Alex Rozhin

• Lecturer at Aston University

Micro- and nanoplastics (MNPs) pose a significant threat to marine and human life due to their immense toxicity. To protect these ecosystems, the development of reliable technologies for MNP detection, characterisation, and removal is vital. While FTIR and Raman spectroscopy are established methods for MNP analysis, fluorescence (FL) spectroscopy h...

Homogeneous dispersion of plant food pigments is indispensable to study their characteristic fluorescence features for non-destructive rapid monitoring of food systems. However, it is highly challenging to obtain such optical grade homogenized stable dispersion of various plant pigments in aqueous media for tracing their precise fluorescence signat...

Bidirectional wavelength-tunable mode-locked fiber lasers have demands for many applications. In our experiment, two frequency combs from a single bidirectional carbon nanotube mode-locked erbium-doped fiber laser are obtained. Continuous wavelength tuning is demonstrated in the bidirectional ultrafast erbium-doped fiber laser for the first time. W...

3D organic‐inorganic metal halide perovskites are excellent materials for optoelectronic applications due to their exceptional properties, solution processability, and cost‐effectiveness. However, the lack of environmental stability highly restricts them from practical applications. Herein, a stable centimeter‐long 2D hybrid perovskite (N‐MPDA)[PbB...

Semiconductor quantum dots of the A2B6 group and organic semiconductors have been widely studied and applied in optoelectronics. This study aims to combine CdTe quantum dots and perylene-based dye molecules into advanced nanostructure system targeting to improve their functional properties. In such systems, new electronic states, a mixture of Wanni...

We have compared the wavelength tuning capability of filter-controlled fiber laser with cavity loss-controlled fiber laser when they emit dissipative soliton in L band. Two types of typical tunable filters (birefringence filter and fiber taper filter) and variable attenuators (a taper-type attenuator and commercial mechanical attenuator) are select...

Two-dimensional organic–inorganic hybrid perovskites are much attracted due to promising stable optoelectronic properties with tunable quantum well structures. Herein, we report the photodetector performance of the structurally tuned FA-incorporated hybrid perovskite FA-(N-MPDA)PbBr4 (FA = formamidinium and N-MPDA = N¹-methylpropane-1,3-diammonium)...

Carbon nanotube (CNT)–polymer composite films are key elements in widespread photonic and optoelectronic applications. One particular successful application is to produce ultrashort optical pulses in the laser cavity. Nevertheless, such composite film may suffer from severe humidity/water degradation, from which the laser may even stop generating r...

Solution‐processable 2D metal‐halide perovskites are highly promising for cost‐effective optoelectronic applications due to their intrinsic multiquantum well structure. However, the lack of stability is still a major obstacle in the use of this class of materials in practical devices. Here, the authors demonstrate the stable optoelectronic properti...

This paper presents the study of the photoluminescent properties of molecular compositions consisting of melanin and an electron-acceptor material – fullerene derivative, [6,6]-phenyl C61 butyric acid methyl ester (PCBM). These molecular compositions have not been studied well and are promising for molecular electronics of natural materials, in par...

We report on the first experimental observation of breathing solitons in a passively harmonic mode-locked fibre laser. Various features of a 4 th -harmonic operation state showing breather oscillations with a period of 5 roundtrips are discussed.

an innovative application of deep barrier silicon structures for sensory devices with photoelectrical transformation has been suggested. The principal possibility of the photovoltaic transducer implementation for identification of metallic and semiconductor single-wall carbon nanotubes covered with surfactant in water solution was analyzed in detai...

Two-dimensional (2D) materials have attracted significant attention in recent years owing to their exotic properties. Semiconducting p-type 2D crystals are crucial to the construction of versatile p-n junction-based nanoelectronic devices, and promising future optoelectronic applications. Herein, we reported the growth of high-quality p-type silico...

We demonstrate an L-band wavelength-tunable passively mode-locked fiber laser using a single long-period fiber grating (LPFG) as a narrow-band optical attenuator (NBOA). Through bending the LPFG, the central wavelength can be continuously tuned from 1582.02 to 1597.29 nm, while the output power only varies from 1.465 to 1.057 mW, approximately a ra...

