Stimulated Emission from Rhodamine 6G Aggregates Self-Assembled on Amyloid Protein Fibrils

Amyloid fibrils are excellent bioderived nanotemplates for controlling molecular and optical properties of small molecules such as organic dyes. Here we demonstrate that two representative fibril-forming proteins, lysozyme and insulin, from the amyloids family can determine the optical signature of rhodamine 6G. Their structural variety leads to a unique molecular arrangement of dye aggregates on the biotemplate surface. This significantly influences the light amplification threshold as well as the stimulated emission profiles, which show remarkable broadband wavelength tunability. We show in addition that amyloid fibrils can be potentially used in constructing broadband emission biolasers

Amplified spontaneous emission in the spiropyran-biopolymer based system

Amplified spontaneous emission (ASE) phenomenon in the 6-nitro-1′,3′,3′-trimethylspiro[2H-1-benzopyran-2,2′-indolin] organic dye dispersed in a solid matrix has been observed. The biopolymer system deoxyribonucleic acid blended with cationic surfactant molecule cetyltrimethyl-ammonium chloride served as a matrix. ASE appeared under sample excitation by UV light pulses (λ=355 nm) coming from nanosecond or picosecond neodymium doped yttrium aluminum garnet lasers and has been reinforced with green (λ=532 nm) light excitation followed UV light pulse. The ASE characteristics in function of different excitation pulse energies as well as signal gain were measured

Influence of surfactant on dynamics of photoinduced motions and light emission of a dye-doped deoxyribonucleic

Pure deoxyribonucleic acid (DNA) is known to be soluble in water only and exhibits poor temperature stability. In contrary, it is well known that the complex of DNA - with cetyltrimethyl ammonium (CTMA) is insoluble in water but soluble in alcohols and can be processed into very good optical quality thin films by solution casting or spin deposition. Despite the success of DNA-CTMA, there is still need for new cationic surfactants which would extend the range of available solvents for DNA complex. We test and present experimental results of influence of new surfactants replacing CTMA in the DNA complex and based on benzalkonium chloride (BA) and didecyldimethylammonium chloride (DDCA) on their optical properties. Particularly, we were interested in all optical switching and light generation in amplified spontaneous emission process in these materials

Amplified spontaneous emission of Rhodamine 6G embedded in pure deoxyribonucleic acid

Deoxyribonucleic acid (DNA) is commonly viewed as a genetic information carrier. However, now it is recognized as a nanomaterial, rather than as a biological material, in the research field of nanotechnology. Here, we show that using pure DNA, doped with rhodamine 6G, we are able to observe amplified spontaneous emission (ASE) phenomenon. Moderate ASE threshold, photodegradation, and reasonable gain coefficient observed in this natural host gives some perspectives for practical applications of this system in biophotonics. Obtained results open the way and will be leading to construction of truly bio-lasers using nature made luminophores, such as anthocyanins

Biomineral Amorphous Lasers through Light-Scattering Surfaces Assembled by Electrospun Fiber Templates

New materials aim at exploiting the great control of living organisms over molecular architectures and minerals. Optical biomimetics has been widely developed by microengineering, leading to photonic components with order resembling those found in plants and animals. These systems, however, are realized by complicated and adverse processes. Here we show how biomineralization might enable the one-step generation of components for amorphous photonics, in which light is made to travel through disordered scattering systems, and particularly of active devices such as random lasers, by using electrospun fiber templates. The amount of bio-enzymatically produced silica is related to light-scattering capacity and the resulting organosilica surfaces exhibit a transport mean free path for light as low as 3 micron, and lasing with linewidth below 0.2 nm. The resulting, complex optical material is characterized and modelled to elucidate scattered fields and lasing performance. Tightly-controlled nanofabrication of direct biological inspiration establishes a new concept for the additive manufacturing of engineered light-diffusing materials and photonic components, not addressed by existing technologies.Comment: 37 pages, 11 figure

