Emmanuel ABRAHAM

Emmanuel ABRAHAM, Professeur, university of Bordeaux, team member of Photonics & Materials, specific topics Photonics and Ultrafast Spectrocopy.

I currently work on the development of intense THz sources and their applications to linear and non linear spectroscopy. For THz generation, we use nonlinear crystals (ZnTe) and two-color air plasma using femtosecond amplified laser pulses (800 nm, 1 kHz, 35 fs, 1-5 mJ). For THz detection, we can use coherent electro-optic sampling in nonlinear crystals (ZnTe, GaP), ABCD (air biased coherent detection) technique, as well as incoherent sensors (Golay cell, pyro-electric detectors, THz camera).

One application concerns temporal ans spatial shaping of THz pulses. I developed a sensor of THz wavefront characterization. Using a deformable mirror, it is possible to correct geometric aberrations from the THz source itself or from THz optics.

In collaboration with Etienne Brasselet’s team, I am also interested in the generation and manipulation of THz vortex beams, thereby demonstrating the possibility of structuring THz beams for both fundamental and applied applications.

This work also relies on international collaborations such as Tokushima and Takamatsu Universities in Japan, and École de Technologie Supérieure in Montreal, Canada.

As a Professor of Physics, I also engage students in applying fundamental concepts from physics, mechanics, electronics, and programming through experimental projects, in order to develop their scientific and technical skills. Recently, with the help of master course students and my colleague Philippe Maire, I developed the following project:

« Experimental physics with a homemade cycling power meter: development and characterization »

We report on a comprehensive, student-oriented approach to developing a low-cost, high-performance cycling power meter that integrates knowledge from physics, mechanics, electronics, and computer science. The power meter measures the force applied by the cyclist to the pedal crank using strain gauges arranged in a Wheatstone bridge configuration. In addition, a gyroscope is used to measure pedaling cadence. Instantaneous power is analyzed using the phyphox smartphone application, and the average power is calculated and transmitted to a bike computer or smartwatch via the Cycling Power Service, a Bluetooth Low Energy profile designed for transmitting cycling power data. The averaging process can be customized by adjusting the number of pedal rotations and applying a moving average, allowing for tailored power feedback to optimize training sessions. The cycling power meter provides accurate and reliable measurements, comparable to those of a commercial sensor, with an estimated relative error better than 2%. This experimental physics project can be proposed to students at minimal cost by following the step-by-step guide provided in this article. The process encourages hands-on learning and the application of theoretical concepts in multiple disciplines, including data acquisition, signal processing, and wireless communication.

If you are interested in discovering the details of this project, please contact me by email (emmanuel.abraham@u-bordeaux.fr).

Travaux Emmanuel ABRAHAM 2

THz wavefront sensing

Vortex THz

vortex THz (vidéo)

Homemade cycling power meter

Research facilities Research topics Collaborations Publications Curriculum vitae

Research facilities

COSMAT plateform (ex COLA) : amplified CPA Ti:Sa laser source (800 nm, 1 kHz, 1-5 mJ, 35 fs)

Intense THz source: two-color air plasma + optical rectification in ZnTe or LiNbO3

Nonlinear optics, time-resolved spectroscopy

electro-optic detection

Research topics

Metrology and THz instrumentation

Wavefront sensing, THz Adaptive optics

Temporal and spatial THz pulse shaping, THz vortex

Collaborations

ALPhANOV

CEA Tech (Pessac)

Imagine Optic

SATT d’Aquitaine (AST)

Osaka University, University of Tokushima, University of Takamatsu (Japon)

Ecole de Technologie Supérieure (Québec)

Aalborg University (Danemark)

Académie de Sciences de Russie

Sidney University, Macquarie University (Australie)

Publications

List of my publications on Hal Archive

2017-2026 :

