Abstract

We report high-throughput optical coherence tomography (OCT) that offers 1,000 times higher axial scan rate than conventional OCT in the 800 nm spectral range. This is made possible by employing photonic time-stretch for chirping a pulse train and transforming it into a passive swept source. We demonstrate a record high axial scan rate of 90.9 MHz. To show the utility of our method, we also demonstrate real-time observation of laser ablation dynamics. Our high-throughput OCT is expected to be useful for industrial applications where the speed of conventional OCT falls short.

© 2012 OSA

Full Article  |  PDF Article
OSA Recommended Articles
Ultra-high-speed optical coherence tomography with a stretched pulse supercontinuum source

Sucbei Moon and Dug Young Kim
Opt. Express 14(24) 11575-11584 (2006)

High-performance multi-megahertz optical coherence tomography based on amplified optical time-stretch

Jingjiang Xu, Xiaoming Wei, Luoqin Yu, Chi Zhang, Jianbing Xu, K. K. Y. Wong, and Kevin K. Tsia
Biomed. Opt. Express 6(4) 1340-1350 (2015)

Performance of megahertz amplified optical time-stretch optical coherence tomography (AOT-OCT)

Jingjiang Xu, Xiaoming Wei, Luoqin Yu, Chi Zhang, Jianbing Xu, K. K. Y. Wong, and Kevin K. Tsia
Opt. Express 22(19) 22498-22512 (2014)

More Recommended Articles

References

  • View by:
  • Article Order
  • |
  • Year
  • |
  • Author
  • |
  • Publication
  1. D. Huang, E. A. Swanson, C. P. Lin, J. S. Schuman, W. G. Stinson, W. Chang, M. R. Hee, T. Flotte, K. Gregory, C. A. Puliafito, and J. G. Fujimoto, “Optical coherence tomography,” Science 254(5035), 1178–1181 (1991).
    [Crossref] [PubMed]
  2. D. C. Adler, Y. Chen, R. Huber, J. Schmitt, J. Connolly, and J. G. Fujimoto, “Three-dimensional endomicroscopy using optical coherence tomography,” Nat. Photonics 1(12), 709–716 (2007).
    [Crossref]
  3. R. Huber, M. Wojtkowski, and J. G. Fujimoto, “Fourier domain mode locking (FDML): a new laser operating regime and applications for optical coherence tomography,” Opt. Express 14(8), 3225–3237 (2006).
    [Crossref] [PubMed]
  4. W. Wieser, B. R. Biedermann, T. Klein, C. M. Eigenwillig, and R. Huber, “Multi-megahertz OCT: High quality 3D imaging at 20 million A-scans and 4.5 GVoxels per second,” Opt. Express 18(14), 14685–14704 (2010).
    [Crossref] [PubMed]
  5. D. Choi, H. Hiro-Oka, H. Furukawa, R. Yoshimura, M. Nakanishi, K. Shimizu, and K. Ohbayashi, “Fourier domain optical coherence tomography using optical demultiplexers imaging at 60,000,000 lines/s,” Opt. Lett. 33(12), 1318–1320 (2008).
    [Crossref] [PubMed]
  6. S. Moon and D. Y. Kim, “Ultra-high-speed optical coherence tomography with a stretched pulse supercontinuum source,” Opt. Express 14(24), 11575–11584 (2006).
    [Crossref] [PubMed]
  7. R. E. Saperstein, N. Alic, S. Zamek, K. Ikeda, B. Slutsky, and Y. Fainman, “Processing advantages of linear chirped fiber Bragg gratings in the time domain realization of optical frequency-domain reflectometry,” Opt. Express 15(23), 15464–15479 (2007).
    [Crossref] [PubMed]
  8. K. Goda, D. R. Solli, and B. Jalali, “Real-time optical reflectometry enabled by amplified dispersive Fourier transformation,” Appl. Phys. Lett. 93(3), 031106 (2008).
    [Crossref]
  9. D. Stifter, “Beyond biomedicine: a review of alternative applications and developments for optical coherence tomography,” Appl. Phys. B 88(3), 337–357 (2007).
    [Crossref]
  10. M. Wiesner, J. Ihlemann, H. H. Müller, E. Lankenau, and G. Hüttmann, “Optical coherence tomography for process control of laser micromachining,” Rev. Sci. Instrum. 81(3), 033705 (2010).
    [Crossref] [PubMed]
  11. B. G. Goode, “Optical coherence tomography: OCT aims for industrial application,” Laser Focus World. Sep. (2009).
  12. K. Goda, D. R. Solli, K. K. Tsia, and B. Jalali, “Theory of amplified dispersive Fourier transformation,” Phys. Rev. A 80(4), 043821 (2009).
    [Crossref]
  13. K. Goda, K. K. Tsia, and B. Jalali, “Serial time-encoded amplified imaging for real-time observation of fast dynamic phenomena,” Nature 458(7242), 1145–1149 (2009).
    [Crossref] [PubMed]
  14. S. Gupta and B. Jalali, “Time stretch enhanced recording oscilloscope,” Appl. Phys. Lett. 94(4), 041105 (2009).
    [Crossref]
  15. Y. Han and B. Jalali, “Photonic time-stretched analog-to-digital converter: fundamental concepts and practical considerations,” J. Lightwave Technol. 21(12), 3085–3103 (2003).
    [Crossref]
  16. J. H. Yoo, O. V. Borisov, X. Mao, and R. E. Russo, “Existence of phase explosion during laser ablation and its effects on inductively coupled plasma-mass spectroscopy,” Anal. Chem. 73(10), 2288–2293 (2001).
    [Crossref] [PubMed]
  17. C. Phipps, Laser Ablation and its Applications (Springer, 2007).