Single-walled carbon nanotubes (SWCNTs) are widely explored for the ultrashort pulse generation in the fiber lasers enabled by pronounced saturable absorption (SA) effect. Despite many remarkable results demonstrated in the area, degradation of the samples inside the laser cavity limits the widespread use of SWCNT-SA. In the present work, we invest...

The kinetics of photoluminescence (PL) and time-resolved emission spectra (TRES) of melanin solutions with an effective electron acceptor 2,4,7-trinitrofluorenone (TNF) have been studied. Based on the analysis of the kinetic decay curves and TRES, the fast and slow PL decay components can be distinguished, which characterize the processes of a rela...

In this work, we examined the nature and pathways of electronic excitation relaxation at low temperature in cationic pentamethine pyrylocyanine dye, which in the ground state is characterized by symmetric and non-symmetric localization of cationic charge on the carbon chain between the terminal groups. The carbon chain in such symmetric and non-sym...

We examine the implication of intracavity nonlinearity for harmonic mode locking (HML) by exploiting highly nonlinear fiber in a carbon nanotube film mode-locked Er-doped fiber laser. It is found that the reasonably large nonlinearity is of benefit to increase the extent of harmonic order while the excessive nonlinearity leads to some peculiar mult...

We demonstrate a nonlinearity managed passively harmonic mode-locked Er-doped fiber laser using carbon nanotubes film. Lowering the pulse energy via careful nonlinearity management results in 3.4GHz pulse generation with only 250mW pump power.

Carbon nanotubes (CNTs) possess remarkable nonlinear optical properties; a particular application is to function as a mode locker used in ultrafast fiber lasers to produce ultrashort optical pulses. Various types of CNT saturable absorbers (SAs) and ultrafast fiber lasers have been demonstrated. In this review, typical fabrication process and devel...

Interest in gas sensing using functionalised carbon nanotubes is a major area of research that utilises changes in their electrical properties induced by the reaction with a specific gas. This paper describes specific gas sensing on an optical platform consisting of a 2-dimensional nano-structured plasmonic array of nano-antennae/nanowires, with to...

Three-dimensional organic-inorganic hybrid halide perovskites have been demonstrated as a great material for applications in optoelectronics and photonics. However, their inherent instabilities over moisture, light, and heat may hinder their road towards the realization of commercialization. Alternatively, emerging two-dimensional (2D) organic-inor...

We report experimental observation of polarization attractors in the form of vector dissipative solitons from a carbon nanotube mode locked fiber laser. At a time scale of 14–14,000 roundtrips, the typical polarization locked vector solitons, and other appealing attractors are shown. In addition, we observe the vector dissipative solitons operated...

We demonstrated a continuously wavelength-tunable bidirectional passively $ Q $ -switched fiber laser based on a single-walled carbon nanotube saturable absorber and a bandpass filter (BPF). By tuning the commercial BPF, the $ Q $ -switched pulse can be obtained in the same cavity at the same pump power in clockwise (CW) and counter-clockwise (CCW)...

Time resolved emission spectra (TRES), 3D maps of photoluminescence excitation-emission (PLE maps), 3D maps of TRES, and kinetics of photoluminescence (PL) spectra of natural and synthetic melanin, as well as melanin composites with surfactant, sodium dodecyl benzenesulfonate, have been studied. The kinetics of PL and TRES for the melanin and the c...

We have demonstrated a bidirectional wavelength-tunable mode-locked fiber laser. The wavelength can be continuously tuned from 1567.3 to 1561.21 nm in the clockwise direction and from 1567.25 to 1561.19 nm in the counter-clockwise direction.

In this paper, a dissipative soliton mode-locked fiber laser is established based on carbon nanotube in order to study the polarization dynamics of dissipative soliton by using a commercial polarimeter. Under the pump power of 160 mW, stable dissipatives soliton are observed to have a limited cycle polarization trajectory shown on Poincare sphere,...

We experimentally demonstrate a passively harmonic mode locked (PHML) Er-doped fiber laser with pump power efficiency up to 17 MHz/mW operating at L-band based on single walled carbon nanotubes polyvinyl alcohol (SWCNTs-PVA) film. Under 233 mW pump power, the stable pulse train at 1594.97 nm with 40.5 dB side mode suppression ratio (SMSR) and 742 f...

