TY - JOUR A1 - Melekhov, Evgeny A1 - Penn, Tatjana A1 - Weidauer, Tobias A1 - Abb, Valerius A1 - Kammler, Martin A1 - Lechner, Alfred T1 - Tunable nanopillar array on a quartz-fiber tip for surface enhanced Raman scattering (SERS) detection JF - tm - Technisches Messen N2 - In this work, a simple two-step method to create tunable self-assembled three-dimensional nanostructure array-like nanoantennas directly on the tip of an optical quartz glass fiber is described. The structures are prepared by using dry etching of the fiber tip. For the etching process, gold nanoparticles fabricated by thermal dewetting technique were used as template. The structures are applied as sensors for label-free analysis of organic substances in ppb range, such as drug residues in liquid solutions. The measurements are carried out by a portable Raman device with an exchangeable sensor head utilizing the SERS-effect. This method allows in situ applications. In order to characterize the SERS cells, para-thiocresol and diclofenac sodium are used as model substances. For optimization of the substrate performance, different thicknesses of the dewetting-layer (6, 9, 12 nm), different etching times for formation of the pillars (6, 8, 10 and 12 min), and different thicknesses of SERS-metallization (25, 50, 75 nm) of gold and silver are compared. In order to show the applicability of the structure on the tip of a fiber, measurements from the upper side and from the underside of the substrate on quartz plates are compared. Reproducible SERS enhancement factors up to 10 7 {10^{7}} were achieved. N2 - In dieser Arbeit wird eine zweistufige Methode beschrieben, um einstellbare selbstorganisierte dreidimensionale SERS-aktive Nanostrukturen in Form von Nanosäulen auf der Spitze einer optischen Quarzglasfaser herzustellen. Die Strukturen werden durch trockenchemisches Ätzen der Faserspitze erzeugt. Für den Ätzprozess werden als Maske Goldnanopartikel verwendet, die mittels Thermal Dewetting hergestellt werden. Der Sensor wird für eine markierungsfreie Analyse von organischen Substanzen, wie bspw. Medikamentenrückstände in wässrigen Lösungen, im ppb-Bereich eingesetzt. Die Messungen werden mit einem tragbaren Raman-Gerät mit einem austauschbaren Sensorkopf durchgeführt. Um die SERS-Zellen zu charakterisieren, werden para-Thiocresol und Diclofenac-Natrium als Modellsubstanzen verwendet. Zur Optimierung der Substratleistung werden unterschiedliche Dicken der Dewettinglayer (6, 9, 12 nm), unterschiedliche Ätzzeiten der Nanosäulen (6, 8, 10 und 12 min) und unterschiedliche Schichtdicken der SERS-Metallisierung (25, 50, 75 nm) von Gold und Silber verglichen. Um die Anwendbarkeit der Struktur an der Spitze einer Faser zu zeigen, werden Messungen von der Oberseite und von der Rückseite des Substrats in Form eines Quarzglasplatten verglichen. Diese Struktur liefert einen reproduzierbaren Verstärkungsfaktor von bis zu 107. T2 - Einstellbare Nanosäulenanordnung auf der Spitze einer Quarzglasfaser für oberflächenverstärkte Raman-Spektroskopie (SERS) Y1 - 2022 U6 - https://doi.org/10.1515/teme-2021-0093 VL - 89 IS - 1 SP - 70 EP - 81 PB - de Gruyter ER - TY - GEN A1 - Melekhov, Evgeny A1 - Abb, Valerius A1 - Weidauer, Tobias A1 - Kammler, Martin A1 - Lechner, Alfred T1 - Tunable Nanopillars as Surface Enhanced Raman Scattering (SERS) Active Structure for Optical Quartz Glass Fiber T2 - SMSI 2021 - Sensors and Instrumentation N2 - In this work, a simple cost effective method to create tunable self-assembled three-dimensional nanostructure array-like nanoantennas on a tip of an optical quartz glass fiber is described. The structures are prepared using lithography-less dry etching. Gold nanoparticles are used as an etching mask using a thin metal-film thermal dewetting technique. The structures are applied as sensor for label-free analysis of organic substances in ppb range, such as drug residues in groundwater. The measurements are carried out by means of a Surface-enhanced Raman scattering (SERS) effect, an exchangeable sensor head, and a portable Raman device. This method allows in situ applications. Parathiocresol is used as a model substance to characterize the SERS cells. For