May 3, 2016

Michael Maria

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Project title,ESR1: Establishment of connection between noise and usefulness of Super-Continuum (SC) in clinical applications such as Optical Coherence Tomography (OCT)

Investigate the potential of Super-Continuum light source for Optical Coherence Tomography in Dermatology. Understand what are the particular challenge for Ultra-High Resolution Optical Coherence Tomography and how to fully exploit Super-Continuum light for medical imaging.

Current projects and research areas

  • Ultra-High Resolution Optical Coherence Tomography (UHR-OCT)
  • Noise Characterization in OCT
  • Master-Slave Interferometry
  • Skin imaging using OCT at 1300 nm
  • Supercontinuum light source


Optical Coherence Tomography (OCT) is nowadays a daily tool for Ophtalmologist, and it is slowly admitted as a very interesting tool for Dermatologists. Ultra-High Resolution (UHR) images of skin provide to doctors a fast reliable non-invasive diagnostic possibility. Using a Super-Continuum (SC) light source for OCT offers an ultra-broadband spectrum around 1300 nm which end up as the best compromise between depth penetration of light in skin and axial resolution.

Currently, I am working on developing a UHR spectrometer-based OCT system using a SC light source centered at 1270 nm using a bandwidth of 400 nm. I am more specifically working on the noise performance of such a system and also on the issue of non-linearity arising form the interferometer. Considering the first point, a good understanding of noise impact into the OCT image provide information on how to improve the SC itself and also how to optimally use it in terms of OCT input setting. Regarding the non-linearity issue, it is crucial to perfectly control and compensate for them in order to reach UHR-OCT specifications. Non-linearity issue includes the dispersion in the system, the data resampling or the non-linear swept in fast tunable laser.

Professional experience

  • March 2014 – March 2017
    Marie Curie Early stage  researcher (UBAPHODESA, FP7-PEOPLE-2013-ITN, 607627) at NKT Photonics A/S (DK) and University of Kent (UK).
  • April 2013 – September 2013
    Industrial Master Thesis at Thales Research and Technology (III-V Lab) – Palaiseau (Paris -France).
    Development of very high power laser diode emitting at 975nm, with high wall plug efficiency, wavelength stabilization for fiber laser pumping based on III-V Semiconductors
  • June 2012 – August 2012
    Internship at M1 Level at the University of Barcleona (UB) in the Applied Optics Laboratory.
    Development of a control code for microscope platform synchronised with a modulated femtosecond laser for direct writing


  • September 2009 – September 2013
    MSc in Optics at the advanced national college of applied science and technology (ENSSAT – Rennes I University) in Lannion (France) and BarcelonaTech University (Barcelona – Spain) for a student exchange of one semester with the Master in Photonics.
  • September 2007 – August 2009
    French ”Prep School” in Math, Physics and Chemistry at Lycée Pierre Mendes France in La Roche-sur-Yon (France).
  • June 2007
    French Baccalaureat with honors