A controllable passive harmonic mode locking (HML) in an erbium-doped fiber laser with a soliton pulse shaping using a single-wall carbon nanotube has been experimentally demonstrated. By increasing the pump power and adjusting the in-cavity polarization controller, we reached the 51st-order harmonic (902 MHz) having the output power of 37 mW. We a...

Detection of ammonia by carbon nanotubes is an extensively studied area where tremendous progress was achieved so far in their sensing performance. In this paper, we focused on carbon nanotube network sensors of NH 3 aiming to develop better understanding of their gas detection behavior and improved sensing response. Our experiments showed improved...

Detection of ammonia by carbon nanotubes is an extensively studied area where tremendous progress was achieved so far in their sensing performance. In this paper, we focused on carbon nanotube network sensors of NH 3 aiming to develop better understanding of their gas detection behavior and improved sensing response. Our experiments showed improved...

Development of novel nanoscale devices requires unique functional nanomaterials. Furthermore, chemical design of different nanoparticles in one unit is a complex task, particularly the application of self-assembly J-aggregates, which can substantially advance the nanomaterial’s properties due to resonant delocalization of excitons. Here, we have de...

We systematically study the impact of average cavity dispersion and pulse spectral bandwidth on harmonic mode locking in the long-wavelength band from an Er-doped fiber laser using carbon nanotubes polyvinyl alcohol (CNTs-PVA) film mode locker. By carrying out pulse energy management through optimizing the average cavity dispersion and optical spec...

We present a passively mode-locked Erbium-doped fiber laser with tunable parameters including central wavelength, 3dB bandwidth and pulse duration. The mode-locking mechanism of the laser is realized by using single-walled carbon nanotubes polyvinyl alcohol (SWCNTs-PVA) composite film as saturable absorber. The tunable operation is implemented via...

We identified different nano-carbon species such as graphene nanoplatelets, graphite flakes and carbon nanotubes dispersed in N-methyl-2-pyrrolidone using a novel sensor structure based on a "deep" silicon barrier working as a photoelectrical transducer. Each nano-carbon particle has specific signature in both 2D photocurrent distribution and photo...

Soliton rain is a bunch of small soliton pulses accompanying the main pulse with the period of a round trip. It was found previously that soliton-soliton interaction through the overlapping of their tails or soliton-dispersive wave interaction can result in spikes with an anomalous amplitude satisfying the rogue waves (RW) criteria. Here, we report...

We have demonstrated an all-fiber passively mode locked erbium-doped fiber laser (EDFL) based on graphene-polyvinyl-alcohol film. By watchfully adjusting the polarization controller, two different polarization attractors, including polarization locked vector solitons and a circular attractor, can be observed. This is first time, to the best of our...

We have experimentally investigated the polarization dynamics of an all-fiber passively mode-locked laser based on graphene using polarimeter for the first time. By carefully adjusting polarization controllers, two types of polarization attractors are obtained.

We identified different nano-carbon species such as graphene nanoplatelets, graphite flakes and carbon nanotubes dispersed in N-methyl-2-pyrrolidone using a novel sensor structure based on a “deep” silicon barrier working as a photoelectrical transducer. Each nano-carbon particle has specific signature in both 2D photocurrent distribution and photo...

A single/dual-wavelength switchable bidirectional -switched fiber laser using a bidirectional fiber polarizer is demonstrated. A 45° tilted fiber grating is used as a bidirectional fiber polarizer to induce a bidirectional intracavity birefringence filter in both clockwise (CW) and counter-clockwise (CCW) directions. A carbon nanotube saturable abs...

Spectral properties of the series of cationic polymethine dyes containing conjugated chain of different length and 4-pyrylium terminal groups were studied in details. Besides, the steady-state long-wavelength fluorescence from the lowest excited state and the fluorescence from higher excited states were experimentally revealed. The steady-state flu...

We demonstrate a passively harmonic mode-locked (PHML) fiber laser operating at the L-band using carbon nanotubes polyvinyl alcohol (CNTs-PVA) film. Under suitable pump power and an appropriate setting of the polarization controller (PC), the 54th harmonic pulses at the L-band are generated with the side mode suppression ratio (SMSR) better than 44...

Steady-state and time-resolved photoluminescence (PL) spectra of natural and synthetic melanin, as well as melanin composites with surfactant, sodium dodecylbenzenesulfonate, and polymethine dye, astraphloxin, have been studied. The melanin molecules having differently charged peripheral groups with terminal O atoms and OH groups mixed with the neg...