"Siihen se tarina loppuu" Osallisuuden tukeminen saduttamalla

Opinnäytetyö oli toiminnallinen opinnäytetyö, jonka tavoitteena oli osallisuuden tukeminen sadutusmenetelmää hyödyntäen ja työn tarkoituksena oli myös tuottaa satukirja lasten kertomista saduista. Opinnäytetyö toteutettiin yhteistyössä päiväkoti Touhula Kangasalan kanssa kevään 2018 aikana. Työn tietoperusta koostui sadutuksesta, osallisuudesta, lasten kuulluksi tulemisesta, sekä varhaiskasvatuksesta. Opinnäytetyön toiminnallisessa osuudessa yksilösadutettiin lapsia ja näistä saduista koottiin työn liitteissä oleva satukirja. Lapset saivat kuvittaa omat satunsa ja kuvat liitettiin osaksi satukirjaa. Toiminnallinen osuus toteutettiin huhtikuussa 2018 ja sen aikana sadutettiin seitsemää 4-5-vuotiasta lasta. Työn tilaaja sai opinnäytetyön aikana syntyneen satukirjan jaettavaksi toiminnalliseen osuuteen osallistuneille lapsille. Lapset saivat antaa palautetta valmiista satukirjasta ja palaute heiltä oli positiivista. Lisäksi työ auttoi tukemaan lasten osallisuutta saduttamisen yhteydessä sekä opinnäytetyö toivottavasti innosti päiväkodin henkilökuntaa käyttämään sadutusmenetelmää myös tulevaisuudessa.This Bachelor’s thesis was practice-based and the aim was to support inclusion in the daycare centre Touhula in Kangasala by using the storycrafting method. Another goal was to make a storybook from the stories the children told. The thesis was implemented in spring 2018. The theoretical background consists of the storycrafting method, inclusion, what being heard is and early childhood education. In the practice part of the thesis, seven children aged four to five attended individual storycrafting sessiona. The children drew pictures to their stories and the stories were collected into a storybook. This practice part was carried out in April 2018. The Touhula Kangasala daycare centre received the finished storybook in May 2018. The children who took part into the storycrafting, also received copies of the storybook. The children also gave feedback about the book. The feedback was positive and the main aim of the thesis, to support the inclusion in the group, was achieved. The thesis also hopefully inspired the personnel to use the storycrafting method in the future

Electrically controlled white laser emission through liquid crystal/polymer multiphases

White lasers are becoming increasingly relevant in various fields since they exhibit unprecedented properties in terms of beam brightness and intensity modulation. Here we introduce a white laser based on a polymer matrix encompassing liquid crystals and multiple organic chromophores in a multifunctional phase-separation system. The separation of the hydrophilic matrix and the hydrophobic liquid crystals leads to the formation of a complex optically active layer, featuring lasing emission tuneable from blue to red. White laser emission is found with an optical excitation threshold of approximately 12 mJ/cm2. Importantly, an external electric field can be used to control the device emission intensity. White lasers with low-voltage (≤10 V) controllable emission might pave the way for a new generation of broadband light sources for analytical, computational, and communication applications

Interplay of Stimulated Emission and Fluorescence Resonance Energy Transfer in Electrospun Light-Emitting Fibers

Concomitant amplified spontaneous emission (ASE) and Förster resonance energy transfer (FRET) are investigated in electrospun light-emitting fibers. Upon dye-doping with a proper FRET couple system, free-standing fibrous mats exhibit tunable FRET efficiency and, more importantly, tailorable threshold conditions for stimulated emission. In addition, effective scattering of light is found in the fibrous material by measuring the transport mean free path of photons by coherent backscattering experiments. The interplay of ASE and FRET leads to high control in designing optical properties from electrospun fibers, including the occurrence of simultaneous stimulated emission from both donor and acceptor components. All tunable-optical properties are highly interesting in view of applying electrospun light-emitting materials in lightening, display, and sensing technologies

Study of the amplified spontaneous emission in a dye-doped biopolymer-based material

In this paper we investigate the amplified spontaneous emission (ASE) phenomenon in the system based on a dye dissolved in a modified deoxyribonucleic acid (DNA). The system consisted of a biopolymeric matrix made of DNA blended with cationic surfactant molecule cetyltrimethyl-ammonium chloride (CTMA) and doped with a well-known rhodamine (Rh 6G) laser dye. Thin films of the DNA–CTMA : Rh6G were excited at λ = 532 nm wavelength with 8 ns laser pulses. We report on ASE intensity as a function of the laser power, dependence of polarization state of the excitation beam, ASE gain and temporal stability of the signal for the investigated system