Laser-driven plasmonic gratings for hiding multiple images

Abstract

Encoding diffractive images using smart laser printing for applications in security, design and data storage.

Local Annealing of Ag-TiO2 Nanocomposite Films with Plasmonic Response by CW UV Laser Scanning

“…As a result of exposure to laser irradiation, the surface of the material changes. Laser annealing causes compaction of Ag-TiO2 films, which reduces its thickness by 10-20% compared to the thickness of the original film [4,7], that indicates structural changes in the matrix. Thus, local modification occurs not only due to the formation of NPs, but also due to a change in the structure of the film.…”

“…In the last decade, nanocomposite materials based on such transparent matrices as TiO2, ZnO, Al doped ZnO with noble nanoparticles (NPs) have become particularly attractive in the emerging fields of photonics [1], catalysis [2,3], and security applications [4]. These materials have unique spectral characteristics because of surface plasmon resonance that have an influence on them.…”

Anti‐Counterfeiting White Light Printed Image Multiplexing by Fast Nanosecond Laser Processing

“…In last years, femtosecond laser processing of similar films was largely investigated, demonstrating the growth and reshaping of silver nanoparticles, their self-organization along embedded or surface gratings, as well as three dimensional self-organization. [40,41,45] However, for industrial applications, femtosecond lasers appear to be very expensive, and this led us to consider processing by nanosecond lasers already largely used for personalized grey level marking in the security market. The results reported below are the first ones demonstrating nanosecond-laser-induced self-organization of silver nanoparticles in TiO2 thin films.…”

Tailoring metal-dielectric nanocomposite materials with ultrashort laser pulses for dichroic color control

“…This structure is similar to one of the structures reported in our former work 14 obtained at this speed and belongs to the class of laser-induced periodic surface structures (LIPSS). [15][16][17][18][19][20][21] LIPSS can be formed when a material is exposed to multiple short or ultrashort laser pulses at energies above the modification threshold. 15,[22][23][24] The underlying mechanism of this self-organization process is attributed to the interference of the incident laser light with a surface wave, which leads to a periodic intensity modulation that is imprinted into the material.…”

“…The refractive index of the glass is 1.5171 and density 2.479. The films were elaborated on these substrates by sol-gel process consisting of titanium tetraisopropoxide (TTIP, Aldrich; 97%), acetylacetone (AcAc, Aldrich; 99%), hydrochloric acid (HCl, Roth; 37%), ethanol (EtOH, Carlo Erba; absolute), Pluronic P123 ((PEO) 20 (PPO) 70 (PEO) 20 (Aldrich; MW: 5000), and ultrapure water (H 2 O) with specific molar ratios at: TTIP : P123 : EtOH : HCl : H 2 O : AcAc :: 1 : 0.025 : 28.5 : 0.015 : 29.97 : 0.5, as published previously in our articles. 48 The films were annealed at 340°C, to obtain mesoporous amorphous titania thin films with a thickness of 200 ± 30 nm.…”