Composites of single-walled carbon nanotubes (SWNTs) and water-soluble polymers (WSP) are the focus of significant worldwide research due to a number of applications in biotechnology and photonics, particularly for ultrashort pulse generation. Despite the unique possibility of constructing non-linear optical SWNT-WSP composites with controlled opti...

During the last two decades, revealing mechanisms of origin waves with anomalous amplitude (rogue waves) have been in the focus of researchers from different fields ranging from oceanography to laser physics. Mode‐locked lasers, as a test bed system, provide a unique opportunity to collect more data on rogue waves in the form of random pulses (soli...

We propose and demonstrate a passively harmonic mode-locked erbium-doped fiber laser (EDFL) using carbon nanotubes polyvinyl alcohol (CNTs-PVA) film. The laser allows generation of the pulses with a repetition rate of 580 MHz, which corresponds to the 22nd harmonics of a 26.3 MHz fundamental repetition rate under 323 mW pump power. A particularly n...

We have demonstrated a passively harmonic mode-locked Er-doped fiber laser operating at L band based on carbon nanotubes film. 456.76 MHz pulses at 49th harmonics centered at 1595.98nm with 45dB super-mode suppression ratio can be realized.

A wavelength switchable bidirectional Q-switched fiber laser based on carbon nanotube saturable absorber and 45° tilted fiber grating induced nonlinear polarization rotating filtering effect is demonstrated for the first time.

A carbon nanotube mode-locked fiber laser based on an all-fiber birefringent filter consisting of 45° tilted fiber grating and polarization maintaining fiber is demonstrated with a 30 nm tuning range.

We demonstrate a wavelength tunable bidirectional Q-switched fiber laser based on carbon nanotube and a tunable bandpass filter with tuning range 51.43nm from 1515.43nm to 1566.86nm in clockwise and counter-clockwise direction for the first time.

Passively harmonic mode locking in a fiber laser based on single wall carbon nanotubes polyvinyl alcohol film is experimentally implemented. 916MHz pulses at the 34th harmonic with 41dB super-mode suppression ratio can be generated.

In the present study, we demonstrate efficient detection of volatile organic vapors with improved sensitivity, exploiting the localized surface plasmon resonance of indium nanograins in the UV range (UV-LSPR). The sensitivity of deep-UV-LSPR measurements toward ethanol was observed to be 0.004 nm/ppm, which is 10 times higher than that of a previou...

With the progression towards personalised and age-appropriate medicines, the production of drug loaded liposomes at the point of care would be highly desirable. In particular, liposomal solubilisation agents that can be produced rapidly and easily would provide a new option in personalised medicines. Such a process could also be used as a rapid too...

The emergence of low-dimensional materials has opened new opportunities in the fabrication of compact nonlinear photonic devices. Single-walled carbon nanotubes were among the first of those materials to attract the attention of the photonics community owing to their high third order susceptibility, broadband operation, and ultrafast response. Satu...

Novel applications of organic dyes and vast opportunities for their molecular tailoring keep focus of scientific community on the issues of symmetry breaking in the systems having different location of uncompensated charge, which has tremendous impact on photoluminescent properties of the dyes. In this paper, we provide distinctive experimental evi...

A possibility to obtain graphene and graphene layers with the help of the ultrasound (US) treatment of pyrolytic graphite in an N-methyl pyrrolidone (NMP) solution has been demonstrated. Raman spectroscopy is confirmed to be an effective method for monitoring the graphite transformation into graphene. By varying the time of the ultrasonic treatment...

A wavelength-tunable all-fiber Erbium-doped mode-locked fiber laser based on carbon nanotubes and 45° tilted fiber grating (TFG) is demonstrated. We investigated the effect of PDL of 45TFG in the tuning range of a mode locked laser. The central wavelength of the laser can be tuned continuously from 1559.85 nm to 1564.46 nm with a tuning range of 4....

The complex nonlinear dynamics of mode-locked fibre lasers, including a broad variety of dissipative structures and self-organization effects, have drawn significant research interest. Around the 2 μm band, conventional saturable absorbers (SAs) possess small modulation depth and slow relaxation time and, therefore, are incapable of ensuring comple...

