Konrad Cyprych

Physically transient photonics: random versus distributed feedback lasing based on nanoimprinted DNA.

Room-temperature nanoimprinted, DNA-based distributed feedback (DFB) laser operation at 605 nm is reported. The laser is made of a pure DNA host matrix doped with gain dyes. At high excitation densities, the emission of the untextured dye-doped DNA films is characterized by a broad emission peak with an overall line width of 12 nm and superimposed narrow peaks, characteristic of random lasing. Moreover, direct patterning of the DNA films is demonstrated with a resolution down to 100 nm, enabling the realization of both surface-emitting and edge-emitting DFB lasers with a typical line width of <0.3 nm. The resulting emission is polarized, with a ratio between the TE- and TM-polarized intensities exceeding 30. In addition, the nanopatterned devices dissolve in water within less than 2 min. These results demonstrate the possibility of realizing various physically transient nanophotonics and laser architectures, including random lasing and nanoimprinted devices, based on natural biopolymers.

Coherent–incoherent random lasing based on nano-rubbing induced cavities

In this letter we present the results of studies carried out on poly(n-vinylcarbazole) doped with the well-known DCM laser dye. We show that the simple incorporation of highly luminescent dye into a polymeric matrix can form an efficient solid state laser material. Naturally occurring inhomogeneities of a polymeric layer prepared by a drop casting process can scatter out light emitted in the process of photoluminescence in such a way that feedback is introduced to the system and coherent and incoherent random lasing can be observed. Moreover we show that after a nano-scale rubbing process the random lasing phenomenon occurs for a lower energy density of pumping light as compared to the virgin sample, and changes the light amplification nature from incoherent to coherent.

Tunable wavelength light emission and amplification in Rhodamine 6G aggregates

Abstract In this work, the authors present experimental results of tunable amplified spontaneous emission (ASE) and random lasing (RL) emission wavelength, which mechanism is based on Rhodamine 6G (Rh6G) aggregates formation. Dye concentration controlled light amplification has been applied for RL and ASE on Rhodamine-doped biopolymeric layers like modified deoxyribonucleic acid (DNA) or starch. Additionally, measurements of ASE from water suspension with and without phosphatidylcholine (PC) lipids, confirmed Rhodamine aggregates role on different wavelength emission of ASE and RL. There have been acquired wide tuning of lasing equal to 35 nm observed for different studied biological systems.

Spontaneous crystalization and aggregation of DCNP pyrazoline-based organic dye as a way to tailor random lasers

The 3-(1,1-dicyanoethenyl)-1-phenyl-4,5-dihydro-1H-pyrazole (DCNP) compound is showing versatile optical features including nonlinear optical effects, photoluminescence and stimulated emission resulting from its molecular design as well as polar alignment in crystal lattice. We present detailed studies carried out for the DCNP compound on a photoluminescence phenomenon, showing that its emission properties are strongly different for molecular and aggregated forms. Experiments have proved that stimulated emission can occur only from the crystaline form of DCNP and the precipitation of it from a solution leads to the constitution of gain and different, random feedback mechanisms depending on aggregate size. The immobilization of DCNP crystals and the controlled crystalization in a viscous biopolymeric matrix have been utilized to generate random micro-cavities, that support weak light localization and coherent random laser emission.

Lasing and random lasing based on organic molecules

In this article we present the results of studies carried out on the selected polymeric systems doped with luminescent dyes. Our studies focused on polymers like DNA-CTMA and PVK which were doped with common laser dyes Rh6G and DCM. We show that simple incorporation of highly luminescent dye into polymeric matrix can form ;efficient solid laser materials. Moreover, naturally occurring inhomogeneities of polymeric layers prepared by a drop casting process can scatter out pumping light in such a way that a feedback is introduced to the system and coherent and incoherent random lasing can be observed.

Random lasing in dye doped bio-organic based systems: recent experiments and stochastic approach

We review the results of recent experimental studies on random lasing phenomenon in biopolymeric matrices: DNA-CTMA and starch, loaded with different luminescent dyes (DCNP and Rh6G). New experimental results for DNA-CTMA:DCNP system are presented. The random lasing originates due to the light scattering induced by formation of microcrystals or clusters in the bulk of biosystem. We propose a simple model for light transport in the scattering medium accounting for the inhomogeneities in polymer matrices simulated using Monte Carlo method and present some preliminary results related to ray scattering.

Random lasing in liquid and solid solutions oversaturated with organic laser dye

We present the results of studies carried out for oversaturated solutions with common laser dye 4- (Dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran (DCM) and 3-(1,1-Dicyanoethenyl)-1-phenyl-4,5- dihydro-1H-pyrazole (DCNP) nonlinear chromophore. We show that oversaturating the solution leads to formation of crystals suspension resulting in strong Mie scattering and thus random laser operation can be observed. The formation of aggregates can be induced be oversaturating the solution or by injection of non-solvent to the dye solution, leading to reduction of solubility limit. Similar situation can be obtained for polymeric matrices for which small crystals are precipitated during layer formation (solvent evaporation) when film is casted from the solution.

Stacked electrospun polymer nanofiber heterostructures with tailored stimulated emission

Bichromatic stimulated emission is achieved from electrospun hierarchical heterostructures with physically prevented donor quenching.

Random lasing in bio-polymeric dye-doped systems

The potential for photonic application of modified deoxyribonucleic acid with cationic surfactant cetyltrimethylammonium chloride, has been shown in many fields. Here we present results of detailed studies on random lasing achieved in a biopolymer based matrix loaded with luminescent dye. The random lasing originates due to the light scattering induced by formation of nanocrystals in the bulk biosystem. We show that lasing parameters for bio-polymeric system can be comparable with similar systems based on standard or π-conjugated polymers and may contribute to commercialization of polymeric lasers.