Patrick Mounaix

• PhD in microelectronics
• Senior Researcher at Université Bordeaux

This study investigates the application of terahertz frequency-modulated continuous-wave (FMCW) imaging for the non-destructive inspection of a historical enamel plate, using both reflection and transmission modes. A 300 GHz FMCW radar system was employed to capture high-resolution images of the plate’s internal and surface structures. Through opti...

Polariton scattering from the lowest A1-symmetry TO vibrational mode in lithium niobate presents a promising approach for generating THz radiations. Nevertheless, a notable challenge hindering this technique is the generation of frequencies exceeding 2 THz, primarily attributed to the gain spectrum of Lithium Niobate centered at 2 THz and the subst...

This publisher’s note contains a correction to Opt. Lett. 48, 5463 (2023)10.1364/OL.499478.

Terahertz (THz) generation via photomixing on photoconductive antenna using twin delayed chirped pulses provides a long THz pulse with a narrow bandwidth. To generate a long pulse with a broad bandwidth, we propose a new, to the best of our knowledge, method that combines two long optical pulses with opposite chirps. The pulses exhibit temporal dis...

Terahertz (THz) microscopy has attracted attention owing to distinctive characteristics of the THz frequency region, particularly non-ionizing photon energy, spectral fingerprint, and transparency to most nonpolar materials. Nevertheless, the well-known Rayleigh diffraction limit imposed on THz waves commonly constrains the resultant imaging resolu...

Terahertz (THz) generation via photomixing on photoconductive antenna using twin delayed chirped pulses provides a long THz pulse with a narrow bandwidth. To generate a long pulse with broad bandwidth, we propose a new method that combines two long optical pulses with opposite chirps. The pulses exhibit temporal distributions of their instantaneous...

Terahertz microscopy has attracted attention owing to distinctive characteristics of the THz frequency region, particularly non-ionizing photon energy, spectral fingerprint, and transparency to most nonpolar materials. Nevertheless, the well-known Rayleigh diffraction limit imposed on THz waves commonly constrains the resultant imaging resolution t...

In this paper, we present the potential of Terahertz Time-Domain Imaging (THz-TDI) as a tool to perform non-invasive 3D analysis of an ancient enamel plate manufactured by Longwy Company in France. The THz data collected in the reflection mode were processed using noise filtering procedures and an advanced imaging approach. The results validate the...

The presentation will focus on polariton parametric scattering in a waveguide made of Lithium Niobate to generate THz radiation. We highlight an emission of ultra-short THz pulse with a spectrum centered around 3 THz with a large bandwidth of 4 THz.

In this investigation, we explore the phenomenon of spectral broadening in a gas-filled hollow-core capillary induced by ultra-short pulses, with a focus on nonlinear mode coupling at a power lower than the critical power. As the pulse propagates through the capillary, the spectrum primarily broadens due to self-phase modulation, and concurrently,...

Iterative phase retrieval algorithms from multiple diffraction patterns in the terahertz (THz) frequency range are a promising tool of computational imaging capable of providing high spatial resolution of reconstructed phase images. One of the commonly used algorithms is SBMIR, which employs multiple intensity distributions of the diffraction objec...

Multiplane iterative phase retrieval is a promising approach to diffraction imaging, which accurately determines the topographic and internal characteristics of various objects. Nevertheless, the detection systems used often have a limited dynamic range, resulting in overexposure of recorded intensity distributions. In this Letter, we present a nov...

This paper reports the first accurate and physicsbased Verilog-A implementation of the fully analytic form of photocurrent in SPICE compact models for uni-traveling carrier (UTC) photodiodes (PD). To overcome the limitations of single pole network implementations for modeling frequency dependence of the photo-response, especially at frequencies bey...

Four-Wave Mixing generated from a chirped pump pulse in a photonic crystal fiber can provide large gain bandwidth and high gain value offering great parameters for ultra-short pulse amplification. However, the time to frequency distribution of the bands is an important feature to improve the maximum amplification performance. Here, we present a met...

