Maciej Czajkowski

• Doctor of Philosophy
• Senior Resarch Engineer at Lukasiewicz Research Network – PORT Polish Center for Technology Development

Sol–gel materials based on SiO2 and TiO2 precursors are attractive as a new platform for planar photonics. Particularly interesting are those based on organically modified silica (ORMOSIL), which may improve the luminescent properties of organic dyes. However, their microstructurization remains a challenge as it requires optimization of various tec...

Novel temperature sensors with unique optical properties, based on 4-alkylbenzoic acid developers (CnBA, where n is the number of carbon atoms in the alkyl chain ranging from 4 to 6), which exhibit a liquid crystalline phase, and 6′-(diethylamino)-1′,2′-benzofluoran (BF) leuco dye are reported. The main aim of this work is to investigate how the mo...

In this article, fully biodegradable films based on high methylated (HM) apple pectin, glycerol, and margarine were made. The influence of different crosslinking agents on the structure and functional properties of the obtained films was investigated. Fourier-transform infrared spectroscopy (FTIR), thermogravimetry (TG), differential scanning calor...

The development of a Spectrally Programmable Liquid‐State Active System for High‐performance (SPLASH) is introduced, which allows for multicolor lasing and White Emission. This completely liquid, three‐phase device showcases exceptional tunability within a singular Liquid Crystal Cell (LCC). Components include a Coumarin 540 (CM540)‐doped liquid cr...

Research is underway to find organic dyes with high photoluminescence quantum yield (QY) and compatibility with liquid crystals (LCs) that would be suitable for application in LC systems such as...

New trends towards development of integrated optics and miniaturization of photonic devices require fabrication of miniaturized photonic components. Fabrication of waveguiding films with designed optical properties is a fundamental process for production of planar integrated devices. We report here preparation of thin layers based on TiO2 precursor...

Mixtures of nematic liquid crystals (LCs) with chiral ionic liquids (CILs) may find application as active materials for electrically driven broadband mirrors. Five nematic liquid crystal hosts were mixed with twenty three ionic liquids, including chiral ones, and studied in terms of their miscibility within the nematic phase. Phase diagrams of the...

A series of liquid crystalline polyurethanes based on 4,4’-bis(hydroxyhexoxy)biphenyl moieties and modified by Trisilanolisobutyl-POSS (TRIS-POSS) was synthesized via a polyaddition reaction. ATR-FTIR confirmed introduction of POSS moieties into the macrochain. Formation of liquid crystalline phases along with higher melting and crystallization tem...

Series of organic acids with various strength were mixed with chiral liquid crystalline 4-phenylpyridine derivative and tendency of these acid-base mixtures to form either intermolecular hydrogen-bonded associates or ionic systems was characterized basing on mid-infrared absorption spectroscopy. For this purpose several liquid crystalline 4-carboxy...

In this work, we report for the first time on the influence of polyhedral oligomericsilsesquioxanes (POSS) on the structure and properties of liquid crystalline polyurethane (LCPU). LCPU/POSS hybrids were synthesized via a two-step method. In the first step, 4,4′-methylenephenyl diisocyanate (MDI) and polytetramethylene ether glycol (PTMG) reacted...

Planar photonic components can be fabricated with high resolution by electron beam patterning of polymer thin films on solid substrates such as silicon or glass. However, polymer films are normally formed by spin-coating of lithographic resists containing not only polymers but also volatile solvents, which is a serious environmental and health issu...

Four chiral dopants exhibiting smectic LC phases themselves were prepared and their helical twisting power (HTP) and thermal phase behaviour in mixtures with four various LC hosts were studied. The influence of host liquid crystal on HTP was evaluated and generally higher values were found for hosts with high birefringence. Unexpectedly, high enhan...

We report the new fluorescent polymerizable imidazolium-based ionic liquids for photonics application. We investigate two approaches: one ionic liquid (IL) contains the active fluorescein dianion as an intrinsic part of the polymerizable ionic liquid structure. The second liquid is based on the mixture of polymerizable ionic liquid with optically a...

