Time-resolved imaging of explosive phase change in metals

2007 ◽  
Author(s):  
Cristian Porneala ◽  
David A. Willis
Keyword(s):  
Phase Change ◽  
Time Resolved ◽  
Explosive Phase ◽  
Time Resolved Imaging

Nanosecond Time-Resolved Measurements of Transient Hole Opening During Laser Micromachining of an Aluminum Film

2013 ◽  
Vol 135 (9) ◽  
Author(s):  
Mohammad Hendijanifard ◽  
David A. Willis
Keyword(s):  
Shock Wave ◽  
Phase Change ◽  
Pulse Width ◽  
Laser Micromachining ◽  
Aluminum Film ◽  
Dye Laser ◽  
Time Resolved ◽  
Recoil Pressure ◽  
Hole Area ◽  
Explosive Phase

Laser micromachining of an aluminum film on a glass substrate is investigated using a time-resolved transmission imaging technique with nanosecond resolution. Micromachining is performed using a 7 ns pulse-width Nd:YAG laser operating at the 1064 nm wavelength for fluences ranging from 2.2 to 14.5 J/cm2. A nitrogen laser-pumped dye laser with a 3 ns pulse-width and 500 nm wavelength is used as a light source for visualizing the transient hole area. The dye laser is incident on the free surface and a CCD camera behind the sample captures the transmitted light. Images are taken from the back of the sample at various time delays with respect to the beginning of the ablation process, allowing the transient hole area to be measured. For low fluences, the hole opening process is delayed long after the laser pulse and there is significant scatter in the data due to weak driving forces for hole opening. However, for fluences at and above 3.5 J/cm2, the starting time of the process converges to a limiting minimum value of 12 ns, independent of laser fluence. At these fluences, the rate of hole opening is rapid, with the major portion of the holes opened within 25 ns. The second stage of the process is slower and lasts between 100 and 200 ns. The rapid hole opening process at high fluences can be attributed to recoil pressure from explosive phase change. Measurements of the transient shock wave position using the imaging apparatus in shadowgraph mode are used to estimate the pressure behind the shock wave. Recoil pressure estimates indicate pressure values over 90 atm at the highest fluence, which decays rapidly with time due to expansion of the ablation plume. The recoil pressure for all fluences above 3.1 J/cm2 is higher than that required for recoil pressure driven flow due to the transition to explosive phase change above this fluence.

scholarly journals Giant enhancement of THz-frequency optical nonlinearity by phonon polariton in ionic crystals

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yao Lu ◽  
Qi Zhang ◽  
Qiang Wu ◽  
Zhigang Chen ◽  
Xueming Liu ◽  
...  
Keyword(s):  
Near Infrared ◽  
Optical Nonlinearity ◽  
Ionic Crystals ◽  
Nonlinear Optical Susceptibility ◽  
Time Resolved ◽  
Light Coupling ◽  
Tremendous Progress ◽  
Fundamental Research ◽  
Ionic Contribution ◽  
Time Resolved Imaging

AbstractThe field of nonlinear optics has grown substantially in past decades, leading to tremendous progress in fundamental research and revolutionized applications. Traditionally, the optical nonlinearity for a light wave at frequencies beyond near-infrared is observed with very high peak intensity, as in most materials only the electronic nonlinearity dominates while ionic contribution is negligible. However, it was shown that the ionic contribution to nonlinearity can be much larger than the electronic one in microwave experiments. In the terahertz (THz) regime, phonon polariton may assist to substantially trigger the ionic nonlinearity of the crystals, so as to enhance even more the nonlinear optical susceptibility. Here, we experimentally demonstrate a giant second-order optical nonlinearity at THz frequency, orders of magnitude higher than that in the visible and microwave regimes. Different from previous work, the phonon-light coupling is achieved under a phase-matching setting, and the dynamic process of nonlinear THz generation is directly observed in a thin-film waveguide using a time-resolved imaging technique. Furthermore, a nonlinear modification to the Huang equations is proposed to explain the observed nonlinearity enhancement. This work brings about an effective approach to achieve high nonlinearity in ionic crystals, promising for applications in THz nonlinear technologies.