2010 (2)

W. Wieser, B. R. Biedermann, T. Klein, C. M. Eigenwillig, and R. Huber, “Multi-megahertz OCT: High quality 3D imaging at 20 million A-scans and 4.5 GVoxels per second,” Opt. Express 18(14), 14685–14704 (2010).
[Crossref] [PubMed]

M. Wiesner, J. Ihlemann, H. H. Müller, E. Lankenau, and G. Hüttmann, “Optical coherence tomography for process control of laser micromachining,” Rev. Sci. Instrum. 81(3), 033705 (2010).
[Crossref] [PubMed]

2009 (3)

K. Goda, D. R. Solli, K. K. Tsia, and B. Jalali, “Theory of amplified dispersive Fourier transformation,” Phys. Rev. A 80(4), 043821 (2009).
[Crossref]

K. Goda, K. K. Tsia, and B. Jalali, “Serial time-encoded amplified imaging for real-time observation of fast dynamic phenomena,” Nature 458(7242), 1145–1149 (2009).
[Crossref] [PubMed]

S. Gupta and B. Jalali, “Time stretch enhanced recording oscilloscope,” Appl. Phys. Lett. 94(4), 041105 (2009).
[Crossref]

2008 (2)

2007 (3)

D. Stifter, “Beyond biomedicine: a review of alternative applications and developments for optical coherence tomography,” Appl. Phys. B 88(3), 337–357 (2007).
[Crossref]

R. E. Saperstein, N. Alic, S. Zamek, K. Ikeda, B. Slutsky, and Y. Fainman, “Processing advantages of linear chirped fiber Bragg gratings in the time domain realization of optical frequency-domain reflectometry,” Opt. Express 15(23), 15464–15479 (2007).
[Crossref] [PubMed]

D. C. Adler, Y. Chen, R. Huber, J. Schmitt, J. Connolly, and J. G. Fujimoto, “Three-dimensional endomicroscopy using optical coherence tomography,” Nat. Photonics 1(12), 709–716 (2007).
[Crossref]

2006 (2)

2003 (1)

2001 (1)

J. H. Yoo, O. V. Borisov, X. Mao, and R. E. Russo, “Existence of phase explosion during laser ablation and its effects on inductively coupled plasma-mass spectroscopy,” Anal. Chem. 73(10), 2288–2293 (2001).
[Crossref] [PubMed]

1991 (1)

D. Huang, E. A. Swanson, C. P. Lin, J. S. Schuman, W. G. Stinson, W. Chang, M. R. Hee, T. Flotte, K. Gregory, C. A. Puliafito, and J. G. Fujimoto, “Optical coherence tomography,” Science 254(5035), 1178–1181 (1991).
[Crossref] [PubMed]

Adler, D. C.

D. C. Adler, Y. Chen, R. Huber, J. Schmitt, J. Connolly, and J. G. Fujimoto, “Three-dimensional endomicroscopy using optical coherence tomography,” Nat. Photonics 1(12), 709–716 (2007).
[Crossref]

Alic, N.

Biedermann, B. R.

Borisov, O. V.

