. Chaigne, O. Katz, S. Gigan, and E. Bossy, Opt. Lett. 38, 5188 (2013).
[CrossRef]

S. M. Popoff, G. Lerosey, M. Fink, A. C. Boccara, and S. Gigan, New J. Phys. 13, 123021 (2011).
[CrossRef]

S. M. Popoff, G. Lerosey, R. Carminati, M. Fink, A. C. Boccara, and S. Gigan, Phys. Rev. Lett. 104, 100601 (2010).
[CrossRef]

T. Chaigne, O. Katz, J. Gateau, C. Boccara, S. Gigan, and E. Bossy, “Improving photoacoustic-guided focusing in scattering media by spectrally filtered detection,” arXiv:1310.7535 (2013).

Grange, R.

Horstmeyer, R.

B. Judkewitz, Y. Wang, R. Horstmeyer, A. Mathy, and C. Yang, Nat. Photonics 7, 300 (2013).
[CrossRef]

Hsieh, C.

Jose, J.

J. Jose, R. G. H. Willemink, W. Steenbergen, C. H. Slump, T. G. van Leeuwen, and S. Manohar, Med. Phys. 39, 7262 (2012).
[CrossRef]

Ju, H.

A. M. Caravaca-Aguirre, D. B. Conkey, J. D. Dove, H. Ju, T. W. Murray, and R. Piestun, Opt. Express 21, 26671 (2013).
[CrossRef]

D. B. Conkey, A. M. Caravaca-Aguirre, J. D. Dove, H. Ju, T. W. Murray, and R. Piestun, “Super-resolution photoacoustic imaging through a scattering wall,” arXiv:1310.5736 (2013).

Judkewitz, B.

B. Judkewitz, Y. Wang, R. Horstmeyer, A. Mathy, and C. Yang, Nat. Photonics 7, 300 (2013).
[CrossRef]

Katz, O.

T. Chaigne, O. Katz, A. C. Boccara, M. Fink, E. Bossy, and S. Gigan, Nat. Photonics 8, 58 (2014).
[CrossRef]

J. Gateau, T. Chaigne, O. Katz, S. Gigan, and E. Bossy, Opt. Lett. 38, 5188 (2013).
[CrossRef]

T. Chaigne, O. Katz, J. Gateau, C. Boccara, S. Gigan, and E. Bossy, “Improving photoacoustic-guided focusing in scattering media by spectrally filtered detection,” arXiv:1310.7535 (2013).

Kong, F.

Kuchment, P.

Y. Xu, L. V. Wang, G. Ambartsoumian, and P. Kuchment, Med. Phys. 31, 724 (2004).
[CrossRef]

Lagendijk, A.

A. P. Mosk, A. Lagendijk, G. Lerosey, and M. Fink, Nat. Photonics 6, 283 (2012).
[CrossRef]

I. M. Vellekoop, E. G. Putten, A. Lagendijk, and A. P. Mosk, Opt. Express 16, 67 (2008).
[CrossRef]

Lagendijk, A. D.

I. M. Vellekoop, A. D. Lagendijk, and A. P. Mosk, Nat. Photonics 4, 320 (2010).
[CrossRef]

Lai, P.

P. Lai, L. Wang, J. W. Tay, and L. V. Wang, “Nonlinear photoacoustic wavefront shaping (PAWS) for single speckle-grain optical focusing in scattering media,” arXiv:1402.0816 (2014).

Laporte, G.

Lee, K. K.

Lerosey, G.

A. P. Mosk, A. Lagendijk, G. Lerosey, and M. Fink, Nat. Photonics 6, 283 (2012).
[CrossRef]

S. M. Popoff, G. Lerosey, M. Fink, A. C. Boccara, and S. Gigan, New J. Phys. 13, 123021 (2011).
[CrossRef]

S. M. Popoff, G. Lerosey, R. Carminati, M. Fink, A. C. Boccara, and S. Gigan, Phys. Rev. Lett. 104, 100601 (2010).
[CrossRef]

Liu, H.

X. Xu, H. Liu, and L. V. Wang, Nat. Photonics 5, 154 (2011).
[CrossRef]

Liu, L.

Manohar, S.

J. Jose, R. G. H. Willemink, W. Steenbergen, C. H. Slump, T. G. van Leeuwen, and S. Manohar, Med. Phys. 39, 7262 (2012).
[CrossRef]

Mathy, A.

B. Judkewitz, Y. Wang, R. Horstmeyer, A. Mathy, and C. Yang, Nat. Photonics 7, 300 (2013).
[CrossRef]

Mosk, A. P.