The electron beam patterning is an important technology for fabrication of miniaturized photonic devices. The fabrication process conventionally involves usage of radiation sensitive polymer-based solutions (called resists). We propose to replace typical polymer resists with eco-friendly solvent-free room-temperature ionic liquids (RTILs), which ar...

Formation of gratings upon alternating electric field in compositions of highly birefringent liquid crystal (LC) with novel chiral ionic liquid (CIL) enclosed in 10-µm-thick cells is studied. The compatibility of two organic components of the mixture is investigated. The grating is formed in 1–5% CIL mixtures and causes significant changes of the t...

We present some approaches for modulation of light by hybrid liquid crystal materials. Mixtures of liquid crystals with chiral ionic liquids are used for modulating the incident light amplitude by alternative electric field. Hybrid cells of liquid crystals with inner surfaces, being modified by metallic and semiconductor nanoparticles, are used for...

Characterization of size of synthesized semiconductor copper indium sulphide (CuInS2) nanoparticles used for doping liquid crystal E7 is presented. The method of production of uniform dispersions of the nanoparticles in liquid crystals avoiding aggregation of the nanoparticles is discussed. It was possible to prepare doped liquid crystal with almos...

A pattern of liquid crystalline droplets dispersed in the isotropic liquid can be formed during illumination by two interfering laser beams in certain range of the temperature and the light intensity. Azobenzene derivative substituted by long alkyl and alkoxy chains exhibiting smectic phases has been used for the study. The pattern can be reversibl...

Growth dynamics of single isotropic domains, appearing in liquid crystalline azobenzene derivative during diffraction grating recording has been studied under the polarized microscope. Theoretical approach considering light stimulation as main reason of the growth has been proposed. Growth dynamics of population of the domains has been studied by f...

In this paper, we propose and explain the mechanism of dynamic molecular motions and isotropic domain formation during the diffraction grating recording in low molecular liquid-crystalline azobenzene derivatives. The photochromic molecules of 4-heptyl-4'-methoxyazobenzene, showing nematic liquid-crystalline properties close to the room temperature...

We present results of studies of the systems containing photochromic molecules, for all-optical switching and amplified spontaneous emission applications. The systems consisted of: a) deoxyribonucleic acid doped with different photochromic molecules like Disperse Orange 3 or spiropyranes, and b) photochromic molecules of 4-heptyl-4'- methoxyazobenz...

We present results of fast switching of birefringence changes and diffraction grating recording in a photochromic liquid crystalline molecules, showing liquid-crystalline nematic state close to the room temperature. Dynamic birefringence switching is done in Optical Kerr Effect setup and holographic recording of phase-type gratings is performed in...

The goal of the investigations was to measure the dynamics of photoinduced motions in semicrystalline polybutadiene backbone based polymer grafted with various degree of mesogenic thiols. We studied the influence of the grafting degree of the azobenzene-containing side groups and the length of terminal oxyaliphatic substituent in the side groups on...

The influence of temperature on dynamic grating recording in pure azobenzene derivative liquid crystalline molecules is studied. The liquid crystalline system consisted of photochromic molecules of 4-alkyl-4′-alkoxyazobenzenes with different length of substituents, showing nematic liquid crystalline properties close to the room temperature (from T=...

In this article we present results of studies of dynamics of molecular reorientation with the use of Optical Kerr Effect (OKE) in a new organometallic ruthenium-acetylide complex containing azobenzene fragment. The samples of thin films of organometallic complex casted on glass plates were excited by the chopped cw laser (¿ = 532 nm, P = 20 mW ) or...

The goal of the investigations was to measure the dynamics of molecular reorientation in polybutadiene backbone based polymer grafted with photochromic thiols. Measurements were performed in a typical degenerate two- and four-wave mixing experiments, in which time constants of dynamic diffraction grating formation were determined. Holographic grati...