metallization, gold and silver are compared. Reproducible SERS enhancement factors up to 10 7 are evaluated. Y1 - 2021 SN - 978-3-9819376-4-0 U6 - https://doi.org/10.5162/SMSI2021/B8.2 SP - 153 EP - 154 PB - AMA Association for Sensors and Measurement ER - TY - CHAP A1 - Siders, C. W. A1 - Cavalleri, Andrea A1 - Tóth, Csaba A1 - Wilson, K. R. A1 - Squier, Jeff A. A1 - Barty, C. P. J. A1 - Kammler, Martin A1 - Sokolowski-Tinten, Klaus A1 - Horn-von Hoegen, Michael A1 - von der Linde, D. T1 - Femtosecond X-ray diffraction of short-pulse irradiated semiconductors T2 - Summaries of Papers Presented at the Lasers and Electro-Optics. CLEO '02. Technical Diges, 24-24 May 2002, Long Beach, CA, USA N2 - Summary form only given, as follow. Ultrafast optical-pump, X-ray diffraction probe experiments are providing new ways to study transient processes including the direct observation of the atomic motion by which many solid-state processes and chemical and biochemical reactions take place. Current table-top-terawatt femtosecond laser systems provide an attractive source of few-hundred femtosecond duration bursts of angstrom-scale X-ray radiation with fluxes comparable to standard rotating anode sources. Their compact size enables time resolved structural dynamics to be studied in the small laboratory with temporal resolution better than typical molecular vibrational periods. Ultrafast structural dynamics in crystalline samples are readily studied with such systems and experiments to be discussed in this talk include ultrafast non-thermal solid-to-liquid transition in thin single-crystal Ge-111 films grown on Si-111 substrates; ultrafast non-thermal solid-to-solid transitions in bulk vanadium dioxide from a low temperature insulating phase to a high temperature metallic phase; and harmonic and anharmonic coherent acoustic dynamics in layered Ge-111/Si-111 and bulk GaAs-111 samples. Future improvements in high-average power short-pulse lasers will enable the study of a wider class of materials such as amorphous solids or liquid-phase dynamics of simple molecules, while proposed 4th generation light sources based upon single-pass X-ray free-electron lasers will permit singleshot structural determination of complex biomolecules. KW - high-speed techniques KW - X-ray diffraction KW - laser beam effects KW - semiconductor materials KW - solid-liquid transformations KW - solid-state phase transformations KW - metal-insulator transition Y1 - 2002 U6 - https://doi.org/10.1109/CLEO.2002.1033997 SP - 297 EP - 298 PB - IEEE ER - TY - JOUR A1 - Sokolowski-Tinten, Klaus A1 - Horn-von Hoegen, Michael A1 - von der Linde, D. A1 - Cavalleri, Andrea A1 - Siders, C. W. A1 - Brown, F. L. H. A1 - Leitner, D. M. A1 - Tóth, Csaba A1 - Squier, Jeff A. A1 - Barty, C. P. J. A1 - Wilson, K. R. A1 - Kammler, Martin T1 - Transient lattice dynamics in fs-laser-excited semiconductors probed by ultrafast X-ray diffraction JF - Journal de Physique IV N2 - A study of lattice dynamics in fs-laser-excited crystalline bulk Ge and Ge/Si-heterostructures, using time-resolved x-ray diffraction, was presented. Fast energy transport deep into the bulk of the material, coherent acoustic phonon dynamics, lattice anharmonicity, and vibrational transport across a buried interfaces were observed. Graphs showing time-dependent shifts of the centroid of the measured rocking curves in the Ge-overlayer and in the Si-substrate for different fluences, were presented. Y1 - 2001 U6 - https://doi.org/10.1051/jp4:2001290 VL - 11 IS - Pr2 SP - 473 EP - 477 PB - EDP ER - TY - JOUR A1 - Cavalleri, Andrea A1 - Siders, C. W. A1 - Brown, F. L. H. A1 - Leitner, D. M. A1 - Tóth, Csaba A1 - Squier, Jeff A. A1 - Barty, C. P. J. A1 - Wilson, K. R. A1 - Sokolowski-Tinten, Klaus A1 - Horn-von Hoegen, Michael A1 - von der Linde, D. A1 - Kammler, Martin T1 - Anharmonic lattice dynamics in germanium measured with ultrafast x-ray diffraction JF - Physical review letters N2 - Damping of impulsively generated coherent acoustic oscillations in a femtosecond laser-heated thin germanium film is measured as a function of fluence by means of ultrafast x-ray diffraction. By simultaneously measuring picosecond strain dynamics in