A. P. Mosk, A. Lagendijk, G. Lerosey, and M. Fink, Nat. Photonics 6, 283 (2012).
[CrossRef]

I. M. Vellekoop, A. D. Lagendijk, and A. P. Mosk, Nat. Photonics 4, 320 (2010).
[CrossRef]

I. M. Vellekoop, E. G. Putten, A. Lagendijk, and A. P. Mosk, Opt. Express 16, 67 (2008).
[CrossRef]

I. M. Vellekoop and A. P. Mosk, Opt. Lett. 32, 2309 (2007).
[CrossRef]

Murray, T. W.

A. M. Caravaca-Aguirre, D. B. Conkey, J. D. Dove, H. Ju, T. W. Murray, and R. Piestun, Opt. Express 21, 26671 (2013).
[CrossRef]

D. B. Conkey, A. M. Caravaca-Aguirre, J. D. Dove, H. Ju, T. W. Murray, and R. Piestun, “Super-resolution photoacoustic imaging through a scattering wall,” arXiv:1310.5736 (2013).

Ntziachristos, V.

V. Ntziachristos, Nat. Methods 7, 603 (2010).
[CrossRef]

Piestun, R.

A. M. Caravaca-Aguirre, D. B. Conkey, J. D. Dove, H. Ju, T. W. Murray, and R. Piestun, Opt. Express 21, 26671 (2013).
[CrossRef]

D. B. Conkey, A. M. Caravaca-Aguirre, J. D. Dove, H. Ju, T. W. Murray, and R. Piestun, “Super-resolution photoacoustic imaging through a scattering wall,” arXiv:1310.5736 (2013).

Popoff, S. M.

S. M. Popoff, G. Lerosey, M. Fink, A. C. Boccara, and S. Gigan, New J. Phys. 13, 123021 (2011).
[CrossRef]

S. M. Popoff, G. Lerosey, R. Carminati, M. Fink, A. C. Boccara, and S. Gigan, Phys. Rev. Lett. 104, 100601 (2010).
[CrossRef]

Psaltis, D.

Pu, Y.

Putten, E. G.

Si, K.

K. Si, R. Fiolka, and M. Cui, Nat. Photonics 6, 657 (2012).
[CrossRef]

Silverman, R. H.

Slump, C. H.

J. Jose, R. G. H. Willemink, W. Steenbergen, C. H. Slump, T. G. van Leeuwen, and S. Manohar, Med. Phys. 39, 7262 (2012).
[CrossRef]

Steenbergen, W.

J. Jose, R. G. H. Willemink, W. Steenbergen, C. H. Slump, T. G. van Leeuwen, and S. Manohar, Med. Phys. 39, 7262 (2012).
[CrossRef]

Tay, J. W.

P. Lai, L. Wang, J. W. Tay, and L. V. Wang, “Nonlinear photoacoustic wavefront shaping (PAWS) for single speckle-grain optical focusing in scattering media,” arXiv:1402.0816 (2014).

van Leeuwen, T. G.

J. Jose, R. G. H. Willemink, W. Steenbergen, C. H. Slump, T. G. van Leeuwen, and S. Manohar, Med. Phys. 39, 7262 (2012).
[CrossRef]

Vellekoop, I. M.

Wang, L.

P. Lai, L. Wang, J. W. Tay, and L. V. Wang, “Nonlinear photoacoustic wavefront shaping (PAWS) for single speckle-grain optical focusing in scattering media,” arXiv:1402.0816 (2014).

Wang, L. V.

X. Xu, H. Liu, and L. V. Wang, Nat. Photonics 5, 154 (2011).
[CrossRef]

M. Xu and L. V. Wang, Phys. Rev. E 71, 016706 (2005).
[CrossRef]

Y. Xu, L. V. Wang, G. Ambartsoumian, and P. Kuchment, Med. Phys. 31, 724 (2004).
[CrossRef]

P. Lai, L. Wang, J. W. Tay, and L. V. Wang, “Nonlinear photoacoustic wavefront shaping (PAWS) for single speckle-grain optical focusing in scattering media,” arXiv:1402.0816 (2014).

Wang, Y.

B. Judkewitz, Y. Wang, R. Horstmeyer, A. Mathy, and C. Yang, Nat. Photonics 7, 300 (2013).
[CrossRef]

Willemink, R. G. H.

J. Jose, R. G. H. Willemink, W. Steenbergen, C. H. Slump, T. G. van Leeuwen, and S. Manohar, Med. Phys. 39, 7262 (2012).
[CrossRef]

Xu, M.

M. Xu and L. V. Wang, Phys. Rev. E 71, 016706 (2005).
[CrossRef]

Xu, X.

X. Xu, H. Liu, and L. V. Wang, Nat. Photonics 5, 154 (2011).
[CrossRef]

Xu, Y.

Y. Xu, L. V. Wang, G. Ambartsoumian, and P. Kuchment, Med. Phys. 31, 724 (2004).
[CrossRef]

Yang, C.

