Gautier Papon

Silver clusters embedded in glass as a perennial high capacity optical recording medium.

[∗] Dr. A. Royon , Dr. M. Bellec , G. Papon , Dr. B. Bousquet , Prof. L. Canioni Centre de Physique Moleculaire Optique et Hertzienne University of Bordeaux 351 Cours de la Liberation, 33405 Talence (France) E-mail: l.canioni@cpmoh.u-bordeaux1.fr K. Bourhis , Dr. T. Cardinal Institut de Chimie de la Matiere Condensee de Bordeaux University of Bordeaux 87 Avenue du Docteur Schweitzer, 33608 Pessac (France) Dr. Y. Deshayes Laboratoire de l ′ Integration du Materiau au Systeme University of Bordeaux 351 Cours de la Liberation, 33405 Talence (France)

Femtosecond laser induced photochemistry in materials tailored with photosensitive agents [Invited]

This article deals with the recent advances in photochemistry in optical materials induced by femtosecond laser pulses. The field of investigation of this paper is limited to bulk solid isotropic transparent materials (glasses and polymers), specifically tailored with photoactive agents. The formation mechanisms of laser-induced color centers, nanoclusters, nanoparticles and nanocrystallites are reviewed and argued, in particular the influence of the temperature during or after the laser irradiation. The relation between the photo-induced structures and the optical property modifications are discussed, as well as some applications.

Three-dimensional direct femtosecond laser writing of second-order nonlinearities in glass

We demonstrate that direct femtosecond laser writing in silver-containing zinc and gallium phosphate glass enables generation of three-dimensional (3D) optical second-order nonlinear microstructures having an χ(2) value about 2.5 times that of quartz. The proposed physical model involves photo-reduction, photo-dissociation, and migration of silver species within the glass matrix. 3D laser-written second-order nonlinear structures could become a new class of nonlinear optical components.

Fluorescence and second-harmonic generation correlative microscopy to probe space charge separation and silver cluster stabilization during direct laser writing in a tailored silver-containing glass

We report on fluorescence and second-harmonic generation correlative microscopy of femtosecond direct laser-induced structures in a tailored silver-containing phosphate glass. We compare the spatial distributions of the related permanent electric field and silver clusters. The latter appear to be co-localized where the associated electric potential ensures favorable reduction-oxidation conditions for their formation and stabilization. Space charge separation is shown to occur prior the cluster formation. The associated electric field is a key parameter for silver clustering, thanks to electric field assisted silver ion motion. Future photonic structures combining 3D laser-structured fluorescence and nonlinear optical properties in such tailored glass will require an optimal control of the induced electric field distribution.

Femtosecond single-beam direct laser poling of stable and efficient second-order nonlinear optical properties in glass

We depict a new approach for the localized creation in three dimensions (3D) of a highly demanded nonlinear optical function for integrated optics, namely second harmonic generation. We report on the nonlinear optical characteristics induced by single-beam femtosecond direct laser writing in a tailored silver-containing phosphate glass. The original spatial distribution of the nonlinear pattern, composed of four lines after one single laser writing translation, is observed and modeled with success, demonstrating the electric field induced origin of the second harmonic generation. These efficient second-order nonlinear structures (with χeff(2) ∼ 0.6 pm V−1) with sub-micron scale are impressively stable under thermal constraint up to glass transition temperature, which makes them very promising for new photonic applications, especially when 3D nonlinear architectures are desired.

New solutions for standardization, monitoring and quality management of fluorescence-based imaging systems(Conference Presentation)

Fluorescence microscopes have become ubiquitous in life sciences laboratories, including those focused on pharmaceu¬ticals, diagnosis, and forensics. For the past few years, the need for both per¬formance guarantees and quantifiable results has driven development in this area. However, the lack of appropri¬ate standards and reference materials makes it difficult or impossible to com¬pare the results of two fluorescence mi¬croscopes, or to measure performance fluctuations of one microscope over time. Therefore, the operation of fluo¬rescence microscopes is not monitored as often as their use warrants - an is¬sue that is recognized by both systems manufacturers and national metrolo¬gy institutes. We have developed a new process that enables the etching of long-term stable fluorescent patterns with sub-micrometer sizes in three dimensions inside glass. In this paper, we present, based on this new process, a fluorescent multi-dimensional ruler and a dedicated software that are suitable for monitoring and quality management of fluorescence-based imaging systems (wide-field, confocal, multiphoton, high content machines). In addition to fluorescence, the same patterns exhibit bright- and dark-field contrast, DIC, and phase contrast, which make them also relevant to monitor these types of microscopes. Non-exhaustively, this new solution enables the measurement of: The stage repositioning accuracy; The illumination and detection homogeneities; The field flatness; The detectors’ characteristics; The lateral and axial spatial resolutions; The spectral response (spectrum, intensity and lifetime) of the system. Thanks to the stability of the patterns, microscope performance assessment can be carried out as well in a daily basis as in the long term.

Direct Laser-Writing in a silver-zinc doped phosphate glass: Spatial discrimination of aggregates - Formation mechanism

We report on spatially and spectrally-resolved linear optical properties induced by Direct Laser Writing in a prepared silver-doped phosphate glass, opening interesting possibilities for elementary photonics bricks. The formation mechanism of optical structures is proposed.

Femtosecond direct laser writing of linear and nonlinear optical properties in photosensitive glass

Glasses specifically tailored with photosensitive agents such as silver are efficient material for direct laser writing localized linear and non linear optical properties. The relation between the photo-induced structures and the modifications of the linear and optical properties are discussed.

Direct laser writing of nonlinear properties in photosensitive glass

A 1030 nm pulsed femtosecond laser has been use to induce modifications in silver containing glass namely femto-photo luminescent glass (FPL) and Photo-thermo refractive glass (PTR). The 5W 10Mhz laser is focused at a depth of 200 μm in the glass using a 0,52 NA objective. The output polarization of the laser is TM. The tailoring of the number of pulses, pulse energy and repetition rate is achieve by acousto-optic filtering. The interaction resulted in the creation of stable pipe-shaped silver clusters forming bellow refraction-limit 3D structures. Those nano-structures exhibit non-linear properties such as SHG and THG as well as fluorescence. Due to multiphoton absorption, free electrons are created in the central part of the beam, enabling the reduction of Ag+ silver ions into Ag0 and subsequently AgmX+. The cumulated thermal effect of the pulses weakens the glass matrix allowing the diffusion of the AgmX+. The ion concentration gradient creates a buried electric field enabling non-linear properties. Influences of polarization, dose and fluence on the nonlinear properties are investigated. Our explanation of the causes of SHG and THG are validated by the accordance between the theory and the measurement. Comparisons between theoretic model and our results showing accordance in the limits of out 2D model are demonstrated using different incoming polarizations.