J. H. Yoo, O. V. Borisov, X. Mao, and R. E. Russo, “Existence of phase explosion during laser ablation and its effects on inductively coupled plasma-mass spectroscopy,” Anal. Chem. 73(10), 2288–2293 (2001).
[Crossref] [PubMed]

Chang, W.

D. Huang, E. A. Swanson, C. P. Lin, J. S. Schuman, W. G. Stinson, W. Chang, M. R. Hee, T. Flotte, K. Gregory, C. A. Puliafito, and J. G. Fujimoto, “Optical coherence tomography,” Science 254(5035), 1178–1181 (1991).
[Crossref] [PubMed]

Chen, Y.

D. C. Adler, Y. Chen, R. Huber, J. Schmitt, J. Connolly, and J. G. Fujimoto, “Three-dimensional endomicroscopy using optical coherence tomography,” Nat. Photonics 1(12), 709–716 (2007).
[Crossref]

Choi, D.

Connolly, J.

D. C. Adler, Y. Chen, R. Huber, J. Schmitt, J. Connolly, and J. G. Fujimoto, “Three-dimensional endomicroscopy using optical coherence tomography,” Nat. Photonics 1(12), 709–716 (2007).
[Crossref]

Eigenwillig, C. M.

Fainman, Y.

Flotte, T.

D. Huang, E. A. Swanson, C. P. Lin, J. S. Schuman, W. G. Stinson, W. Chang, M. R. Hee, T. Flotte, K. Gregory, C. A. Puliafito, and J. G. Fujimoto, “Optical coherence tomography,” Science 254(5035), 1178–1181 (1991).
[Crossref] [PubMed]

Fujimoto, J. G.

D. C. Adler, Y. Chen, R. Huber, J. Schmitt, J. Connolly, and J. G. Fujimoto, “Three-dimensional endomicroscopy using optical coherence tomography,” Nat. Photonics 1(12), 709–716 (2007).
[Crossref]

R. Huber, M. Wojtkowski, and J. G. Fujimoto, “Fourier domain mode locking (FDML): a new laser operating regime and applications for optical coherence tomography,” Opt. Express 14(8), 3225–3237 (2006).
[Crossref] [PubMed]

D. Huang, E. A. Swanson, C. P. Lin, J. S. Schuman, W. G. Stinson, W. Chang, M. R. Hee, T. Flotte, K. Gregory, C. A. Puliafito, and J. G. Fujimoto, “Optical coherence tomography,” Science 254(5035), 1178–1181 (1991).
[Crossref] [PubMed]

Furukawa, H.

Goda, K.

K. Goda, D. R. Solli, K. K. Tsia, and B. Jalali, “Theory of amplified dispersive Fourier transformation,” Phys. Rev. A 80(4), 043821 (2009).
[Crossref]

K. Goda, K. K. Tsia, and B. Jalali, “Serial time-encoded amplified imaging for real-time observation of fast dynamic phenomena,” Nature 458(7242), 1145–1149 (2009).
[Crossref] [PubMed]

K. Goda, D. R. Solli, and B. Jalali, “Real-time optical reflectometry enabled by amplified dispersive Fourier transformation,” Appl. Phys. Lett. 93(3), 031106 (2008).
[Crossref]

Gregory, K.

D. Huang, E. A. Swanson, C. P. Lin, J. S. Schuman, W. G. Stinson, W. Chang, M. R. Hee, T. Flotte, K. Gregory, C. A. Puliafito, and J. G. Fujimoto, “Optical coherence tomography,” Science 254(5035), 1178–1181 (1991).
[Crossref] [PubMed]

Gupta, S.

S. Gupta and B. Jalali, “Time stretch enhanced recording oscilloscope,” Appl. Phys. Lett. 94(4), 041105 (2009).
[Crossref]

Han, Y.

Hee, M. R.

D. Huang, E. A. Swanson, C. P. Lin, J. S. Schuman, W. G. Stinson, W. Chang, M. R. Hee, T. Flotte, K. Gregory, C. A. Puliafito, and J. G. Fujimoto, “Optical coherence tomography,” Science 254(5035), 1178–1181 (1991).
[Crossref] [PubMed]

Hiro-Oka, H.

Huang, D.

D. Huang, E. A. Swanson, C. P. Lin, J. S. Schuman, W. G. Stinson, W. Chang, M. R. Hee, T. Flotte, K. Gregory, C. A. Puliafito, and J. G. Fujimoto, “Optical coherence tomography,” Science 254(5035), 1178–1181 (1991).
[Crossref] [PubMed]

Huber, R.

