Entity

Time filter

Source Type


Heidt A.M.,Stellenbosch University | Heidt A.M.,Institute of Photonic Technology
Journal of the Optical Society of America B: Optical Physics | Year: 2010

Supercontinuum (SC) generation in all-normal dispersion photonic crystal fiber under high energy femtosecond pumping is numerically investigated. It is shown that coherent octave spanning SC spectra with flatness of better than ±1 dB can be achieved over the entire bandwidth. A single pulse is maintained in the time domain, which may be externally compressed to the sub-10 fs regime even by simple linear chirp elimination. The single optical cycle limit is approached for full phase compensation, leading to peak power spectral densities of multiple kilowatts/nanometer. The generated SC is therefore ideal for applications which require high broadband spectral power densities as well as a defined pulse profile in the time domain. The properties of the generated SC are shown to be independent of the input pulse duration. © 2010 Optical Society of America.


Aviles-Espinosa R.,Institute of Photonic Technology
Journal of biomedical optics | Year: 2010

Live microscopy techniques (i.e., differential interference contrast, confocal microscopy, etc.) have enabled the understanding of the mechanisms involved in cells and tissue formation. In long-term studies, special care must be taken in order to avoid sample damage, restricting the applicability of the different microscopy techniques. We demonstrate the potential of using third-harmonic generation (THG) microscopy for morphogenesis/embryogenesis studies in living Caenorhabditis elegans (C. elegans). Moreover, we show that the THG signal is obtained in all the embryo development stages, showing different tissue/structure information. For this research, we employ a 1550-nm femtosecond fiber laser and demonstrate that the expected water absorption at this wavelength does not severely compromise sample viability. Additionally, this has the important advantage that the THG signal is emitted at visible wavelengths (516 nm). Therefore, standard collection optics and detectors operating near maximum efficiency enable an optimal signal reconstruction. All this, to the best of our knowledge, demonstrates for the first time the noninvasiveness and strong potential of this particular wavelength to be used for high-resolution four-dimensional imaging of embryogenesis using unstained C. elegans in vivo samples.


Wicker K.,Friedrich - Schiller University of Jena | Wicker K.,Institute of Photonic Technology
Optics Express | Year: 2013

The artefact-free reconstruction of structured illumination microscopy images requires precise knowledge of the pattern phases in the raw images. If this parameter cannot be controlled precisely enough in an experimental setup, the phases have to be determined a posteriori from the acquired data. While an iterative optimisation based on cross-correlations between individual Fourier images yields accurate results, it is rather timeconsuming. Here I present a fast non-iterative technique which determines each pattern phase from an auto-correlation of the respective Fourier image. In addition to improving the speed of the reconstruction, simulations show that this method is also more robust, yielding errors of typically less than ? /500 under realistic signal-to-noise levels. © 2013 Optical Society of America.


Schermelleh L.,Ludwig Maximilians University of Munich | Heintzmann R.,Kings College London | Heintzmann R.,Friedrich - Schiller University of Jena | Heintzmann R.,Institute of Photonic Technology | Leonhardt H.,Ludwig Maximilians University of Munich
Journal of Cell Biology | Year: 2010

For centuries, cell biology has been based on light microscopy and at the same time been limited by its optical resolution. However, several new technologies have been developed recently that bypass this limit. These new super-resolution technologies are either based on tailored illumination, nonlinear fluorophore responses, or the precise localization of single molecules. Overall, these new approaches have created unprecedented new possibilities to investigate the structure and function of cells. © 2010 Schermelleh et al.


Grant
Agency: Cordis | Branch: FP7 | Program: BSG-SME | Phase: SME-2012-1 | Award Amount: 1.48M | Year: 2013

Chemotherapy is the standard care for the treatment of non-small cell lung carcinoma (NSCLC) patients, however most of non-small cell lung cancer tumours are not sensitive to this treatment. As an alternative to chemoterapy, target therapy with gefitinib (epidermal growth factor receptor-tyrosine kinase inhibitor) has been used in clinical practice in patients with tumours harbouring mutations in EGFR gene, improving their treatment effectiveness. For that reason EGFR mutations analysis should be perform to support the treatment decision for a patient with NSCLC. Despite all the foreseen benefits of EGFR genotyping, the current PCR-based methods used have been shown some associated bottlenecks: i) use of complex samples (tumour biopsy embedded in Formalin Fixed Paraffin, FFPE), ii) require a better understanding from the clinical geneticist to accurately interpret the information provided and to setup the best line of therapy and treatment and iii) the assays are quite expensive and time-consuming. New age diagnostic tools, such as microfluidic platforms and nanodiagnostics are emerging technologies for DNA analysis requiring lower sample volumes and providing comparable sensitivity and specificity at lower costs. Nonetheless, sample preparation and detection of the result of a chemical analysis on-chip are still weak points in many lab-on-a-chip devices. The current proposal, aiming the integration of all laboratory-based process steps in one single step, is both challenging and feasible: development of a microfluidic chip that combines blood sample processing (DNA extraction/purification, multiplex amplification) and detection of EGFR mutations in tumour DNA by means of gold and silver-nanoparticles (Ag and Au-nanoprobes). Furthermore a microfluidic chip analyser with an integrated user-friendly software to report genotyping results will be developed.

Discover hidden collaborations