Amplified Dispersive Fourier-Transform Imaging for Ultrafast Displacement Sensing and Barcode Reading

Dispersive Fourier transformation is a powerful technique in which the spectrum of an optical pulse is mapped into a time-domain waveform using chromatic dispersion. It replaces a diffraction grating and detector array with a dispersive fiber and single photodetector. This simplifies the system and, more importantly, enables fast real-time measurements. Here we describe a novel ultrafast barcode reader and displacement sensor that employs internally-amplified dispersive Fourier transformation. This technique amplifies and simultaneously maps the spectrally encoded barcode into a temporal waveform. It achieves a record acquisition speed of 25 MHz -- four orders of magnitude faster than the current state-of-the-art.Comment: Submitted to a journa

Utility investigation of artificial time delay in displacement-noise-free interferometers

Laser interferometer gravitational wave detectors are usually limited by displacement noise in their lower frequency band. Recently, theoretical proposals have been put forward to construct schemes of interferometry that are insusceptible to displacement noise as well as classical laser noise. These so-called displacement-noise-free interferometry (DFI) schemes take advantage of the difference between gravitational waves and displacement noise in their effects on light propagation. However, since this difference diminishes in lower frequencies (i.e., Omega>[script L]D/c) into the interferometry scheme, with the hope of improving low-frequency sensitivity. We found that sensitivity can only be improved by schemes in which fluctuations in the artificial time delays are not canceled

Theory of amplified dispersive Fourier transformation

Amplified dispersive Fourier transformation (ADFT) is a powerful technique that maps the spectrum of an optical pulse into a time-domain waveform using group-velocity dispersion (GVD) and simultaneously amplifies it in the optical domain. It replaces a diffraction grating and detector array with a dispersive fiber and single photodetector, greatly simplifying the system and, more importantly, enabling ultrafast real-time spectroscopic measurements. Here we present a theory of ADFT by deriving the general equation and spectral resolution for ADFT and studying the evolution of the pulse spectrum into time, the effect of GVD coefficients on ADFT, and the requirement for dispersion. This theory is expected to lend valuable insights into the process and implementation of ADFT. © 2009 The American Physical Society.published_or_final_versio

Theory of amplified dispersive Fourier transformation

Amplified dispersive Fourier transformation (ADFT) is a powerful technique that maps the spectrum of an optical pulse into a time-domain waveform using group-velocity dispersion (GVD) and simultaneously amplifies it in the optical domain. It replaces a diffraction grating and detector array with a dispersive fiber and single photodetector, greatly simplifying the system and, more importantly, enabling ultrafast real-time spectroscopic measurements. Here we present a theory of ADFT by deriving the general equation and spectral resolution for ADFT and studying the evolution of the pulse spectrum into time, the effect of GVD coefficients on ADFT, and the requirement for dispersion. This theory is expected to lend valuable insights into the process and implementation of ADFT. © 2009 The American Physical Society.published_or_final_versio

Simultaneous mechanical-scan-free confocal microscopy and laser microsurgery

We demonstrate an endoscope-compatible single-fiber-based device that performs simultaneous confocal microscopy and high-precision laser microsurgery. The method is based on mapping of two-dimensional sample coordinates onto the optical spectrum and allows us to perform two-dimensional imaging and microsurgery without any mechanical movement of the probe or the sample. The technology holds promise for creating highly miniaturized endoscopes for applications such as brain tumor, pediatric, and endovascular surgeries where high-precision, small, and flexible probes are required. © 2009 Optical Society of America.published_or_final_versio

Performance of serial time-encoded amplified microscope

Serial time-encoded amplified microscopy (STEAM) is an entirely new imaging modality that enables ultrafast continuous real-time imaging with high sensitivity. By means of optical image amplification, STEAM overcomes the fundamental tradeoff between sensitivity and speed that affects virtually all optical imaging systems. Unlike the conventional microscope systems, the performance of STEAM depends not only on the lenses, but also on the properties of other components that are unique to STEAM, namely the spatial disperser, the group velocity dispersion element, and the back-end electronic digitizer. In this paper, we present an analysis that shows how these considerations affect the spatial resolution, and how they create a trade-off between the number of pixels and the frame rate of the STEAM imager. We also quantify how STEAM's optical image amplification feature improves the imaging sensitivity. These analyses not only provide valuable insight into the operation of STEAM technology but also serve as a blue print for implementation and optimization of this new imaging technology. ©2010 Optical Society of America.published_or_final_versio