Hüttmann, G.

M. Wiesner, J. Ihlemann, H. H. Müller, E. Lankenau, and G. Hüttmann, “Optical coherence tomography for process control of laser micromachining,” Rev. Sci. Instrum. 81(3), 033705 (2010).
[Crossref] [PubMed]

Ihlemann, J.

M. Wiesner, J. Ihlemann, H. H. Müller, E. Lankenau, and G. Hüttmann, “Optical coherence tomography for process control of laser micromachining,” Rev. Sci. Instrum. 81(3), 033705 (2010).
[Crossref] [PubMed]

Ikeda, K.

Jalali, B.

K. Goda, K. K. Tsia, and B. Jalali, “Serial time-encoded amplified imaging for real-time observation of fast dynamic phenomena,” Nature 458(7242), 1145–1149 (2009).
[Crossref] [PubMed]

K. Goda, D. R. Solli, K. K. Tsia, and B. Jalali, “Theory of amplified dispersive Fourier transformation,” Phys. Rev. A 80(4), 043821 (2009).
[Crossref]

S. Gupta and B. Jalali, “Time stretch enhanced recording oscilloscope,” Appl. Phys. Lett. 94(4), 041105 (2009).
[Crossref]

K. Goda, D. R. Solli, and B. Jalali, “Real-time optical reflectometry enabled by amplified dispersive Fourier transformation,” Appl. Phys. Lett. 93(3), 031106 (2008).
[Crossref]

Y. Han and B. Jalali, “Photonic time-stretched analog-to-digital converter: fundamental concepts and practical considerations,” J. Lightwave Technol. 21(12), 3085–3103 (2003).
[Crossref]

Kim, D. Y.

Klein, T.

Lankenau, E.

M. Wiesner, J. Ihlemann, H. H. Müller, E. Lankenau, and G. Hüttmann, “Optical coherence tomography for process control of laser micromachining,” Rev. Sci. Instrum. 81(3), 033705 (2010).
[Crossref] [PubMed]

Lin, C. P.

D. Huang, E. A. Swanson, C. P. Lin, J. S. Schuman, W. G. Stinson, W. Chang, M. R. Hee, T. Flotte, K. Gregory, C. A. Puliafito, and J. G. Fujimoto, “Optical coherence tomography,” Science 254(5035), 1178–1181 (1991).
[Crossref] [PubMed]

Mao, X.

J. H. Yoo, O. V. Borisov, X. Mao, and R. E. Russo, “Existence of phase explosion during laser ablation and its effects on inductively coupled plasma-mass spectroscopy,” Anal. Chem. 73(10), 2288–2293 (2001).
[Crossref] [PubMed]

Moon, S.

Müller, H. H.

M. Wiesner, J. Ihlemann, H. H. Müller, E. Lankenau, and G. Hüttmann, “Optical coherence tomography for process control of laser micromachining,” Rev. Sci. Instrum. 81(3), 033705 (2010).
[Crossref] [PubMed]

Nakanishi, M.

Ohbayashi, K.

Puliafito, C. A.

D. Huang, E. A. Swanson, C. P. Lin, J. S. Schuman, W. G. Stinson, W. Chang, M. R. Hee, T. Flotte, K. Gregory, C. A. Puliafito, and J. G. Fujimoto, “Optical coherence tomography,” Science 254(5035), 1178–1181 (1991).
[Crossref] [PubMed]

Russo, R. E.

J. H. Yoo, O. V. Borisov, X. Mao, and R. E. Russo, “Existence of phase explosion during laser ablation and its effects on inductively coupled plasma-mass spectroscopy,” Anal. Chem. 73(10), 2288–2293 (2001).
[Crossref] [PubMed]

Saperstein, R. E.

Schmitt, J.

D. C. Adler, Y. Chen, R. Huber, J. Schmitt, J. Connolly, and J. G. Fujimoto, “Three-dimensional endomicroscopy using optical coherence tomography,” Nat. Photonics 1(12), 709–716 (2007).
[Crossref]

Schuman, J. S.

D. Huang, E. A. Swanson, C. P. Lin, J. S. Schuman, W. G. Stinson, W. Chang, M. R. Hee, T. Flotte, K. Gregory, C. A. Puliafito, and J. G. Fujimoto, “Optical coherence tomography,” Science 254(5035), 1178–1181 (1991).
[Crossref] [PubMed]

Shimizu, K.