Ce papier détaille des avancées applicatives de contrôle térahertz liées à deux technologies de radars FMCW à visée de contrôle volumique non destructif et de métrologie d’épaisseur. D’un côté, les développements d’un radar FMCW a base de multiplicateurs Schottky GaAs à 150 GHz possédant des performances à l’état de l’art sont détaillées, avec, en...

Four-wave mixing is investigated when chirped pump and signal pulses are injected in a photonic crystal fiber. The shot-to-shot stability of the amplified coherent signal was measured by using the dispersive Fourier transform method and compared with numerical simulations. We highlight that the signal-to-noise ratio (SNR) of the pulsed signal incre...

The detection and quantification of fractures in rocks, as well as the detection of lithological changes, are of particular interest in scientific fields, such as construction materials, geotechnics, reservoirs and the diagnostics of dielectric composite materials and cultural heritage objects. Therefore, different methods and techniques have been...

Terahertz technology (spanning between 0.1 and 10 THz) is now a well-established tool to achieve contactless sensing and non-destructive testing (NDT). Among the advanced approaches, THz computed tomography (THz CT) is an emerging technique for 3D reconstruction and has been extensively investigated over the last decade. This work focuses on those...

The THz pulse of a few picosecond durations have been generated and detected via optical rectification and electro-optic effect within the same ZnTe crystal. An unbalanced single-shot detection scheme was performed to characterize the signal. As a result, a multicycle signal was obtained, in which two-photon absorption and other associated nonlinea...

This paper presents the development, performance, integration, and implementation of a 150 GHz FMCW radar based on a homodyne harmonic mixing scheme for noncontact, nondestructive testing. This system offers high-dynamic-range measurement capabilities up to 100 dB and measurement rates up to 7.62 kHz. Such interesting characteristics make this syst...

This erratum reports corrections to the temporal axes in Figs. 12 and 13 of J. Opt. Soc. Am. B 39, 662 (2022)JOBPDE0740-322410.1364/JOSAB.444574.

Terahertz phase retrieval from a set of axially separated diffractive intensity distributions is a promising single-beam computational imaging technique that ensures the obtention of high spatial resolutions and phase wavefronts, but remains restricted by time-consuming data acquisition processes. In this work, we have adopted an approach, relying...

Terahertz imaging is an emerging candidate to diagnose breast cancers in a label-free manner. However, detailed terahertz analysis of early stage breast cancers is difficult to achieve owing to its low spatial resolution. In this study, utilizing a probe-less terahertz near-field microscope named scanning point terahertz source microscope, we visua...

In this paper, we numerically and experimentally investigate the four-wave mixing process in a gas-filled hollow-core capillary in the femtosecond regime. The interaction between a visible broadband continuum and a chirped pump pulse resulted in the generation of a tunable near-infrared pulse of 1.2 to 1.5 µm and with the potential to reach the mid...

Le domaine térahertz aussi appelé « infrarouge lointain », reste une zone du spectre électromagnétique peu utilisée par les industriels. La cause principale est un manque certain de sources et de détecteurs compacts et performants, compatibles avec les exigences industrielles. Avec les avancées sur l’électronique ultra-haute fréquence et l’optique,...

Four wave mixing is investigated when chirped pump and signal pulses are injected in a photonic crystal fiber. The shot-to-shot stability of the amplified coherent signal was measured by using the dispersive Fourier transform method.

Four Wave Mixing band spectrogram has been retrieved from single shot spectra when a chirped pulse is injected in a fiber. This method leads to the seed chirp required for a large gain bandwidth.

Terahertz imaging is an emerging candidate to diagnose breast cancers in a label-free manner. However, detailed terahertz analysis of early stage breast cancers is difficult to achieve owing to its low spatial resolution. In this study, utilizing a probe-less terahertz near-field microscope named scanning point terahertz source microscope, we visua...

Due to the continuous increase in data traffic, it is becoming imperative to develop communication systems capable of meeting the throughput requirements. Monolithic Opto-Electronic Integrated Circuits (OEICs) are ideal candidates to meet these demands. With that in mind, we propose a compact and computationally efficient model for Uni-Traveling Ca...

