Roman Zakoldaev

UiT The Arctic University of Norway · Department of Physics and Technology

Stable polychrome marking on glass products is a highly demanded operation in industry. In this work indirect laser processing for polychrome marking of glass in the acceptor–donor (back laser-induced film transfer) scheme is demonstrated for the first time. The glass color marking was performed by a widespread industrial laser marker in conjunctio...

Chiral plasmonic nanostructures have emerged as promising objects for numerous applications in nanophotonics, optoelectronics, biosensing, chemistry, and pharmacy. Here, we propose a novel method to induce strong chirality in achiral ensembles of gold nanoparticles via irradiation with circularly-polarized light of a picosecond Nd:YAG laser. Embedd...

This study examines the effects of alkaline etching on laser-induced modifications within a mesoporous silicate matrix, specifically focusing on birefringent structures, densification, and decompaction. Femtosecond direct laser writing is employed to create these modifications, which are then subjected to alkaline etching with potassium hydroxide t...

Hybrid integration of photonic chips with electronic and micromechanical circuits is projected to bring about miniature, but still highly accurate and reliable, laser spectroscopic sensors for both climate research and industrial applications. However, the sensitivity of chip-scale devices has been limited by immature and lossy photonic waveguides,...

Barriers were produced in porous glass through its local bulk density modification by direct femtosecond writing accompanied by СО2-laser surface thermal densification, to make functional microfluidic elements separated by such physical barriers with different controlled permeability. The separation of multi-component solutions into individual comp...

Spectroscopic detection of gases and their stable isotopes holds significant value in bio-sciences and climate studies. However, achieving high precision has long been confined to bulky and costly equipment. In this work, we introduce a nanophotonic waveguide that is capable of detecting CO₂ gas down to 20 parts per billion, and for the first time...

Spectroscopic detection of gases and their stable isotopes holds significant value in bio-sciences and climate studies. However, achieving high precision has long been confined to bulky and costly equipment. In this work, we introduce a nanophotonic waveguide that is capable of detecting CO₂ gas down to 20 parts per billion, and for the first time...

Microfluidic systems have become part of our everyday life, with surface microfluidics occupying its niche in instant diagnostics and point-of-care testing. Implementing surface microfluidics on a large scale appears to be impossible without developing or upgrading manufacturing technologies. Our paper proposes a CO2-laser microtechnology of precis...

Spiral phase plates are a common method, which provides direct efficient generation of beams carried orbital angular momentum from Gaussian beams. They are characterized by high efficiency and less complex structure compared to other optical elements used for vortex beams generation. In this paper, we propose to use laser-induced microplasma (a sim...

Femtosecond direct laser writing (FDLW) is a powerful tool for modification of the properties of transparent materials through nonlinear multiphoton absorption. Implementing such a tool makes it possible to fabricate buried optofluidic elements for microfluidic (MF) systems and optical waveguides in glass materials. In this study a novel method for...

We present the results of direct laser writing of birefringent structures array in a nanoporous silicate matrix (NPSM) with average pore size of 17 nm and porosity 50 %. The characteristics of retardance and transmission for one layer of recorded elements are investigated. The necessary parameters for fabrication of a phase plate based on birefring...

The writing process of birefringent structures in the volume of fused silica by focused ultrashort laser pulses with wavelength in visible range and various values of pulse energy, pulse duration, repetition rate, numerical aperture and moving substrate velocity has been studied. The retardance value of fabricated structures has been measured and i...

With the growth of laser technologies in photonics, the volume phase elements fabrication in transparent material by ultrashort laser is widely attractive. Femtosecond laser writing (FLW) step was applied for the polarized-sensitive volume phase gratings (VPGs) inscription in the nanoporous silicate matrix (NPSM). The formed VPGs with thickness L =...

The inscription regimes and formation mechanisms of form-birefringent microstructures inside nano-porous fused silica by tightly focused 1030- and 515-nm ultrashort laser pulses of variable energy levels and pulsewidths in the sub-filamentary regime were explored. Energy-dispersion X-ray micro-spectroscopy and 3D scanning confocal Raman micro-spect...

Plasmon resonance tuning was performed by femtosecond laser processing of silver-contained TiO2 sol-gel films. We consider the key role of utilized wavelengths - 343 nm and 515 nm, in terms of changing morphology, nanoparticles size and spectrum. The plasmon resonance peak of processed films exhibits an overall decrease (from 2.8 to 2.5 eV) with th...

Laser inscription of form-birefringent nanograting layers inside fused silica by ultrashort (femto-picosecond) laser pulses at 515 nm was studied as a function of laser, average power and pulsewidth in terms of fabrication regimes. Retardance magnitudes were acquired for single birefringent layers inscribed at different laser parameters, enabling f...

