Data set and images from Laser direct writing of silver clusters-based subwavelength periodic structures embedded in mid-infrared gallo-germanate glass - Publication : Guérineau T., Fargues A., Lapointe J., Vallée R., Messaddeq Y., Canioni L., Petit Y. and Cardinal T. Laser direct writing of silver clusters-based subwavelength periodic structures embedded in mid-infrared gallo-germanate glass. Advanced Photonics Research 2022 vol. 3, n° 10, p. 2200032 (13 p.). DOI : 10.1002/adpr.202200032 / HAL : https://hal.archives-ouvertes.fr/hal-03682520 In the project context : ANR ArchiFLUO - Architectures photoniques intégrées inscrites par laser femtoseconde pour étalonnage en microscopie de fluorescence dans l’infrarouge - ANR-19-CE08-0021 - AAPG2019 - 2019.

Dataset production context : The direct laser writing (DLW) using femtosecond lasers allows for the inscription of 3D microstructures embedded inside optical materials. Based solely on the silver ions photochemistry, the DLW in silver-containing glasses enables to locally induce inside glasses a unique combination of optical properties. The physical modifications of the material encompass not only a refractive index change, but also new physical properties like fluorescence, second- and third-harmonic generations, and surface plasmon resonance. Numerous efforts are deployed to develop the DLW-assisted silver photochemistry in phosphate glasses. However, this glass family is suffering from its near-infrared optical cutoff as opposed to the silver-doped gallo-germanate glasses. With an extended mid-infrared (mid-IR) transmission, these glasses are synthesized via the melt-quenching technique. Depending on the glass composition, either a glass matrix-based single track (Type I) or a silver cluster-based double track (Type A) of refractive index change is produced. By enabling an order of magnitude smaller structures than with Type I, Type A modification is further expanded to embed, for the first time, periodic structures below the inter-track spacing. Demonstrated with a pitch down to 400 nm, these Type A–based periodic structures bring new insights through the fabrication of 3D diffractive gratings in mid-IR glasses.

Descriptions : datas, images, "read me"

Raw data Raman spectra and linear absorption coefficient for both GGBK and BGGK. Inset: Magnification of the UV–blue wavelength domain. Figure 1 and csv Data
"Read me" : Raman spectra were recorded at room temperature from 200 to 1000 cm-1 with a resolution of 2.5 cm-1 using a LABRAM 800-HR Raman spectrometer (Horiba Jobin Yvon) and a microscope objective 50, NA 0.75. The excitation source is a single longitudinal mode laser at 532nm. The UV–visible–near-IR transmission spectra from 200 to 2500 nm were recorded on a Cary 5000 (Varian) spectrometer by steps of 1 nm, while the near-IR-mid-IR transmission spectra were obtained from 2.5 to 7 μm using a Fourier-transform infrared spectrometer with an accumulation of 200 scans and a resolution of 4 cm-1.

Excitation and emission spectra obtained at 350 and 450 nm, and at 270 and 320 nm, respectively, for a) GGBK and b) BGGK. Time-resolved spectroscopy of the BGGK glass under a laser excitation of 355 nm: c) spectra extracted from the nanosecond and microsecond lifetimes; d) long and short (inset) lifetimes obtained from the global spectral integration. Figure 2 and csv Data
"Read me" : The steady-state excitation and emission spectra were recorded with a SPEX Fluorolog-2 spectrofluorometer (Horiba Jobin Yvon) on glass pow- der. Each spectrum was conducted with a step and resolution of 1 nm, and at room temperature. The excitation source was a 450 W xenon lamp hav- ing a continuous excitation from 200 to 800 nm. To detect and amplify the luminescence signal, a Hamamatsu R298 photomultiplier was employed. The decay time results were extracted from time-resolved spectroscopy. A Continuum Surelite SL II-10 laser was used as a pulsed 355 nm excitation source (10 Hz, 70 mJ, 4–6 ns) followed by a half-wave plate and a polarized beam splitter to control the laser fluence, ensuring that the measurement behaves only as an excitation regime in a lifetime-probing regime (and not in an irradiance regime that would lead to glass modifications). Emission spectra were recorded using a monochromator and a gated intensified charge-coupled device (ICCD) camera (Andor) being optically triggered by the pulsed UV laser.

a) Confocal fluorescence imaging of the scan speed–irradiance matrix in BGGK glass with excitation at 405 nm; b) evolution of the integrated fluorescence imaging of all the photoinduced structures as a function of the translation speed and irradiance in the BGGK glass.Figure 3 and csv Data
"Read me" : Confocal fluorescence imaging was performed using a Leica DM6 CFS TCS SP8 confocal microscope equipped with a 405nm laser diode. Microscope objectives 10x, NA 0.3 DRY and 63x, NA 1.4 OIL were used. Confocal fluorescence imaging was also performed using a Leica SP2 confocal microscope using a 405 nm laser diode to determine DLW structure height of the glasses, using a 100x, NA 1.4 OIL microscope objective.