Slutsky, B.

Solli, D. R.

K. Goda, D. R. Solli, K. K. Tsia, and B. Jalali, “Theory of amplified dispersive Fourier transformation,” Phys. Rev. A 80(4), 043821 (2009).
[Crossref]

K. Goda, D. R. Solli, and B. Jalali, “Real-time optical reflectometry enabled by amplified dispersive Fourier transformation,” Appl. Phys. Lett. 93(3), 031106 (2008).
[Crossref]

Stifter, D.

D. Stifter, “Beyond biomedicine: a review of alternative applications and developments for optical coherence tomography,” Appl. Phys. B 88(3), 337–357 (2007).
[Crossref]

Stinson, W. G.

D. Huang, E. A. Swanson, C. P. Lin, J. S. Schuman, W. G. Stinson, W. Chang, M. R. Hee, T. Flotte, K. Gregory, C. A. Puliafito, and J. G. Fujimoto, “Optical coherence tomography,” Science 254(5035), 1178–1181 (1991).
[Crossref] [PubMed]

Swanson, E. A.

D. Huang, E. A. Swanson, C. P. Lin, J. S. Schuman, W. G. Stinson, W. Chang, M. R. Hee, T. Flotte, K. Gregory, C. A. Puliafito, and J. G. Fujimoto, “Optical coherence tomography,” Science 254(5035), 1178–1181 (1991).
[Crossref] [PubMed]

Tsia, K. K.

K. Goda, D. R. Solli, K. K. Tsia, and B. Jalali, “Theory of amplified dispersive Fourier transformation,” Phys. Rev. A 80(4), 043821 (2009).
[Crossref]

K. Goda, K. K. Tsia, and B. Jalali, “Serial time-encoded amplified imaging for real-time observation of fast dynamic phenomena,” Nature 458(7242), 1145–1149 (2009).
[Crossref] [PubMed]

Wieser, W.

Wiesner, M.

M. Wiesner, J. Ihlemann, H. H. Müller, E. Lankenau, and G. Hüttmann, “Optical coherence tomography for process control of laser micromachining,” Rev. Sci. Instrum. 81(3), 033705 (2010).
[Crossref] [PubMed]

Wojtkowski, M.

Yoo, J. H.

J. H. Yoo, O. V. Borisov, X. Mao, and R. E. Russo, “Existence of phase explosion during laser ablation and its effects on inductively coupled plasma-mass spectroscopy,” Anal. Chem. 73(10), 2288–2293 (2001).
[Crossref] [PubMed]

Yoshimura, R.

Zamek, S.

Anal. Chem. (1)

J. H. Yoo, O. V. Borisov, X. Mao, and R. E. Russo, “Existence of phase explosion during laser ablation and its effects on inductively coupled plasma-mass spectroscopy,” Anal. Chem. 73(10), 2288–2293 (2001).
[Crossref] [PubMed]

Appl. Phys. B (1)

D. Stifter, “Beyond biomedicine: a review of alternative applications and developments for optical coherence tomography,” Appl. Phys. B 88(3), 337–357 (2007).
[Crossref]

Appl. Phys. Lett. (2)

S. Gupta and B. Jalali, “Time stretch enhanced recording oscilloscope,” Appl. Phys. Lett. 94(4), 041105 (2009).
[Crossref]

K. Goda, D. R. Solli, and B. Jalali, “Real-time optical reflectometry enabled by amplified dispersive Fourier transformation,” Appl. Phys. Lett. 93(3), 031106 (2008).
[Crossref]

J. Lightwave Technol. (1)

Nat. Photonics (1)

D. C. Adler, Y. Chen, R. Huber, J. Schmitt, J. Connolly, and J. G. Fujimoto, “Three-dimensional endomicroscopy using optical coherence tomography,” Nat. Photonics 1(12), 709–716 (2007).
[Crossref]

Nature (1)

K. Goda, K. K. Tsia, and B. Jalali, “Serial time-encoded amplified imaging for real-time observation of fast dynamic phenomena,” Nature 458(7242), 1145–1149 (2009).
[Crossref] [PubMed]

Opt. Express (4)

Opt. Lett. (1)

Phys. Rev. A (1)