Исследовано взаимодействие фемтосекундных лазерных импульсов с поверхностью кварцевого стекла. В результате интерференции между падающим излучением и поверхностными плазмон-поляритонами наблюдалось образование самоорганизующихся субволновых периодических структур с периодом 250 nm. Выявлена минимальная энергия в импульсе, при которой запись происхо...

The paper demonstrates direct laser writing by femtosecond laser pulses (λ = 1030 nm, τ = 220 fs, v = 200 kHz) of functional optofluidic elements inside a nanoporous silicate matrix (NPSM). The influence of focused laser pulses led to the compaction of the nanoporous frame, which made it possible to fabricate barriers for the isolation of nanoporou...

The effect of the power and scanning speed of СО₂-laser radiation on the surface of fused silica for the manufacture of microchannels and microreservoirs for microfluidics tasks is investigated. The dependences of the size and roughness of microstructures on the parameters of laser radiation are established. The depth of microfluidic elements reach...

Предложен метод получения металлических плазмонных наноструктур с линейным дихроизмом, основанный на методе выжигания постоянных спектральных провалов. Изотропные гранулированные серебряные пленки, полученные физическим осаждением паров в вакууме, облучались линейно поляризованным лазерным излучением в спектральной области плазмонного резонанса сос...

The interaction of femtosecond laser pulses with the surface of silica glass has been studied. As a result of interference between the incident radiation and surface plasmon polaritons, the formation of self-organizing subwavelength periodic structures with a period of 250 nm was observed. The minimum pulse energy at which recording occurs without...

The paper demonstrates direct laser writing by femtosecond laser pulses (λ = 1030 nm, tau = 220 fs, v = 200 kHz) of functional optofluidic elements inside a nanoporous silicate matrix (NPSM). The influence of focused laser pulses led to the compaction of the nanoporous frame, which made it possible to fabricate barriers for the isolation of nanopor...

A method for obtaining metallic plasmonic nanostructures with linear dichroism, based on the method of burning out constant spectral dips, is proposed. Isotropic granular silver films obtained by physical vapor deposition in vacuum were irradiated with linearly polarized laser radiation in the spectral region of the plasmon resonance of their const...

The paper discusses the action of the power and the scanning speed of CO 2 -laser radiation on the surface of fused silica for the manufacture of microchannels and microreservoirs for microfluidics tasks is investigated. The dependences of the size and the roughness of microstructures on of laser radiation parameters is established. The depth of mi...

Three-segment microtracks were for the first time inscribed in bulk fluorite in the scanning mode via multishot exposure by tightly-focused 515-nm ultrashort laser pulses of variable pulse energy and pulsewidth (0.3-3.8 ps). The local micro/nanoscale material modification and related refractive-index changes within the microstructures, envisioned b...

Periodic nanostructures with a period of about 100–150 nm are formed on the surface of nanoporous silicate glass irradiated by sharply-focused laser pulses with a wavelength of 515 nm and a duration of 300 fs and are visualized by scanning electron microscopy. The reflection/transmission spectroscopy of the formed nanostructures in the visible rang...

Фемтосекундное лазерное структурирование диэлектриков является актуальной задачей для создания оптических элементов. В данной работе выполнялось фемтосекундное лазерное наноструктурирование поверхности фторида кальция с образованием самоорганизующихся периодических решеток, которые обладают субволновым периодом порядка 200 и 350 nm. В процессе рабо...

На поверхности нанопористого силикатного стекла под действием остросфокусированного лазерного излучения с длиной волны 515 нм и длительностью 300 фс сформированы периодические наноструктуры с периодом ∼ 100–150 нм, визуализированные методом сканирующей электронной микроскопии. Спектроскопия отражения/пропускания полученных наноструктур в видимом ди...

Впервые в объеме пластины флюорита получены двулучепреломляющие микроструктуры, записанные на фиксированной глубине под действием лазерных импульсов с длиной волны 1030 нм, варьируемой длительностью 0.3–3.8 пс и энергией импульсов лазерного излучения. Для всех длительностей лазерных импульсов установлены монотонные восходящие зависимости фазового с...

Laser-induced structuring of nanoporous glass composites is promising for numerous emerging applications in photonics, plasmonics, and medicine. In these laser interactions, an interplay of photo-thermo-chemical mechanisms is commonly activated and is extremely difficult to control. The choice of optimum laser parameters to tune the resulted optica...

Controllable transparency level is the key parameter for production of the grayscale masks for the aims of submicron photolithography. In this work, we have developed an analytical model to predict transparency dependencies of the irradiated areas on thin titanium films during laser oxidative treatment. This allows controlling final optical propert...

Indirect laser-based surface nano- and microprocessing of optical materials demonstrate promising applications in microoptics, microfluidics and electrofluidic. The methods principle is based on the conversion of laser energy to a plasma plume, which effectively and precisely etch the glass backside. However, there are a lot of variable occurs duri...