Open Source Terahertz imagning setup. Terahertz and millimeter waves technologies have followed to a decade of strong development, thanks to leading promising applications fields such as hyper-spectral imaging, non-destructive testing and spectroscopy. However, the generally high cost of such systems limits their use to academic research laboratori...

The usability of terahertz systems for specific inspection tasks and imaging in the aeronautics industry is assessed. Especially, we demonstrate the suitability of Frequency-modulated continuous-wave (FMCW) radars for health monitoring and see-through imaging. Additionally, terahertz time-domain data processing is performed for multi-layered paint...

Terahertz-light imaging is attracting great attention as a new approach in non-invasive/non-staining biopsy of cancerous tissues. Positively, terahertz light has been shown to be sensitive to the cell density, the hydration content, and the chemical composition of biological samples. However, the spatial resolution of terahertz imaging is typically...

We show numerically that ultra-short pulses can be generated in the mid-infrared when a gas filled hollow-core fiber is pumped by a fundamental pulse and its second harmonic. The generation process originates from a cascaded nonlinear phenomenon starting from a spectral broadening of the two pulses followed by an induced phase-matched four wave-mix...

This paper reports investigations led on the combination of the refractive index and morphological dilation to enhance performances towards breast tumour margin delineation during conserving surgeries. The refractive index map of invasive ductal and lobular carcinomas were constructed from an inverse electromagnetic problem. Morphological dilation...

This review paper reports the prerequisites of a monolithic integrated terahertz (THz) technology capable of meeting the network capacity requirements of beyond-5G wireless communications system (WCS). Keeping in mind that the terahertz signal generation for the beyond-5G networks relies on the technology power loss management, we propose a single...

Oil shale is an unconventional source of fuel distributed across the world with only few active explorations due to the competitive advantage price of crude oil and natural gas. However, oil shale holds important application in the context of a decline in the crude oil reserves and a spike in the oil prices. In order to prepare for the futuristic t...

In this work, we investigate the modal four waves mixing (FWM) process in an argon filled capillary appearing from the spectral broadening of a pump pulse injected in the fundamental mode. The edge of the spectrum at the low wavelength part seeds the FWM process to generate and high order mode in the near infrared.

We numerically show that when a gas filled hollow-core photonic crystal fiber is pumped by two-color pulses, an ultra-short pulse can be generated in the mid-infrared. This phenomenon is due to the cascaded nonlinear phenomenon starting from a spectral broadening of the two pulses combined with an induced phase-matched four wave-mixing lying in the...

Terahertz (THz) imaging has a potential to intraoperatively diagnose breast cancers in a label-free manner [1].

This work describes the promising approach for the diagnostic of diseases, such as diabetes, by using the THz spectroscopy and THz holography method. In this paper, dry pellets consisting of human blood plasma (normal and diabetic) were designed; these objects were analyzed in various THz Russian laboratories, PCA-analysis of THz spectra was applie...

Imaging with terahertz (THz) waves has been expected as a non-invasive/non-staining visualization tool for breast cancer margins during surgeries. Breast cancer is a generic name for a heterogeneous lesion comprising invasive adenocarcinoma, in situ adenocarcinoma, most frequently in the form of ductal carcinoma in situ (DCIS) and benign tissues. U...

We report on advance developments of terahertz system data analysis for measuring the thicknesses of multiple films for non-contact control in heritage science. We provide the analysis of time-domain data regarding the measurements conducted on a French Renaissance painting realized on a copper substrate. The piece of art is made of a varnish layer...

Terahertz phase retrieval is a promising technique able to assess the complex diffracted wave properties through an iterative processing algorithm. In this Letter, we demonstrate the implementation of this technique in reflection geometry with a continuous wave acquisition system working at 0.287 THz. To ensure a high signal-to-noise ratio in the m...

A new method for diagnosis of diabetes mellitus is proposed, which uses for measurement a lyophilized blood plasma sample prepared in the form of a pellet. The paper develops a methodology for fast spectroscopic measurements of such pellets with terahertz pulse time-domain holography. For that reason, blood plasma pellets were experimentally measur...