K. Goda, D. R. Solli, K. K. Tsia, and B. Jalali, “Theory of amplified dispersive Fourier transformation,” Phys. Rev. A 80(4), 043821 (2009).
[Crossref]

Rev. Sci. Instrum. (1)

M. Wiesner, J. Ihlemann, H. H. Müller, E. Lankenau, and G. Hüttmann, “Optical coherence tomography for process control of laser micromachining,” Rev. Sci. Instrum. 81(3), 033705 (2010).
[Crossref] [PubMed]

Science (1)

D. Huang, E. A. Swanson, C. P. Lin, J. S. Schuman, W. G. Stinson, W. Chang, M. R. Hee, T. Flotte, K. Gregory, C. A. Puliafito, and J. G. Fujimoto, “Optical coherence tomography,” Science 254(5035), 1178–1181 (1991).
[Crossref] [PubMed]

Other (2)

B. G. Goode, “Optical coherence tomography: OCT aims for industrial application,” Laser Focus World. Sep. (2009).

C. Phipps, Laser Ablation and its Applications (Springer, 2007).

Cited By

OSA participates in Crossref's Cited-By Linking service. Citing articles from OSA journals and other participating publishers are listed here.

Alert me when this article is cited.


Figures (3)

Fig. 1
Fig. 1

Schematic of time-stretch OCT. The optical source is a mode-locked Ti:Sapphire femtosecond pulse laser that generates a broadband pulse train at a repetition rate of 90.9 MHz. The photonic time stretcher that consists of a prism-based pre-chirper and dispersive fiber maps the spectrum of each pulse into a temporal waveform which is incident onto the sample. Here each frequency component of the spectrum illuminates the sample successively in time. The back-reflected pulses from different layers of the sample are interferometrically combined with a reference pulse at the beamsplitter, resulting in an interference fringe in the time domain where the axial information of the sample is encoded. The returned pulse is directed via the optical circulator toward the high-speed photodetector and is digitized by the real-time digitizer. Inverse Fourier transformation is performed digitally on the measured temporal waveform to obtain the axial profile of the sample. Consequently, axial scanning is performed at the pulse repetition rate of 90.9 MHz. For tomographic image acquisition, an acousto-optic deflector is used for lateral scanning over the sample at 50 kHz.

Download Full Size | PPT Slide | PDF

Fig. 2
Fig. 2

Basic performance of time-stretch OCT. (a) Train of temporally dispersed pulses displayed on a high-speed oscilloscope. The interval between consecutive axial scans (pulses) is 11 ns, which corresponds to an axial scan rate of 90.9 MHz. The inset shows one-to-one mapping between the temporal waveform of one of the pulses measured by a real-time oscilloscope and the optical spectrum of the waveform measured by a conventional optical spectrum analyzer, validating photonic time-stretch in the 800 nm spectral range. (b) Single-shot point-spread functions at different imaging depths. The inset shows that the measured axial resolution is 28 μm and is in good agreement with the theoretical estimate of 21 μm.

Download Full Size | PPT Slide | PDF

Fig. 3
Fig. 3

Real-time observation of laser ablation dynamics with time-stretch OCT. (a) Schematic of the laser ablation experiment. The ablation was performed with a single 5 ns mid-infrared laser pulse focused at an angle onto the silicon sample. The 800 nm pulse train of time-stretch OCT was incident normal onto the surface through the objective lens for real-time monitoring of dynamic changes in the sample’s surface axial position during the laser ablation. (b) Dynamics of the axial profile of the ablated surface at a single transverse point. The entire axial profile sequence corresponding to the dynamics (laser-induced mass ejection) caused by the single ablation pulse was captured at an axial scan period of 11 ns in real time. The figure indicates that the sample exploded at t = 200 ns after the ablation pulse arrived at the target at t = 0 ns. The finite time delay between the ablation pulse and the sudden depth change is due to the phase-explosion effect. The standard deviation of the fluctuations in the depth of the reference layer and the ablated layer before the explosion was measured to be 54 nm, which is small relative to the laser induced changes in the axial profile of the sample. (c) Sequence of successive tomographic images with a lateral scan period of 20 μs (corresponding to the lateral scan rate of 50 kHz). The ultrafast tomographic image acquisition was made possible by our ultrafast axial scanning. (d) Axial positions at different lateral points around the ablation region indicated in Fig. 3(c). (e) Scanning electron microscope image of the ablated sample, indicating the production of the crater by the laser ablation.

Download Full Size | PPT Slide | PDF

Metrics