Hertel, I. V., I. Shchatsinin, T. Laarmann, N. Zhavoronkov, H.-H. Ritze und C. P. Schulz: 2009, ‘Fragmentation and ionization dynamics of C60 in elliptically polarized femtosecond laser fields’. Phys. Rev. Lett. 102, 023003.

Shchatsinin, I., et al.: 2006, ‘C60 in intense short pulse laser fields down to 9 fs: excitation on time scales below e-e and e-phonon coupling’. J. Chem. Phys. 125, 194320.

EasyFog

We’ll set the scene by imagining some different data scenarios. Think about the simple telegraph set, where one wire carries a signal that is transmitted one zap or quiet space at a time. These zaps travel all the way back and forth as electrons are swapped on the molecular level. At its simplest level, that’s what electricity is.

Gordon, J. P., H. J. Zeiger und C. H. Townes: 1955, ‘Maser - New type of microwave amplifier, frequency standard, and spectrometer’. Phys. Rev. 99, 1264–1274.

World Creator

Laser sind heute aus Wissenschaft, Technik und täglichem Leben nicht mehr wegzudenken. Sie bilden auch eine wesentliche experimentelle Basis für die moderne Atom- und Molekülphysik und natürlich für die optische Physik. Es gibt dazu eine Fülle von Literatur, deren Aufzählung viel Platz beanspruchen würde. Beispielhaft sei hier nur Siegman (1986) als umfangreicher Klassiker genannt (letzte Druckfehlerkorrektur März 2009, Homepage des Autors ), sowie eine etwas spezialisiertere Monographie jüngeren Datums (Hodgson und Weber, 2005) als Einstieg für vertieftes Studium. In diesem Abschnitt wollen wir lediglich einige wenige Grundbegriffe und Definitionen einführen, von denen in diesem Lehrbuch an anderer Stelle Gebrauch gemacht wird.

Even with cutting-edge transfer of data, like in massive fiber optic trunks that connect entire cities or countries, bouncing light particles are what power the entire technology. These technologies shed photons, so finding ways to cut down on loss is a huge industry unto itself. The more data we send, the more the tiny losses add up to real amounts of data lost.

Brushify

Now, imagine a computer network where files are passed back and forth to and from a server or among different workstations. The passage of these files appears to be lightning-fast, but in reality, different pieces are being passed back and forth one at a time. The algorithms that manage it even have “collision detection” to make sure that less data is lost when pieces collide in the cables.

In new research, scientists from the National Institute of Standards and Technology (NIST) and quantum workgroups at Griffith University in Brisbane, Australia, suggest that quantum data transfer could blow our minds. Their research, which experiments with capturing and recovering stray photons during data transfers, appears in Nature Communications.

To study loss, the scientists first set up an experiment where a non-important photon was bounced into a position where it would intentionally be lost in the interference noise. To control the loss, they first applied a device called a noiseless linear amplifier. When it works, this device seems to “catch” the errant photon, return it to the quantum state, and zoom it back into the healthy portion of the data.

Shchatsinin, I., H.-H. Ritze, C. P. Schulz und I. V. Hertel: 2009, ‘Multiphoton excitation and ionization by elliptically polarized, intense short laser pulses: Recognizing multielectron dynamics and doorway states in C60 vs Xe’. Phys. Rev. A 79, 053414.

Voxel Plugin

ErrantWorlds

Here’s the other thing about continuous or linear flow of information: there is loss. Even in computer networks, packets of data do sometimes collide or drop, and get lost. And in a massive local fiber optic network, for example, the light bounces around inside the fiber—with some inevitable loss from the nature of light itself. “Loss-induced noise, e.g., from scattering and diffraction, is inevitable in long-distance information transfer,” the researchers write.

Hankin, S. M., D. M. Villeneuve, P. B. Corkum und D. M. Rayner: 2001, ‘Intense-field laser ionization rates in atoms and molecules’. Phys. Rev. A 6401, 013405.

Lindner, F., G. G. Paulus, H. Walther, A. Baltuska, E. Goulielmakis, M. Lezius und F. Krausz: 2004, ‘Gouy phase shift for few-cycle laser pulses’. Phys. Rev. Lett. 92, 113001.

One of the biggest questions of our modern age is how best to transmit enormous amounts of data over larger and larger spaces. Now, quantum theorists suggest that “teleportation”—something previously dreamed of by Star Trek and Willy Wonka—could be the quantum secret to unlock truly lossless data transmission.

“A working long-distance quantum communication channel needs a mechanism to reduce this information loss, which is exactly what we did in our experiment,” researcher Sergei Slussarenko says in a statement. “Our work implements a so-called quantum relay, a key ingredient of this long-distance communication network.”

Next, the researchers want to test this method for long-distance quantum cryptography. After that, they can start dreaming of a truly secure global quantum network.

Hänsch, T. W.: 2005, ‘Nobel lecture: Passion for precision’. http://nobelprize.org/nobel_prizes/physics/laureates/2005/hansch-lecture.html.

Gaea

Caroline Delbert is a writer, avid reader, and contributing editor at Pop Mech. She's also an enthusiast of just about everything. Her favorite topics include nuclear energy, cosmology, math of everyday things, and the philosophy of it all.

Schmidt, A., et al.: 2010, ‘Diode-pumped mode-locked Yb:LuScO3 single crystal laser with 74 fs pulse duration’. Opt. Lett. 35, 511–513.

Both of these scenarios involve passing data. They seem very different in complexity, but both also represent a simple paradigm: continuous flow. In these situations, data pours in one direction or the other like water from a pitcher. Sometimes it alternates, but the flow is still continuous through the pipes.

Javan, A., W. R. Bennett und D. R. Herriott: 1961, ‘Population inversion and continuous optical maser oscillation in a gas discharge containing a He-Ne mixture’. Phys. Rev. Lett. 6, 106–110.

Steinmeyer, G.: 2010, ‘Interferometrische Bestimmung der Autokorrelationsfunktion eines sub 20 fs Laser Impulses’. Berlin: Max-Born-Institut

Licht und Photonen spielen bei allen spektroskopischen Methoden eine zentrale Rolle. Wir haben ihre Verfügbarkeit und Manipulierbarkeit bislang stillschweigend vorausgesetzt und Licht implizite als ebene, elektromagnetische Wellen verstanden. Räumliche und zeitliche Abhängigkeiten spielten dabei eine untergeordnete Rolle. Diese Beschränkung wollen wir jetzt aufheben.

Hertel, I.V., Schulz, CP. (2010). Laser, Licht und Kohärenz. In: Atome, Moleküle und optische Physik 2. Springer-Lehrbuch. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-11973-6_3