Terahertz technologies are attracting strong interest from high-end industrial fields, and particularly for non-destructive-testing purposes. Currently lacking compactness, integrability as well as adaptability for those implementations, the development and commercialisation of more efficient sources and detectors progressively ensure the transitio...

Monolithic optoelectronic integrated circuits, OEICs are seen as key enabling technologies to minimal power loss criteria. Monolithic OEICs combine, on the same die, cutting-edge optical devices and high speed III-V electronics able to generate terahertz signal targeting beyond-5G networks. Computationally efficient compact models compatible with e...

Developments toward the implementation of a terahertz pulse imaging system within a guided reflectometry configuration are reported. Two photoconductive antennas patterned on the same LT-GaAs active layer in association with a silica pipe hollow-core waveguide allowed us to obtain a guided optics-free imager. Besides working in a pulsed regime, the...

We report a tunable source that generates pulses in the infrared from an optical parametric amplification in a gas-filled hollow core capillary based on four-wave mixing process, in which the phase matching strongly depends on the gas pressure and the pump. In our case, we have generated pulses from 1 to 1.6 m in the sub-µJ level together with a pa...

Phase Retrieval at the frequency 0.287 THz is demonstrated through the simulations and the experiments. Single Beam Multiple Intensity Reconstruction algorithm was applied to obtain phase and amplitude images from the set of diffraction patterns.

We developed a scanning laser terahertz (THz) near-field reflection imaging system using a fiber-coupled femtosecond laser source for high spatial resolution measurements without any sub-wavelength probes. In this system, THz wave pulses generated at the laser focusing spot in a non-linear optical crystal interact with a sample set on the crystal....

Monolithic optoelectronic integrated circuits (OEICs) are seen as key enabling technologies for future terahertz communications and upcoming beyond-5G networks. Co-design of monolithic OEICs requires computationally efficient compact models compatible with existing methodology/tool/design flow for timely and cost-effective realization of OEICs. Thi...

Terahertz time-domain spectroscopy is a specifically appropriated technique to analyze layered structure composition and dimension. Inverse electromagnetic problems are commonly solved to extract, from a recorded terahertz-signal, the distinctive layer dielectric properties and thicknesses. However, main origins and formation routes of the signal a...

Terahertz spectroscopy, a non-invasive and non-destructive analytical technique used in art conservation and restoration, can provide compelling data concerning the composition and condition of culturally valuable and historical objects. Terahertz spectral databases of modern and ancient artists’ pigments exist, but lack explanations for the origin...

Thanks to significant advances in real-time terahertz imaging in terms of resolution and image quality, adapting and extending optical methods for 3D imaging at the millimeter scale is now promising. The shape-from-focus algorithm is a post-processing tool used in optical microscopy to reconstruct the external shape surface of a convex surface obje...

Using the THz-PTDH method we have created the theoretical model and experimental set up for phase imaging of breast tissue sample and designed the image reconstruction procedure suitable for a cancer diagnostics.

We developed a scanning laser terahertz near-field reflection microscope and succeeded in getting high-spatial resolution terahertz images of breast cancer tissue. These images will help us to accurately detect canceration dynamics and tumor margins.

Full-field terahertz imaging suffers both from a limited contrast dynamic and from interference fringes, due to the source coherency. We propose a solution to both, homogeneously illuminate a selected area, and control the contrast dynamic and acquisition time trade-off thanks to a double mirror galvanometer.

This paper presents a fully integrated system-on-a-chip for real-time terahertz super-resolution near-field imaging. The chip consists of 128 sensing pixels with individual cross-bridged double 3-D split-ring resonators arranged in a 3.2 mm long $2\times 64$ 1-D array. It is implemented in 0.13- $\mu \text{m}$ SiGe bipolar complementary metal–oxi...

Terahertz spectroscopy is an excellent tool for the nondestructive and non-invasive investigation of pigments in historical and art objects. The characteristic terahertz spectra of solid azurite, malachite, and verdigris are presented here, along with fully quantum mechanical simulations of their crystalline structures and lattice vibrations. The p...