High-resolution imaging of both confocal fluorescence and phase contrast microscopies for photo-inscribed structures at a,d) 7.8 TW cm−2, 50 μm s−1 in GGBK, and at b,e) 8.4 TW cm−2, 50 μm s−1, and c,f) 6.8 TW cm−2, 50 μm s−1 in BGGK; superposition of both fluorescence intensity and refractive index variation profiles for g) 7.8 TW cm−2, 50 μm s−1 direct laser writing (DLW) structure in GGBK, and h) 8.4 TW cm−2, 50 μm s−1 DLW structure and f) 6.8 TW cm−2, 50 μm s−1 DLW structure in BGGK, extracted from images (a–f) at the location of the gray dashed lines. Figure 4 and csv Data
"Read me" : Confocal fluorescence imaging was performed using a Leica DM6 CFS TCS SP8 confocal microscope equipped with a 405nm laser diode. Microscope objectives 10x, NA 0.3 DRY and 63x, NA 1.4 OIL were used. Confocal fluorescence imaging was also performed using a Leica SP2 confocal microscope using a 405 nm laser diode to determine DLW structure height of the glasses, using a 100x, NA 1.4 OIL microscope objective. The refractive index modifications of the DLW structures were recorded using a phase-contrast microscopy equipped with a commercial SID4Bio Phasics camera and a microscope objective (100x, NA 1.3 OIL).

Normalized a) microabsorption and b) fluorescence spectra of DLW structures inscribed at 7.8 TW cm−2, 50 μm s−1 for GGBK glass, and at 8.4 TW cm−2, 50 μm s−1 and 6.8 TW cm−2, 50 μm s−1 for BGGK glass. Figure 5 and csv Data
"Read me" : Microluminescence was conducted with a LABRAM 800-HR spectropho- tometer (Horiba Jobin-Yvon) and an Olympus microscope objective (50x, NA 0.75) using an excitation laser diode at 405nm (100mW, TEM00, OBIS, COHERENT). Microluminescence spectra were recorded thanks to a thermoelectric cooled charge-coupled device (CCD) Camera (Synapse Model 354 308). The experimental spectra were corrected from the detection arm spectral response by a correction function determined using reference samples with broad spectral emission, while the pristine glass luminescence was subtracted from the recorded spectra. Microabsorption spectra were recorded using a “CRAIC Technologies” microspectrophotome- ter equipped with a Xenon lamp, a condenser, and a 10x microscope objective. Using this appliance, the obtained results consist directly of differential absorption spectra with a subtraction of the pristine glass absorption.

Structures photo-inscribed at 7.3 TW cm−2 and 100 μm s−1 with a pitch of 2 μm, 1 μm, and 400 nm in BGGK glass. High-resolution confocal fluorescence imaging on the top under laser excitation wavelength of 405 nm and phase-contrast microscopy at the bottom. Each square structure has a length of 50 μm. Figure 6
"Read me" : Confocal fluorescence imaging was performed using a Leica DM6 CFS TCS SP8 confocal microscope equipped with a 405nm laser diode. Microscope objectives 10x, NA 0.3 DRY and 63x, NA 1.4 OIL were used. Confocal fluorescence imaging was also performed using a Leica SP2 confocal microscope using a 405 nm laser diode to determine DLW structure height of the glasses, using a 100x, NA 1.4 OIL microscope objective. The refractive index modifications of the DLW structures were recorded using a phase-contrast microscopy equipped with a commercial SID4Bio Phasics camera and a microscope objective (100x, NA 1.3 OIL).

Periodicity analyses of the a) 2 μm pitch structure recorded by phase-contrast imaging and b) 400 nm pitch structure recorded with the high-resolution fluorescence imaging. Both structures have been photoinscribed at 7.3 TW cm−2 and 100 μm s−1 in the BGGK glass. Figure 7 and csv Data
Read me" : The refractive index modifications of the DLW structures were recorded using a phase-contrast microscopy equipped with a commercial SID4Bio Phasics camera and a microscope objective (100x, NA 1.3 OIL).

Linear absorption coefficient spectra of the DLW structure inscribed at 7.8 TW cm-2 – 50 μm s-1 for GGBK glass (red curve) and its simulated counterpart (blue curve) based on the Maxwell-Garnett theory. Supplementary materials and csv Data

Excel, 2016