List of peer review publications

  1. Optics Express (gold open access): Vol 23, Issue 11 (2015),
    • Title: “Demonstration of tolerance to dispersion of master/slave interferometry “.
    • Authors: Adrian Bradu, Michael Maria, and Adrian Gh. Podoleanu.
    • Abstract: A theoretical model is developed for the Master/Slave interferometry (MSI) that is used to demonstrate its tolerance to dispersion left uncompensated in the interferometer when evaluating distances and thicknesses. In order to prove experimentally its tolerance to dispersion, different lengths of optical fiber are inserted into the interferometer to introduce dispersion. It is demonstrated that the sensitivity profile versus optical path difference is not affected by the length of fiber left uncompensated. It is also demonstrated that the axial resolution is constant within the axial range, close to the expected theoretical resolution determined by the optical source bandwidth. Then the thickness of a glass plate is measured several times in the presence of dispersion and errors in measurements are evaluated using the MSI method and the conventional Fourier transformation (FT) based method using linearized/calibrated data. The standard deviation for thickness results obtained with the MSI is more than 5 times smaller than the standard deviation for results delivered by the conventional, FT based method.
    • Status: Published (2015).
    • Page: 14148-14161.
  1. Optics Express: (gold open access) Vol 24, Issue 3 (2016).
    • Title: “Complex master slave interferometry “,
    • Authors: Sylvain Rivet, Michael Maria, Adrian Bradu, Thomas Feuchter, Lasse Leick, and Adrian Podoleanu.
  • Abstract: A general theoretical model is developed to improve the novel Spectral Domain Interferometry method denoted as Master/Slave (MS) Interferometry. In this model, two functions, gand h are introduced to describe the modulation chirp of the channeled spectrum signal due to nonlinearities in the decoding process from wavenumber to time and due to dispersion in the interferometer. The utilization of these two functions brings two major improvements to previous implementations of the MS method. A first improvement consists in reducing the number of channeled spectra necessary to be collected at Master stage. In previous MSI implementation, the number of channeled spectra at the Master stage equated the number of depths where information was selected from at the Slave stage. The paper demonstrates that two experimental channeled spectra only acquired at Master stage suffice to produce A-scans from any number of resolved depths at the Slave stage. A second improvement is the utilization of complex signal processing. Previous MSI implementations discarded the phase. Complex processing of the electrical signal determined by the channeled spectrum allows phase processing that opens several novel avenues. A first consequence of such signal processing is reduction in the random component of the phase without affecting the axial resolution. In previous MSI implementations, phase instabilities were reduced by an average over the wavenumber that led to reduction in the axial resolution.
  • Status: Published (2016).
  • Page : 2885-2904.
  1. Optics Letters: Vol 42, Issue 22 (2017).
    • Title: “Q-switch-pumped supercontinuum for ultra-high resolution optical coherence tomography “,
    • Authors: Michael Maria, Ivan Bravo Gonzalo, Thomas Feuchter, Mark Denninger, Peter M. Moselund, Lasse Leick, Ole Bang, and Adrian Podoleanu.
    • Abstract: In this Letter, we investigate the possibility of using a commercially available 𝑄Q-switch-pumped supercontinuum (QS-SC) source, operating in the kilohertz regime, for ultra-high resolution optical coherence tomography (UHR-OCT) in the 1300 nm region. The QS-SC source proves to be more intrinsically stable from pulse to pulse than a mode-locked-based SC (ML-SC) source while, at the same time, is less expensive. However, its pumping rate is lower than that used in ML-SC sources. Therefore, we investigate here specific conditions to make such a source usable for OCT. We compare images acquired with the QS-SC source and with a current state-of-the-art SC source used for imaging. We show that comparable visual contrast obtained with the two technologies is achievable by increasing the readout time of the camera to include a sufficient number of QS-SC pulses.
    • Status: Published (2017).
    • Page : 4744-4747.
  1. Journal of Biophotonics, arXiv:1802.01341v1 []), Source: General Physics, uploaded on 2018-02-06,
    • Title: “Two Optical Coherence Tomography Systems detect Topical Gold Nanoparticles in Hair follicles, Sweat Ducts and Measure Epidermis “.
    • Authors: Mette Mogensen, Sophie Bojesen, Niels Israelsen, Michael Maria, Mikkel Jensen, Adrian Podoleanu, Ole Bang, Merete Hædersdal
    • Abstract: None
  1. Nature Scientific Reports, arXiv:1802.01313v1, 5 Feb 2018,
    • Title: “All-depth dispersion cancellation in spectral domain optical coherence tomography using numerical intensity correlations “.
    • Authors: Mikkel Jensen, Niels Israelsen, Michael Maria, Thomas Feuchter, Adrian Podoleanu, Ole Bang.
    • Abstract: In ultra-high resolution (UHR-) optical coherence tomography (OCT) group velocity dispersion (GVD) must be corrected for in order to approach the theoretical resolution limit. One approach promises not only compensation, but complete annihilation of even order dispersion effects, and that at all sample depths. This approach has hitherto been demonstrated with an experimentally demanding ’balanced detection’ configuration based on using two detectors. We demonstrate intensity correlation (IC) OCT using a conventional spectral domain (SD) UHR-OCT system with a single detector. IC-SD-OCT configurations exhibit cross term ghost images and a reduced axial range, half of that of conventional SD-OCT. We demonstrate that both shortcomings can be removed by applying a novel generic artefact reduction algorithm and using analytic interferograms. We show the superiority of IC-SD-OCT compared to conventional SD-OCT by showing how IC-SD-OCT is able to image spatial structures behind a strongly dispersive silicon wafer. Finally, we question the resolution enhancement of p2 that IC-SD-OCT is often believed to have compared to SD-OCT. We show that this is simply the effect of squaring the reflectivity profile as a natural result of processing the product of two intensity spectra instead of a single spectrum. 

List of peer review conferences:

  • World of Photonics Congress Munich: Metrology 2015, Proceedings Volume 9525, Optical Measurement Systems for Industrial Inspection IX;952509 (2015); doi: 10.1117/12.2184858,
  • Date: 21-25 June 2015.
  • Place: Munich (DE).
  • Category: Oral presentation + Conference + Exhibition.
  • Title: “Novel dispersion tolerant interferometry method for accurate measurements of displacement “.
  • Authors: A. Bradu, Maria, L. Leick, A. G. Podoleanu.
  1. Photonics West 2016, Proceedings Volume 9697, Optical Coherence Tomography and Coherence Domain Optical Methods in Biomedicine XX;96972R (2016); doi: 10.1117/12.2214753,
    • Date: 13&19 February 2016.
    • Place: San Francisco (USA).
    • Category: Poster presentation + Conference + Exhibition.
    • Title: “Broadband master-slave interferometry using a super-continuum source
    • Authors: Maria, M. J. M. Marques, C. Costa, A. Bradu, T. Feuchter, L. Leick, A. GH. Podoleanu.
  1. Photonics West 2017, Proceedings Volume 10056, Design and Quality for Biomedical Technologies X;100560O (2017); doi: 10.1117/12.2251500
    • Date: 28 January – 2 February 2017.
    • Place: San Francisco (USA).
    • Category:
    • Title: “A comparative study of noise in supercontinuum light sources for ultra-high resolution Optical Coherence Tomography “.
    • Authors: Maria, I. B. Gonzalo, M. Bondu, R. D. Engelsholm, T. Feuchter, P. M. Moselund, L. Leick, O. Bang, A. Podoleanu
  1. World of Photonics Congress Munich: ECBO, Proceedings Volume 10329, Optical Measurement Systems for Industrial Inspection X;103290I (2017); doi: 10.1117/12.2269807
    • Date: 25-26 June 2017.
    • Place: Munich (DE).
    • Category: Oral presentation + Conference + Exhibition.
    • Title: “Non-destructive testing of layer-to-layer fusion of a 3D print using ultrahigh resolution optical coherence tomography “.
    • Authors: Niels M Israelsen, Michael Maria, Thomas Feuchter, Adrian Podoleanu, Ole Bang.
  1. World of Photonics Congress Munich: ECBO, 2017 European Conference on Lasers and Electro-Optics and European Quantum Electronics Conference, (Optical Society of America, 2017), paper CH_P_3,  ISBN: 978-1-5090-6736-7

DOI: 10.1109/CLEOE-EQEC.2017.8086913

  • Date: 25-26 June 2017.
  • Place: Munich (DE).
  • Category: Poster presentation.
  • Title: “Dispersion free full range spectral intensity optical coherence tomography“.
  • Authors: Mikkel Jensen, Niels M Israelsen, Michael Maria, Thomas Feuchter, Adrian Podoleanu, Ole Bang.
  1. 2nd Canterbury Conference on OCT, SPIE 10591, 2nd Canterbury Conference on OCT with Emphasis on Broadband Optical Sources, 105910D (5 March 2018), 6-8 Sept 2017; doi: 10.1117/12.2282295;
    • Date: 6-8 September 2017.
    • Place: University of Kent (UK).
    • Category: Oral presentation.
    • Title: Resolution dependence on phase extraction by the Hilbert transform in phase calibrated and dispersion compensated ultrahigh resolution spectrometer-based OCT“.
    • Authors: M. Israelsen, M. Maria, T. Feuchter, A. Bradu, A. Podoleanu, O. Bang


  1. Photonics West 2018, not available online yet
    • Date: 27 January – 1 February 2018.
    • Place: San Francisco (USA).
    • Category:
    • Status: Accepted.
    • Title: “Q-switched based supercontinuum source towards low-cost ultra-high resolution optical coherence tomography “.
    • Authors: Michael Maria; Ivan Bravo; Thomas Feuchter, Lasse Leick, Peter Moselund, Mark Denninger; Adrian Podoleanu; Ole Bang.
  2. Photonics West 2018, SPIE 10486, Design and Quality for Biomedical Technologies XI, 104860N (19 February 2018); doi: 10.1117/12.2282412;
    • Date: 27 January – 1 February 2018
    • Place: San Francisco (USA).
    • Category:
    • Status: Published.
    • Title: “Ultra-low noise supercontinuum source for ultra-high resolution optical coherence tomography at 1300 nm “.
    • Authors: Ivan Bravo Gonzalo, Michael Maria, Rasmus Dybbro Engelsholm, Thomas Feuchter, Lasse Leick, Peter Morten Moselund, Adrian G. H. Podoleanu, Ole Bang.


  1. Photonics West 2018, not available online yet
    • Date: 27 January – 1 February 2018
    • Place: San Francisco (USA).
    • Category:
    • Status: Accepted.
    • Title: “In-vivo detection of the skin dermo-epidermal junction by ultrahigh resolution optical coherence tomography “.
    • Authors: Niels M. Israelsen, Michael Maria, Mette Mogensen, Sophie Bojesen, Mikkel Jensen, Merete Haedersdal, Adrian Podoleanu, Ole Bang.


List of further attended conferences/workshops/events

  1. 1st UBAPHODESA workshop
    • Date: 24-25 Septembre 2015.
    • Place: NKT (DK).
    • Category: Oral presentation.
    • Title: “Broadband Master-Slave Interferometry Using a supercontinuum Source
    • Authors: Michael MARIA.


  1. Mid-term review
    • Date: 22 January 2016.
    • Place: University of Kent, SPS (UK).
    • Category: Oral presentation.
    • Title: “UBAPHODESA mid-term review meeting “.
    • Authors: Michael MARIA.


  1. 2nd UBAPHODESA workshop
    • Date: 29-30 Septembre 2016.
    • Place: University of Kent, SPS (UK).
    • Category: Oral presentation.
    • Title: “Ultra High Resolution using complex Master Slave OCT “.
    • Authors: Michael Maria, Adrian Bradu, Niels M. Israelsen, Manuel Marques, Sylvain Rivet, Thomas Feuchter, Peter Moselund, Lasse Leick, Adrian Podoleanu.