Thermally Resilient Planar Waveguides in Novel nc-YSZ Transparent Ceramic by fs Laser Pulses

We report on thermally resilient planar waveguides fabricated on nc-YSZ by direct fs-laser inscription in transparent nc-yttria stabilized zirconia (nc-YSZ) polycrystalline ceramic. The waveguides consisted of rectangular sections (4.5 × 2 mm2) on the surface of the sample. Optical characterization at 633 and 810 nm was performed. We estimate a laser-induced refractive index contrast of 10–4. Post-waveguide-fabrication thermal annealing treatments at 750°C for 24 h were carried out to test the resilience of the waveguides and to further reduce the waveguide losses. Both micro-Raman spectroscopy and XPS characterization revealed unmodified lattice and steady chemical features, which are consistent with the waveguide thermal resilience. Our results suggest a promising potential use of nc-YSZ in harsh and high temperature demanding photonic environments.

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Laser-induced thermal grating spectroscopy based on femtosecond laser multi-photon absorption

Scientific Reports ◽

10.1038/s41598-021-89269-2 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Maria Ruchkina ◽

Dina Hot ◽

Pengji Ding ◽

Ali Hosseinnia ◽

Per-Erik Bengtsson ◽

...

Keyword(s):

Continuous Wave ◽

Laser Pulses ◽

Photon Absorption ◽

Gas Flows ◽

Single Shot ◽

Photon Excitation ◽

Fs Laser ◽

Thermal Grating ◽

Grating Spectroscopy ◽

First Time

AbstractLaser-induced grating spectroscopy (LIGS) is for the first time explored in a configuration based on the crossing of two focused femtosecond (fs) laser pulses (800-nm wavelength) and a focused continuous-wave (cw) laser beam (532-nm wavelength). A thermal grating was formed by multi-photon absorption of the fs-laser pulses by $$\hbox {N}_{{2}}$$ N 2 with a pulse energy around 700 $$\upmu $$ μ J ($$\sim $$ ∼ 45 TW/$$\hbox {cm}^{2}$$ cm 2 ). The feasibility of this LIGS configuration was investigated for thermometry in heated nitrogen gas flows. The temperature was varied from room temperature up to 750 K, producing strong single-shot LIGS signals. A model based on the solution of the linearized hydrodynamic equations was used to extract temperature information from single-shot experimental data, and the results show excellent agreement with the thermocouple measurements. Furthermore, the fluorescence produced by the fs-laser pulses was investigated. This study indicates an 8-photon absorption pathway for $$\hbox {N}_{{2}}$$ N 2 in order to reach the $$\hbox {B}^{3}\Pi _{g}$$ B 3 Π g state from the ground state, and 8 + 5 photon excitation to reach the $$\hbox {B}^{2}\Sigma _{u}^{+}$$ B 2 Σ u + state of the $$\hbox {N}_{2}^{+}$$ N 2 + ion. At pulse energies higher than 1 mJ, the LIGS signal was disturbed due to the generation of plasma. Additionally, measurements in argon gas and air were performed, where the LIGS signal for argon shows lower intensity compared to air and $$\hbox {N}_{{2}}$$ N 2 .

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Optical Sensitivity of Waveguides Inscribed in Nanoporous Silicate Framework

Nanomaterials ◽

10.3390/nano11010123 ◽

2021 ◽

Vol 11 (1) ◽

pp. 123

Author(s):

Zhong Lijing ◽

Roman A. Zakoldaev ◽

Maksim M. Sergeev ◽

Andrey B. Petrov ◽

Vadim P. Veiko ◽

...

Keyword(s):

Refractive Index ◽

Near Field ◽

Experimental Studies ◽

Laser Pulses ◽

Femtosecond Laser Pulses ◽

Direct Writing ◽

Sensor Applications ◽

Refractive Index Contrast ◽

Optical Sensitivity ◽

Index Contrast

Laser direct writing technique in glass is a powerful tool for various waveguides’ fabrication that highly develop the element base for designing photonic devices. We apply this technique to fabricate waveguides in porous glass (PG). Nanoporous optical materials for the inscription can elevate the sensing ability of such waveguides to higher standards. The waveguides were fabricated by a single-scan approach with femtosecond laser pulses in the densification mode, which resulted in the formation of a core and cladding. Experimental studies revealed three types of waveguides and quantified the refractive index contrast (up to Δn = 1.2·10−2) accompanied with ~1.2 dB/cm insertion losses. The waveguides demonstrated the sensitivity to small objects captured by the nanoporous framework. We noticed that the deposited ethanol molecules (3 µL) on the PG surface influence the waveguide optical properties indicating the penetration of the molecule to its cladding. Continuous monitoring of the output near field intensity distribution allowed us to determine the response time (6 s) of the waveguide buried at 400 µm below the glass surface. We found that the minimum distinguishable change of the refractive index contrast is 2 × 10−4. The results obtained pave the way to consider the waveguides inscribed into PG as primary transducers for sensor applications.

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Dual-shot dynamics and ultimate frequency of all-optical magnetic recording on GdFeCo

Light Science & Applications ◽

10.1038/s41377-020-00451-z ◽

2021 ◽

Vol 10 (1) ◽

Author(s):

Sicong Wang ◽

Chen Wei ◽

Yuanhua Feng ◽

Hongkun Cao ◽

Wenzhe Li ◽

...