B. Judkewitz, Y. Wang, R. Horstmeyer, A. Mathy, and C. Yang, Nat. Photonics 7, 300 (2013).
[CrossRef]

Interface Focus

P. Beard, Interface Focus 1, 602 (2011).
[CrossRef]

Med. Phys.

J. Jose, R. G. H. Willemink, W. Steenbergen, C. H. Slump, T. G. van Leeuwen, and S. Manohar, Med. Phys. 39, 7262 (2012).
[CrossRef]

Y. Xu, L. V. Wang, G. Ambartsoumian, and P. Kuchment, Med. Phys. 31, 724 (2004).
[CrossRef]

Nat. Methods

V. Ntziachristos, Nat. Methods 7, 603 (2010).
[CrossRef]

Nat. Photonics

A. P. Mosk, A. Lagendijk, G. Lerosey, and M. Fink, Nat. Photonics 6, 283 (2012).
[CrossRef]

X. Xu, H. Liu, and L. V. Wang, Nat. Photonics 5, 154 (2011).
[CrossRef]

K. Si, R. Fiolka, and M. Cui, Nat. Photonics 6, 657 (2012).
[CrossRef]

B. Judkewitz, Y. Wang, R. Horstmeyer, A. Mathy, and C. Yang, Nat. Photonics 7, 300 (2013).
[CrossRef]

T. Chaigne, O. Katz, A. C. Boccara, M. Fink, E. Bossy, and S. Gigan, Nat. Photonics 8, 58 (2014).
[CrossRef]

I. M. Vellekoop, A. D. Lagendijk, and A. P. Mosk, Nat. Photonics 4, 320 (2010).
[CrossRef]

New J. Phys.

S. M. Popoff, G. Lerosey, M. Fink, A. C. Boccara, and S. Gigan, New J. Phys. 13, 123021 (2011).
[CrossRef]

Opt. Express

Opt. Lett.

Phys. Rev. E

M. Xu and L. V. Wang, Phys. Rev. E 71, 016706 (2005).
[CrossRef]

Phys. Rev. Lett.

S. M. Popoff, G. Lerosey, R. Carminati, M. Fink, A. C. Boccara, and S. Gigan, Phys. Rev. Lett. 104, 100601 (2010).
[CrossRef]

Other

T. Chaigne, O. Katz, J. Gateau, C. Boccara, S. Gigan, and E. Bossy, “Improving photoacoustic-guided focusing in scattering media by spectrally filtered detection,” arXiv:1310.7535 (2013).

D. B. Conkey, A. M. Caravaca-Aguirre, J. D. Dove, H. Ju, T. W. Murray, and R. Piestun, “Super-resolution photoacoustic imaging through a scattering wall,” arXiv:1310.5736 (2013).

P. Lai, L. Wang, J. W. Tay, and L. V. Wang, “Nonlinear photoacoustic wavefront shaping (PAWS) for single speckle-grain optical focusing in scattering media,” arXiv:1402.0816 (2014).

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Figures (4)

Fig. 1.
Fig. 1.

Experimental setup: a 5 ns laser pulse is shaped by an SLM before passing through a thin scattering sample and illuminating an absorbing structure. Photoacoustic signals are detected with an ultrasonic linear array, driven by an ultrasound scanner.

Fig. 2.
Fig. 2.

Improved photoacoustic imaging using the transmission matrix: (a) Reference photograph of the absorbing leaf skeleton embedded in an agarose gel block. (b) A standard photoacoustic image similar to that obtained with uniform illumination. The colored circles indicate the position of the foci presented in the next figures. (c) Envelope image derived from (b). (d) Modulation image: the value of each pixel gives the mean modulation depth of the photoacoustic signals, averaged over the input modes.

Fig. 3.
Fig. 3.

Focusing on visible regions: (a) envelope of the mean photoacoustic image [zoom of Fig. 2(c)]. (b) Envelope of the photoacoustic image when displaying specific focusing phase pattern on the SLM. (c) Envelope of the difference between the photoacoustic images corresponding to (b) and (a) (the difference is computed before the envelope). (d)–(f) and (g)–(i) are analog to (a)–(c) for different target positions. The colored squares indicate the areas over which the modulation of the photoacoustic signal was measured. The colors correspond to the positions marked in Fig. 2(b).

Fig. 4.
Fig. 4.

Focusing on invisible regions: (a) envelope of the mean photoacoustic image [zoom of Fig. 2(c)]. (b) Average of transmission matrix modulus over the input modes [zoom of Fig 2(d)]. (c) Envelope of the photoacoustic image when displaying specific focusing phase pattern on the SLM. (d) Envelope of the difference between the photoacoustic images corresponding to (c) and (a).

Metrics