|
Double-Blind FROG
Double-blind frequency-resolved optical gating (double-blind FROG) is a method for simultaneously measuring two unknown ultrashort laser pulses. Well established ultrafast measurement techniques such as frequency-resolved optical gating and its simplified version GRENOUILLE can only measure one unknown ultrashort laser pulse at a time. Another version of FROG, called cross-correlation FROG (XFROG), also measures only one pulse, but it involves two pulses: a known reference pulse and the unknown pulse to be measured. In modern optics experiments, ultrashort laser pulses have been used in a great variety of engineering application and scientific research, for example, biomedical engineering, material science, nonlinear spectroscopy, ultrafast chemistry, etc. Often, these experiments involve using two potentially different input laser pulses, for example, Raman spectroscopy, two-color pump-probe experiments, and non-degenerate four-wave mixing. In many situations, an output pulse is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blind FROG Setup
Blind may refer to: * The state of blindness, being unable to see * A window blind, a covering for a window Blind may also refer to: Arts, entertainment, and media Films * ''Blind'' (2007 film), a Dutch drama by Tamar van den Dop * ''Blind'' (2011 film), a South Korean crime thriller * ''Blind'' (2014 film), a Norwegian drama * ''Blind'' (2016 film), an American drama * ''Blind'' (2019 film), an American horror film * ''Blind'' (upcoming film), an upcoming Indian crime thriller, based on 2011 South Korean film of the same name Music * Blind (band), Australian Christian rock group founded in 1999 * Blind (rapper), Italian rapper Albums * ''Blind'' (Corrosion of Conformity album), 1991 * ''Blind'' (The Icicle Works album), 1988 * ''Blind'' (The Sundays album), 1992 * ''Blind!'', a 1985 album by the Sex Gang Children Songs * "Blind" (Breed 77 song), 2006 * "Blind" (Feder song), 2015 * "Blind" (Hercules and Love Affair song), 2008 * "Blind" (Hurts song), 2013 * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ultrashort Pulse
In optics, an ultrashort pulse, also known as an ultrafast event, is an electromagnetic pulse whose time duration is of the order of a picosecond (10−12 second) or less. Such pulses have a broadband optical spectrum, and can be created by mode-locked oscillators. Amplification of ultrashort pulses almost always requires the technique of chirped pulse amplification, in order to avoid damage to the gain medium of the amplifier. They are characterized by a high peak intensity (or more correctly, irradiance) that usually leads to nonlinear interactions in various materials, including air. These processes are studied in the field of nonlinear optics. In the specialized literature, "ultrashort" refers to the femtosecond (fs) and picosecond (ps) range, although such pulses no longer hold the record for the shortest pulses artificially generated. Indeed, x-ray pulses with durations on the attosecond time scale have been reported. The 1999 Nobel Prize in Chemistry was awarded ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frequency-resolved Optical Gating
Frequency-resolved optical gating (FROG) is a general method for measuring the spectral phase of ultrashort laser pulses, which range from sub femtosecond to about a nanosecond in length. Invented in 1991 by Rick Trebino and Daniel J. Kane, FROG was the first technique to solve this problem, which is difficult because, ordinarily, to measure an event in time, a shorter event is required with which to measure it. For example, to measure a soap bubble popping requires a strobe light with a shorter duration to freeze the action. Because ultrashort laser pulses are the shortest events ever created, before FROG, it was thought by many that their complete measurement in time was not possible. FROG, however, solved the problem by measuring an "auto-spectrogram" of the pulse, in which the pulse gates itself in a nonlinear-optical medium and the resulting gated piece of the pulse is then spectrally resolved as a function of the delay between the two pulses. Retrieval of the pulse from its ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GRENOUILLE