scholarly journals Time-resolved imaging refractometry of microbicidal films using quantitative phase microscopy

2011 ◽  
Vol 16 (12) ◽  
pp. 120510 ◽  
Author(s):  
Matthew T. Rinehart ◽  
Tyler K. Drake ◽  
Francisco E. Robles ◽  
Lisa C. Rohan ◽  
David Katz ◽  
...  
Keyword(s):  
Time Resolved ◽  
Quantitative Phase ◽  
Phase Microscopy ◽  
Quantitative Phase Microscopy ◽  
Time Resolved Imaging

scholarly journals Time-Resolved Imaging of Electrochemical Switching in Nanoscale Resistive Memory Elements

2015 ◽  
Vol 21 (S3) ◽  
pp. 1911-1912
Author(s):  
William A. Hubbard ◽  
E. R. White ◽  
Alexander Kerelsky ◽  
G. Jasmin ◽  
Jared J. Lodico ◽  
...  
Keyword(s):  
Resistive Memory ◽  
Time Resolved ◽  
Time Resolved Imaging

scholarly journals Two-Photon Time-Gated In Vivo Imaging of Dihydrolipoic-Acid-Decorated Gold Nanoclusters

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7744
Author(s):  
Ye Tian ◽  
Ming Wei ◽  
Lijun Wang ◽  
Yuankai Hong ◽  
Dan Luo ◽  
...  
Keyword(s):  
In Vivo Imaging ◽  
Gold Nanoclusters ◽  
Photon Absorption ◽  
Gold Nanocluster ◽  
Time Resolved ◽  
Dihydrolipoic Acid ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Time Resolved Imaging

Due to the unique advantages of two-photon technology and time-resolved imaging technology in the biomedical field, attention has been paid to them. Gold clusters possess excellent physicochemical properties and low biotoxicity, which make them greatly advantageous in biological imaging, especially for in vivo animal imaging. A gold nanocluster was coupled with dihydrolipoic acid to obtain a functionalized nanoprobe; the material displayed significant features, including a large two-photon absorption cross-section (up to 1.59 × 105 GM) and prolonged fluorescence lifetime (>300 ns). The two-photon and time-resolution techniques were used to perform cell imaging and in vivo imaging.

scholarly journals The C-terminal helix 9 motif in rat cannabinoid receptor type 1 regulates axonal trafficking and surface expression

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Alexandra Fletcher-Jones ◽  
Keri L Hildick ◽  
Ashley J Evans ◽  
Yasuko Nakamura ◽  
Kevin A Wilkinson ◽  
...  
Keyword(s):  
Hippocampal Neurons ◽  
Secretory Pathway ◽  
Cannabinoid Receptor ◽  
Surface Expression ◽  
Surface Polarity ◽  
Time Resolved ◽  
Surface Stability ◽  
C Terminus ◽  
Time Resolved Imaging ◽  
Dual Mechanism

Cannabinoid type one receptor (CB1R) is only stably surface expressed in axons, where it downregulates neurotransmitter release. How this tightly regulated axonal surface polarity is established and maintained is unclear. To address this question, we used time-resolved imaging to determine the trafficking of CB1R from biosynthesis to mature polarised localisation in cultured rat hippocampal neurons. We show that the secretory pathway delivery of CB1R is axonally biased and that surface expressed CB1R is more stable in axons than in dendrites. This dual mechanism is mediated by the CB1R C-terminus and involves the Helix 9 (H9) domain. Removal of the H9 domain increases secretory pathway delivery to dendrites and decreases surface stability. Furthermore, CB1RΔH9 is more sensitive to agonist-induced internalisation and less efficient at downstream signalling than CB1RWT. Together, these results shed new light on how polarity of CB1R is mediated and indicate that the C-terminal H9 domain plays key roles in this process.

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