Keyword(s):

Magnetization Reversal ◽

Energy Efficient ◽

High Speed ◽

Data Transfer ◽

Laser Pulses ◽

Time Resolved ◽

All Optical ◽

Fs Laser ◽

High Speed Data ◽

Natural Way

AbstractAlthough photonics presents the fastest and most energy-efficient method of data transfer, magnetism still offers the cheapest and most natural way to store data. The ultrafast and energy-efficient optical control of magnetism is presently a missing technological link that prevents us from reaching the next evolution in information processing. The discovery of all-optical magnetization reversal in GdFeCo with the help of 100 fs laser pulses has further aroused intense interest in this compelling problem. Although the applicability of this approach to high-speed data processing depends vitally on the maximum repetition rate of the switching, the latter remains virtually unknown. Here we experimentally unveil the ultimate frequency of repetitive all-optical magnetization reversal through time-resolved studies of the dual-shot magnetization dynamics in Gd27Fe63.87Co9.13. Varying the intensities of the shots and the shot-to-shot separation, we reveal the conditions for ultrafast writing and the fastest possible restoration of magnetic bits. It is shown that although magnetic writing launched by the first shot is completed after 100 ps, a reliable rewriting of the bit by the second shot requires separating the shots by at least 300 ps. Using two shots partially overlapping in space and minimally separated by 300 ps, we demonstrate an approach for GHz magnetic writing that can be scaled down to sizes below the diffraction limit.

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Ultrafast Laser Cleaning of Daguerreotypes

MRS Proceedings ◽

10.1557/opl.2011.734 ◽

2011 ◽

Vol 1319 ◽

Cited By ~ 1

Author(s):

Michael J. Abere ◽

Ryan D. Murphy ◽

Bianca Jackson ◽

Gerard Mourou ◽

Michel Menu ◽

...

Keyword(s):

Material Removal ◽

Silver Oxide ◽

Laser Pulses ◽

Silver Sulfide ◽

Ultrafast Laser ◽

Beam Diameter ◽

Chemical Cleaning ◽

Silver Substrate ◽

Fs Laser ◽

Lower Material

ABSTRACTAn ultrafast laser irradiation method for the removal of corrosion from Daguerreotypes without detrimentally affecting image quality has been developed. Corrosion products such as silver oxide and silver sulfide may be removed by chemical cleaning but these reactions are hard to control and are often damaging to the underlying silver, ruining the image. The Ti:Sapphire 150 fs laser pulses used in this study are focused to a beam diameter of 60 μm and are normally incident to the Daguerreotype. It was found that the corrosion layer has a lower material removal threshold than silver allowing for removal of corrosion with minimal removal of vital information contained in the silver substrate.

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Fabrication and Characterization of Si Nano-Columns by Femtosecond Laser

Journal of Nano Research ◽

10.4028/www.scientific.net/jnanor.16.15 ◽

2012 ◽

Vol 16 ◽

pp. 15-20 ◽

Cited By ~ 4

Author(s):

Omid Tayefeh Ghalehbeygi ◽

Vural Kara ◽

Levent Trabzon ◽

Selcuk Akturk ◽

Huseyin Kizil

Keyword(s):

Laser Ablation ◽

Femtosecond Laser ◽

Laser Beam ◽

Chemical Etching ◽

Silicon Surface ◽

Laser Pulses ◽

Laser Beam Profile ◽

Fs Laser ◽

Fabrication And Characterization

We fabricated Si Nano-columns by a femtosecond laser with various wavelengths and process parameters, whilst the specimen was submerged in water. The experiments were carried out by three types of wavelengths i.e. 1030 nm, 515nm, 343nm, with 500 fs laser pulses. The scales of these spikes are much smaller than micro spikes that are constructed by laser irradiation of silicon surface in vacuum or gases like SF6, Cl2. The Si nano-columns of 300 nm or less in width were characterized by SEM measurements. The formation of these Si Nano-columns that were revealed by SEM observation, indicates chemical etching with laser ablation occurred when surface exposed by laser beam. We observed 200 nm spikes height at the center of laser beam profile and the ones uniform in height at lateral incident area.

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Competition Effects during Femtosecond Laser Induced Element Redistribution in Ba- and La-Migration Based Laser Written Waveguides

Materials ◽

10.3390/ma14123185 ◽

2021 ◽

Vol 14 (12) ◽

pp. 3185

Author(s):

Manuel Macias-Montero ◽

Pedro Moreno-Zárate ◽

Francisco Muñoz ◽

Belén Sotillo ◽

Marina Garcia-Pardo ◽

...

Keyword(s):

Laser Processing ◽

Optical Waveguides ◽

Phosphate Glasses ◽

Competition Effect ◽

Competition Effects ◽

Fs Laser ◽

Index Contrast ◽

The Cross ◽

Element Redistribution ◽

Element Migration

Fs-laser induced element redistribution (FLIER) has been a subject of intensive research in recent years. Its application to various types of glasses has already resulted in the production of efficient optical waveguides, tappers, amplifiers and lasers. Most of the work reported on FLIER-based waveguides refers to structures produced by the cross-migration of alkali (Na, K) and lanthanides (mostly La). The latter elements act as refractive index carrying elements. Herein, we report the production of Ba-based, FLIER-waveguides in phosphate glass with an index contrast > 10−2. Phosphate glasses modified with the same amount of Na2O and K2O, and variable amounts of BaO and/or La2O3 were used to produce the FLIER-waveguides with Ba and or La acting as index carriers. Ba-only modified glasses show a waveguide writing threshold and light guiding performance comparable to that of La-based structures. However, mixed Ba-La glasses show a much higher element migration threshold, and much smaller compositionally modified regions. This behavior is consistent with a competition effect in the cross-migration of both elements (Ba and La) against the alkalis. Such an effect can be applied to inhibit undesired element redistribution effects in fs-laser processing applications in multicomponent glasses.

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