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 standa...

Laser-induced thermochemical recording of nano- and microsized structures on thin films has attracted intense interest over the last few decades due to essential applications in the photonics industry. Nevertheless, the relationship between the laser parameters and the properties of the formed oxide structures, both geometrical and optical, is stil...

The action of ultrashort laser pulses on dielectrics leads to the processes of redistribution of the laser pulse energy in the interaction region. The mechanisms of ultrafast energy deposition and the electron dynamics under the action of ultrashort laser pulses determine the type of final structures or elements in the transparent dielectrics. One...

In this work, we suggest the new concept of sensing elements—bulk waveguides (BWGs) fabricated by the laser direct writing technique inside porous glass (PG). BWGs in nanoporous materials are promising to be applied in the photonics and sensors industries. Such light-guiding components interrogate the internal conditions of nanoporous materials and...

For sure, we believe in various applications of such waveguides in nanoporous matrix. Here is just one of a possible application. You are welcome for fruitful discussion.

Laser-induced structuring in nanoporous glass composites is promising for numerous emerging applications in photonics and plasmonics. Local laser irradiation activates an interplay of photo-thermo-chemical mechanisms that are extremely difficult to control. The choice of optimum laser parameters to fabricate structures with desired properties remai...

Poster from LPM'18

Photoelectrical and photoluminescent properties of multilayer graphene (MLG)–quantum dots (QD) hybrid structures have been studied. It has been shown that the average rate of transfer from QDs to the MLG can be estimated via photoinduced processes on the QDs’ surfaces. A monolayer of CdSe QDs can double the photoresponse amplitude of multilayer gra...

Spiral phase plate is the most commonly used optical element for generating an optical vortex beam. It is widely applied due to its higher efficiency and less complex structure compared to other optical elements used for this purpose. The paper presents a simple, reliable and high-performance technology for manufacturing of a spiral phase plate on...

In this work, a new domain of femtosecond laser-induced densification was exploited as a method for space-selective control of porous glass matrix density. The estimated refractive index change (Δn) of laser-induced modified region shows a core-cladding structure with the Δn in the range of 10−4–10−2 depending on laser pulse energy and translating...

Multiple ultra-short laser irradiation enabling direct writing of high aspect ratio barriers is used for structuring of nanoporous glass. Shape and morphology of laser-modified regions are examined, and high aspect ratio laser-induced material densification is founded. Experimental results are analyzed by modeling describing laser propagation, non-...

In this paper, we investigate the local oxidation of titanium thin films under the action of picosecond laser pulses. Periodical structures were recorded by the multi-beam interference scheme utilizing various numbers of laser beams, and the relationship between spatial resolution and the contrast of the structures was studied. The Raman spectra of...

We report on a new type of a random phase plate (RPP) that can be applied for effective homogenization of coherent laser beams. The RPP is fabricated on a uniaxial birefringent crystal, ensuring the absence of speckles within the processing plane due to two orthogonally polarized beamlets with π phase difference. High fabrication speed ∼ 2 mm²/s of...

We investigate laser treatment regimes suitable for the fabrication of the isolated cells in a porous silica glass and a solgel film. Three-dimensional structures are produced as a result of the porous glass densification induced by femtosecond laser pulses. We also demonstrate that CO2 laser can be used to form such structures in the solgel film d...

The experimental results are presented for a laser-induced modification of the structure of porous glass (PG) preliminarily doped with an aqueous nitric-acid solution of Bi(NO3)3. It is established that the laser-induced local stabilization of bismuth active centers (BACs) in the bulk of PG plates is possible, which is confirmed by the change in th...

The possibility of creating physical barriers with various degrees of permeability in porous glass (PG) plates by local variation in the density of the porous structure of the matrix is demonstrated. The compaction of PG in the volume is provided by exposure to femtosecond laser pulses, while the surface impermeability of the compaction areas is pr...

Recent research in the field of formation of a 3D profile of optical elements with the use of direct laser writing at various wavelengths and photolithographic technologies on the basis of photomasks fabricated by means of laser writing is reviewed. Typical characteristics of the relief, as well as advantages and drawbacks of the above-mentioned me...

We report control possibilities over ultrafast laser-induced periodic void lines in porous glass. Instead of high intensity regime leading to filaments, multi-pulse irradiation with high repetition rate (500 kHz) and various writing speed is used here in a transverse geometry. The formation of a perfectly controlled periodic void structure is shown...

Local spatial and temporal control of laser-induced microplasma (LIMP) allows to form a mi-crorelief on fused silica plates for the fabrication of multilevel phase elements. In this work we sug-gested the optimal way for precision depth variation (up to 50 nm) of the microrelief (0.05 - 15 μm) on fused silica surface. New software and hardware were...