Grating-eliminated no-nonsense observation of ultrafast incident laser light e-fields (GRENOUILLE) is an ultrashort pulse measurement technique based on frequency-resolved optical gating (FROG). The acronym was chosen because of the technique's relationship to FROG; ''grenouille'' is French for ''frog''. Theory Because most FROG techniques have an autocorrelator, they also have the sensitive alignment issues that come with it. In addition, most FROGs use a thin second-harmonic generation (SHG) crystal and a spectrometer, adding signal strength requirements as well as additional alignment issues. GRENOUILLE is a simple device based on the SHG FROG, replacing the beam splitter, delay line and beam recombination components of the autocorrelator with a prism, and replacing the spectrometer and thin SHG crystal combination with a thick SHG crystal. The effect of these replacements is to eliminate all sensitive alignment parameters while increasing the signal strength. These changes als ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blind Deconvolution
In electrical engineering and applied mathematics, blind deconvolution is deconvolution without explicit knowledge of the impulse response function used in the convolution. This is usually achieved by making appropriate assumptions of the input to estimate the impulse response by analyzing the output. Blind deconvolution is not solvable without making assumptions on input and impulse response. Most of the algorithms to solve this problem are based on assumption that both input and impulse response live in respective known subspaces. However, blind deconvolution remains a very challenging non-convex optimization problem even with this assumption. In image processing In image processing, blind deconvolution is a deconvolution technique that permits recovery of the target scene from a single or set of "blurred" images in the presence of a poorly determined or unknown point spread function (PSF). Regular linear and non-linear deconvolution techniques utilize a known PSF. For blind ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Double Blind FROG Schematic
A double is a look-alike or doppelgänger; one person or being that resembles another. Double, The Double or Dubble may also refer to: Film and television * Double (filmmaking), someone who substitutes for the credited actor of a character * ''The Double'' (1934 film), a German crime comedy film * ''The Double'' (1971 film), an Italian film * ''The Double'' (2011 film), a spy thriller film * ''The Double'' (2013 film), a film based on the Dostoevsky novella * '' Kamen Rider Double'', a 2009–10 Japanese television series ** Kamen Rider Double (character), the protagonist in a Japanese television series of the same name Food and drink * Doppio, a double shot of espresso * Dubbel, a strong Belgian Trappist beer or, more generally, a strong brown ale * A drink order of two shots of hard liquor in one glass * A "double decker", a hamburger with two patties in a single bun Games * Double, action in games whereby a competitor raises the stakes ** , in contract bridge ** Doubl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nonlinear Optics
Nonlinear optics (NLO) is the branch of optics that describes the behaviour of light in ''nonlinear media'', that is, media in which the polarization density P responds non-linearly to the electric field E of the light. The non-linearity is typically observed only at very high light intensities (when the electric field of the light is >108 V/m and thus comparable to the atomic electric field of ~1011 V/m) such as those provided by lasers. Above the Schwinger limit, the vacuum itself is expected to become nonlinear. In nonlinear optics, the superposition principle no longer holds. History The first nonlinear optical effect to be predicted was two-photon absorption, by Maria Goeppert Mayer for her PhD in 1931, but it remained an unexplored theoretical curiosity until 1961 and the almost simultaneous observation of two-photon absorption at Bell Labs and the discovery of second-harmonic generation by Peter Franken ''et al.'' at University of Michigan, both shortly after the constru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lasers
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The word "laser" is an acronym for "light amplification by stimulated emission of radiation". The first laser was built in 1960 by Theodore H. Maiman at Hughes Research Laboratories, based on theoretical work by Charles Hard Townes and Arthur Leonard Schawlow. A laser differs from other sources of light in that it emits light which is coherence (physics), ''coherent''. Spatial coherence allows a laser to be focused to a tight spot, enabling applications such as laser cutting and Photolithography#Light sources, lithography. Spatial coherence also allows a laser beam to stay narrow over great distances (collimated light, collimation), enabling applications such as laser pointers and lidar (light detection and ranging). Lasers can also have high temporal coherence, which allows them to emit light with a very narrow frequency spectrum, spectr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