Enzyme-functionalized thin-cladding long-period fiber grating in transition mode at dispersion turning point for sugar-level and glucose detection, " J. Abstract. Enzyme-functionalized dual-peak long-period fiber grating (LPFG) inscribed in 80-μm-cladding B/Ge codoped single-mode fiber is presented for sugar-level and specific glucose detection. Be...

We have demonstrated an all-fiber erbium laser incorporating a few-mode fiber long-period grating passively Q-switched by carbon nanotube for cylindrical vector beam generation. The laser can output both radially and azimuthally polarized beams.

We will discuss the development of nano-inks based on carbon nanotubes and methods of their integration into optical fibers. The hybrid nano-photonic devices allow to obtain lasers, gas and refractive Index sensors with improved characteristics.

The possibility of using the principle of photoelectric conversion in structures with a deep p-n junction to control the content of carbon nanotubes with adsorbed surfactant (SDBS) in an aqueous solution was shown. Experimental studies of the analyte influence on the change in the photocurrent through a deep p-n junction were carried out. A shift i...

Passively harmonic mode-locking (HML) of an Erbium-doped fiber laser using carbon nanotubes polyvinyl alcohol (CNTs-PVA) film is presented. The 20th harmonic mode-locking pulses at 500MHz repetition rate with 42dB super-mode suppression ratio (SMSR) are achieved.

We fabricated three SWCNT-PVA composite films containing more metallic carbon nanotubes by CoMoCAT for the first time and influence of these composite films on performance of an Erbium-doped mode locked fiber laser is also studied.

The unique properties of carbon nanotubes have made them the material of choice for many current and future industrial applications. As a consequence of the increasing development of nanotechnology, carbon nanotubes show potential threat to health and environment. Therefore, development of efficient method for detection of carbon nanotubes is requi...

Additional figures and discussion.

Zinc-air fuel cells (ZAFCs) present a promising energy source with a competing potential with the lithium-ion battery and even with proton-exchange membrane fuel cells (PEMFCs) for applications in next generation electrified transport and energy storage. The regeneration of zinc is essential for developing the next-generation, i.e., electrochemical...

Zinc-air fuel cells (ZAFCs) present a promising energy source with a competing potential with the lithium-ion battery and even with proton-exchange membrane fuel cells (PEMFCs) for applications in next generation electrified transport and energy storage. The regeneration of zinc is essential for developing the next-generation, i.e., electrochemical...

Nano-diamond (ND) is material having unique surface, thermal and optical properties promising for application in high-power electronics, pharmacy, etc. In this report, we develop a nano-diamond ink, which can be printed in micro array applicable for anti-microbial and bio-sensor applications. Firstly, nano-diamond was synthesized via laser ablation...

Self-organization of organic molecules with carbon nanomaterials leads to the formation of functionalized molecular nanocomplexes with advanced features. We present a study of physical and chemical properties of carbon nanotube-surfactant-indocarbocyanine dye (astraphloxin) in water focusing on aggregation of the dye and resonant energy transfer fr...

ZnO nanomaterials with controlled size, shape and surface chemistry are required for applications in diverse areas, such as optoelectronics, photocatalysis, biomedicine and so on. Here, we report on ZnO nanostructures with rod-like and spherical shapes prepared via laser ablation in liquid using a laser with millisecond-long pulses. By changing las...

An Erbium-doped fibre ring laser hybrid mode-locked with single-wall carbon nanotubes (SWNT) and nonlinear polarisation evolution (NPE) without an optical isolator has been investigated for various cavity conditions. Precise control of the state of polarisation (SOP) in the cavity ensures different losses for counter-propagating optical fields. As...

Carbon nanotubes (CNTs) possess both remarkable optical properties and high potential for integration in various photonic devices. We overview, here, recent progress in CNT applications in fibre optics putting particular emphasis on fibre lasers. We discuss fabrication and characterisation of different CNTs, development of CNT-based saturable absor...

This paper presents a highly sensitive ambient refractive index (RI) sensor based on 81° tilted fiber grating (81°-TFG) structure UV-inscribed in standard telecom fiber (62.5μm cladding radius) with carbon nanotube (CNT) overlay deposition. The sensing mechanism is based on the ability of CNT to induce change in transmitted optical power and the hi...