We have studied the properties of laser-induced microplasma (LIMP) emerging in the ablation of a strongly light-absorbing target in the regime of confinement of spatial plasma expansion. The LIMP particle temperature is shown to be higher in this case than in the free expansion. It is found that the amplitude of the pressure pulse in the regime of...

The structure modification in the bulk of plates of photochromic porous glass (PCPG) containing 0.28 wt % Ag2O under the action of laser irradiation of a near IR-range with a power density of 0.6–1.9 MW/cm² and irradiation duration of 5–20 s is carried out. Locally modified structure regions are composed of the central and edge parts with a differe...

This paper presents the results of studies of changes in the transmittance and luminescence spectra of quartz-glass plates caused by surface-processing the plates with laser-induced microplasma. The recorded changes are probably caused by a change in the surface roughness and by the microgeometry of the resulting relief, as well as by possible pene...

Interference of laser beams with high pulse energy opens an opportunity of direct oxidation of surfaces over large areas. It is important to confirm that the single ultrashort laser pulse irradiation is able to create the protective oxide layer on chromium films. Here, we report an approach of hybrid thermo-chemical treatment of thin chromium films...

The laser oxidation of thin metallic films followed by its selective chemical etching is a promising method for the formation of binary metal structures on the glass substrates. It is important to confirm that even a single ultrashort laser pulse irradiation is able to create the protective oxide layer that makes possible to imprint the thermochemi...

Structural changes and phase transformations of the photostructurable glass (PhG) surfaces under the impact of 10.6-μm wavelength laser radiation are examined. The regimes initiating the formation and development of crystalline phase and its reversible (secondary) amorphization are determined. In addition, the kinetic of crystalline phase formation...

A new technology for microlens array fabrication is presented. The technology is based on creation of the initial microstructures on fused silica by laser indirect method, and the following reflow process of these structures made by CO2 laser action. Microlens arrays with diameter of microlens equal to 150 µm are fabricated. The focal length of mic...

Method of 3D processing of photosensitive glass (PhG) is demonstrated and researched in this work. Structural changes and phase transformation are initiated by CO2 laser radiation on defects, which were pre-generated in the bulk of the PhG by powerful picosecond Nd:YAG laser second harmonic pulses. Reversible phase transformations were realized ins...

In this paper, we present the method of microlens arrays formation on the fused silica surfaces by the irradiation of ytterbium fiber laser (λ = 1.064 μm, τ ~ 100 ns, ν 10–100 kHz). MLAs formation time, depending on its size and the number of microlenses, ranged between 5 and 15 min. Microlenses with diameters of 150–400 μm were successfully formed...

Unusually high densification ≤26% was obtained without lateral residual stresses within the laser beam waist inside porous glass during its multi-shot femtosecond laser irradiation, which may induce in the glass the related high refractive index change ~0.1. Corresponding laser irradiation regimes, resulting in such ultra-densification, decompactio...

A technology of microrelief formation on the fused silica glass surface by laser induced black body heating is considered. An ytterbium fiber laser and a pressed graphite as an absorbent of laser radiation are used in this technology. The depth of the formed relief depending on the laser interact parameters has been investigated. It is shown that t...

The glass surface microstructuring technology using laser radiation with NIR wavelength (λ=1.064 μm) was revealed in this work. Glass plates were placed on the cellular graphite surface. Focused laser radiation passed through the glass plate and interacted with cellular graphite. The radiation heated the graphite surface and thus the high temperatu...

A technique for forming thermally densified layers on opposite wafer surfaces so as to retain a complex well-developed structure of porous glass wafers is proposed. These thermally densified layers passivate and protect porous glass from chemical degradation and aging. The process involves the formation of thermally densified layers and removal of...

The technique for laser-assisted modification of glass surface is suggested. The method is based on the heating of glass by graphite plate irradiated by laser being in direct contact with the glass surface from the backside. Transparency of glass and strong absorption of graphite for an incident laser radiation provide the diversity of applicable l...

An attempt at local modification of the optical properties in the interior of macroporous glass plates with po-rosity 0.58 cm 3 /cm 3 and average channel size 50 – 70 nm by means of laser radiation weakly absorbed in the material is reported. The source of radiation is an ytterbium fiber laser with radiation wavelength l = 1.07 mm, pulse duration t...

The focal length and numerical aperture of a complexly structured modified region in a plate of porous glass are determined. It is shown that when a plate of porous glass with a modified region is baked the complex structure of the modified region remains. The focal length and numerical aperture of the complexly structure modified region in the qua...

In this report we have presented the results of forming waveguide structures in the bulk of porous glass (PG) plates soddened with water solutions of different concentrations of glycerol — substance with high polarizability under the laser irradiation of wavelength low absorbed by plate material. Chemical composition of the plate used in experiment...