the film and in the unexcited silicon substrate, we separate anharmonic damping from acoustic transmission through the buried interface. The measured damping rate and its dependence on the calculated temperature of the thermal bath is consistent with estimated four-body, elastic dephasing times (T2) for 7-GHz longitudinal acoustic phonons in germanium. Y1 - 2000 U6 - https://doi.org/10.1103/PhysRevLett.85.586 VL - 85 IS - 3 SP - 586 EP - 589 PB - APS ER - TY - JOUR A1 - Sokolowski-Tinten, Klaus A1 - Cavalleri, Andrea A1 - Siders, C. W. A1 - Brown, F. L. H. A1 - Leitner, D. M. A1 - Tóth, Csaba A1 - Kammler, Martin A1 - Horn-von Hoegen, Michael A1 - von der Linde, D. A1 - Squier, Jeff A. A1 - Barty, C. P. J. A1 - Wilson, K. R. T1 - Time-resolved x-ray diffraction study of ultrafast acoustic phonon dynamics in Ge/Si-heterostructures JF - Chemical Physics N2 - Using time-resolved x-ray diffraction the ultafast strain dynamics in fs-laserexcited Ge/Si-heterostructures has been studied. A fluence dependent, anharmonic damping of the impulsively generated acoustic phonons and vibrational transport across the buried Ge/Si-interface are observed. Y1 - 2001 U6 - https://doi.org/10.1007/978-3-642-56546-5_81 VL - 66 SP - 281 EP - 283 PB - Springer ER - TY - JOUR A1 - Siders, C. W. A1 - Cavalleri, Andrea A1 - Sokolowski-Tinten, Klaus A1 - Tóth, Csaba A1 - Guo, T. A1 - Kammler, Martin A1 - Horn-von Hoegen, Michael A1 - Wilson, K. R. A1 - von der Linde, D. A1 - Barty, C. P. J. T1 - Direct Observation of Ultrafast Non-thermal Melting by Ultrafast X-ray Diffraction JF - Ultrafast Phenomena XII N2 - Ultrafast nonthermal melting of femtosecond laser-irradiated germanium was observed directly for the first time using sub-picosecond, 1.54-angstrom x-ray diffraction. Such measurements allow the study of transient atomic motion fundamental to many processes in physics, chemistry, and biology. Y1 - 2000 U6 - https://doi.org/10.1007/978-3-642-56546-5_80 VL - 66 SP - 276 EP - 280 PB - Springer ER - TY - JOUR A1 - Sokolowski-Tinten, Klaus A1 - Blome, Christian A1 - Blums, Juris A1 - Shymanovich, Uladzimir A1 - Nicoul, M. A1 - Cavalleri, Andrea A1 - Tarasevitch, A. A1 - Horn-von Hoegen, Michael A1 - Kammler, Martin A1 - von der Linde, D. T1 - Ultrafast X-ray diffraction JF - Ultrafast Phenomena XIV N2 - In the last few years the generation of femtosecond pulses in the X-ray regime has become possible. These ultrashort X-ray pulses have enabled femtosecond time- resolution to be extended to X-rays. Y1 - 2005 U6 - https://doi.org/10.1007/3-540-27213-5_53 VL - 79 SP - 170 EP - 174 PB - Springer ER - TY - JOUR A1 - Siders, C. W. A1 - Cavalleri, Andrea A1 - Sokolowski-Tinten, Klaus A1 - Tóth, Csaba A1 - Guo, T. A1 - Kammler, Martin A1 - Horn-von Hoegen, Michael A1 - Wilson, K. R. A1 - von der Linde, D. A1 - Barty, C. P. J. T1 - Detection of nonthermal melting by ultrafast X-ray diffraction JF - Science N2 - Using ultrafast, time-resolved, 1.54 angstrom x-ray diffraction, thermal and ultrafast nonthermal melting of germanium, involving passage through nonequilibrium extreme states of matter, was observed. Such ultrafast, optical-pump, x-ray diffraction probe measurements provide a way to study many other transient processes in physics, chemistry, and biology, including direct observation of the atomic motion by which many solid-state processes and chemical and biochemical reactions take place. Y1 - 1999 U6 - https://doi.org/10.1126/science.286.5443.1340 VL - 286 IS - 5443 SP - 1340 EP - 1342 ER - TY - CHAP A1 - Sokolowski-Tinten, Klaus A1 - Blome, Christian A1 - Blums, Juris A1 - Shymanovich, Uladzimir A1 - Nicoul, M. A1 - Cavalleri, Andrea A1 - Tarasevitch, A. A1 - Horn-von Hoegen, Michael A1 - Kammler, Martin A1 - von der Linde, Dietrich ED - Kobayashi, Tetsuro T1 - Ultrafast X-ray diffraction T2 - Ultrafast Phenomena XIV N2 - In the last few years the generation of femtosecond pulses in the X-ray regime has become possible. These ultrashort X-ray pulses have enabled femtosecond time- resolution to be extended to X-rays. Y1 - 2004 SN - 978-3-540-27213-7 U6 - https://doi.org/10.1007/3-540-27213-5_53 VL - 79 SP - 170 EP - 174 PB - Springer CY - Berlin, Heidelberg ER -