Calculation Of Pressure Rise And Energy Of Hot Gases Due To High Energy Arcing Faults In The Metal-clad Switchgear

This paper presents the 3-D CFD calculation results of the pressure rise due to the High Energy Arcing Faults (HEAFs) in the metal-clad switchgears. The calculations were performed considering the came-off of the roof panel that was observed in the arc tests. The calculated pressure development approximately agreed with the measured one. Furthermore, the energy of hot gases exhausted from the broken roof panel was calculated to investigate the thermal effect of hot gases

Update on targeted cancer therapies, single or in combination, and their fine tuning for precision medicine

Background: Until recently, patients who have the same type and stage of cancer all receive the same treatment. It has been established, however, that individuals with the same disease respond differently to the same therapy. Further, each tumor undergoes genetic changes that cause cancer to grow and metastasize. The changes that occur in one person's cancer may not occur in others with the same cancer type. These differences also lead to different responses to treatment. Precision medicine, also known as personalized medicine, is a strategy that allows the selection of a treatment based on the patient's genetic makeup. In the case of cancer, the treatment is tailored to take into account the genetic changes that may occur in an individual's tumor. Precision medicine, therefore, could be defined in terms of the targets involved in targeted therapy. Methods: A literature search in electronic data bases using keywords “cancer targeted therapy, personalized medicine and cancer combination therapies” was conducted to include papers from 2010 to June 2019. Results: Recent developments in strategies of targeted cancer therapy were reported. Specifically, on the two types of targeted therapy; first, immune-based therapy such as the use of immune checkpoint inhibitors (ICIs), immune cytokines, tumor-targeted superantigens (TTS) and ligand targeted therapeutics (LTTs). The second strategy deals with enzyme/small molecules-based therapies, such as the use of a proteolysis targeting chimera (PROTAC), antibody-drug conjugates (ADC) and antibody-directed enzyme prodrug therapy (ADEPT). The precise targeting of the drug to the gene or protein under attack was also investigated, in other words, how precision medicine can be used to tailor treatments. Conclusion: The conventional therapeutic paradigm for cancer and other diseases has focused on a single type of intervention for all patients. However, a large literature in oncology supports the therapeutic benefits of a precision medicine approach to therapy as well as combination therapies

Mit der Magnetresonanztomographie selektierbare Läsionen und Korrelation mit klinischen Parametern bei Patienten mit affektiven Störungen

Es gibt Berichte über Zusammenhänge zwischen Hirnläsionen und dem Auftreten von affektiven Störungen. Diese gingen meist von einer geringen Fallzahl aus und die Evaluierung psychiatrischer Patienten war ungenügend. An 101 Patienten und einem alters- und geschlechtsangepassten Vergleichskollektiv wurden anamnestische Daten ermittelt und ein MRT des Schädels nach dem Vorhandensein, Anzahl, Größe und Spezifität von Läsionen ausgewertet. Das Hauptergebnis dieser Studie war, dass unipolare Patienten überzufällig häufiger frontale Läsionen als Kontrollen aufwiesen. Patienten hatten dabei ausschliesslich unspezifische Läsionen, Kontrollen meist mikroangiopathische Veränderungen. Bei den Patienten schienen bekannte Risikofaktoren nicht zu einem vermehrten Auftreten von Läsionen zu führen, das unterstützt die These, dass es bei unipolaren Patienten sinnvoll ist eine Sonderform von Depressionen („late onset depression“) in die Einteilung der Depressionen mit einzubeziehen

Effects of mode degeneracy in the LIGO Livingston Observatory recycling cavity

We analyze the electromagnetic fields in a Pound-Drever-Hall locked, marginally unstable, Fabry-Perot cavity as a function of small changes in the cavity length during resonance. More specifically, we compare the results of a detailed numerical model with the behavior of the recycling cavity of the Laser Interferometer Gravitational-wave Observatory (LIGO) detector that is located in Livingston, Louisiana. In the interferometer's normal mode of operation, the recycling cavity is stabilized by inducing a thermal lens in the cavity mirrors with an external CO2 laser. During the study described here, this thermal compensation system was not operating, causing the cavity to be marginally optically unstable and cavity modes to become degenerate. In contrast to stable optical cavities, the modal content of the resonating beam in the uncompensated recycling cavity is significantly altered by very small cavity length changes. This modifies the error signals used to control the cavity length in such a way that the zero crossing point is no longer the point of maximum power in the cavity nor is it the point where the input beam mode in the cavity is maximized.Comment: Eight pages in two-column format. Six color figures. To be published JOSA