E. Abraham, T. Ogawa, M. Brossard, and T. Yasui, « Interferometric Terahertz Wavefront Analysis, » IEEE Journal of Selected Topics in Quantum Electronics 23(4), 1–5 (2017).
M. Brossard, H. Cahyadi, M. Perrin, J. Degert, E. Freysz, T. Yasui, and E. Abraham, « Direct Wavefront Measurement of Terahertz Pulses Using Two-Dimensional Electro-Optic Imaging, » IEEE Transactions on Terahertz Science and Technology 7(6), 741–746 (2017).
A. Minasyan, C. Trovato, J. Degert, E. Freysz, E. Brasselet, and E. Abraham, « Geometric phase shaping of terahertz vortex beams, » Opt. Lett. 42(1), 41 (2017).
M. Brossard, J.-F. Sauvage, M. Perrin, and E. Abraham, « Terahertz adaptive optics with a deformable mirror, » Optics Letters 43(7), 1594 (2018).
M. Yamagiwa, T. Minamikawa, C. Trovato, T. Ogawa, D. G. A. Ibrahim, Y. Kawahito, R. Oe, K. Shibuya, T. Mizuno, E. Abraham, Y. Mizutani, T. Iwata, H. Yamamoto, K. Minoshima, and T. Yasui, « Multicascade-linked synthetic wavelength digital holography using an optical-comb-referenced frequency synthesizer, » Optics Express 26(20), 26292 (2018).
A. A. Dhaybi, J. Degert, E. Brasselet, E. Abraham, and E. Freysz, « Terahertz vortex beam generation by infrared vector beam rectification, » Journal of the Optical Society of America B 36(1), 12 (2019).
C. B. Sørensen, L. Guiramand, J. Degert, M. Tondusson, E. Skovsen, E. Freysz, and E. Abraham, « Conical versus Gaussian terahertz emission from two-color laser-induced air plasma filaments, » Opt. Lett. 45(7), 2132 (2020).
J. Degert, M. Tondusson, V. Freysz, E. Abraham, S. Kumar, and E. Freysz, « Ultrafast, broadband and tunable terahertz reflector and neutral density filter based on high resistivity silicon, » Opt. Express 30(11), 18995 (2022).
D. Hakobyan, M. Hamdi, O. Redon, A. Ballestero, A. Mayaudon, L. Boyer, O. Durand, and E. Abraham, « Non-destructive evaluation of ceramic porosity using terahertz time-domain spectroscopy, » Journal of the European Ceramic Society 42(2), 525–533 (2022).
T. Yasui and E. Abraham, « Tutorial: Real-time coherent terahertz imaging of objects moving in one direction with constant speed, » Journal of Applied Physics 133(21), 211102 (2023).
L. Dalstein, M. Tondusson, M. H. Kristensen, E. Abraham, J. Degert, and E. Freysz, « Near-infrared–terahertz hyper-Raman spectroscopy of an excited silicon surface, » The Journal of Chemical Physics 161(15), 154708 (2024).
E. Hase, J. Degert, E. Freysz, T. Yasui, and E. Abraham, « Frequency-resolved measurement of two-color air plasma terahertz emission, » J. Eur. Opt. Society-Rapid Publ. 20(2), 39 (2024).
R. Blommaert, M. Franzinetti, V. Gosse, Q. Thomas, P. Maire, and E. Abraham, « Experimental physics with a homemade cycling power meter: Development and characterization, » American Journal of Physics 93(7), 589–597 (2025).
Y. Tokizane, M. H. Kristensen, S. Ohno, J. Degert, E. Freysz, E. Brasselet, T. Yasui, and E. Abraham, « Frequency-multiplexed terahertz multiple vortex beam generation, » Applied Physics Letters 126(19), 191106 (2025).
D. Kararwal, T. Guillaume, J. Degert, E. Freysz, F. Blanchard, and E. Abraham, « Spatio-spectral full-Stokes mapping of broadband terahertz pulses », submitted to Appl. Phys. Lett. (2026).

Curriculum vitae

September 2013 : Professeur, University of Bordeaux

September 1998 : Assistant professor, University of Bordeaux

1997-1998 : Postdoc, National Research Laboratory of Metrology, Tsukuba (Japon)

1994-1997 : PhD, University of Bordeaux