about laboratory for attosecond physics

— Ferenc Krausz —

Mission statement

Life on Earth is based on a natural symbiosis of electrons and light: the motion of electrons creates light that supplies life-giving energy for our globe and transforms light into biological energy and signals, which in turn allow plants to grow and animals and humans to see. Beyond being vital for life, these motions can also be fatal, upon modifying molecular structures and hence affecting biological function. At the most fundamental level, electrons maintain and end life in biological systems, and serve and save lives in technical devices.

The force fields of laser light, if precisely controlled, permit steering and observing electronic motions and vice versa, controlled electronic motions enable the generation and probing of such fields, extending the symbiosis of light and electrons from nature to technology. These control capabilities open novel routes to extending the repertoire with which physics is able to advance technology and assist medicine.

With controlled forces of light – from terahertz (infrared) to petahertz (ultraviolet) frequencies – we induce, control and probe electric current at atomic scales in space and time with the aim to explore the ultimate frontiers of electron-based signal processing and identify viable routes towards those frontiers.

In a similar way, we induce, control and probe structural and electronic dynamics of molecules of living systems with the aim to acquire and identify fingerprints of their abnormal physiologies. We focus on evaluating the ability of field-resolved-spectroscopic fingerprinting to detect and classify cancer at the earliest stages of its development and monitor its response to therapy.

We feel obliged to disseminate the knowledge and expertise we acquire and are glad to share our findings and provide advice and technical assistance to researchers of any public institution of the world committed to serving mankind by advancing science, technology or medicine. Do get in touch if you are interested!

Our Logo

Attosecond-resolution photograph:
This attosecond-resolution photograph taken in 2004 has been chosen to represent the joint Ludwig Maximilians University (LMU)-Max Planck Institute of Quantum Optics (MPQ) Laboratory for Attosecond Physics (LAP), established in the same year. It reveals a snapshot of a wave of red laser light, recorded with attosecond flashes of light, establishing attosecond metrology. An attosecond is a billionth of a billionth of a second. (The background image displays the heart of the experimental apparatus along with the laser and the ultraviolet beams used for this measurement.)

Our Milestones

  • 2000: Atomic motions deciphered

    2000: Atomic motions deciphered

    Femtochemistry comes of age1. Molecular dynamics is routinely captured via femtosecond light pulses.

    When scientists started to „take pictures“ of the movements of atoms in molecules during chemical reactions at the end of the 1980s, this had little to do with conventional photography. The basic principle, however, remained the same: A short exposure time was needed to »freezethe« dynamics under scrutiny and display changes of the microscopic states of matter in a series of snapshots taken at different instant during the evolution of the system. The atomic composition and/or structure of molecules can change within femtoseconds, i.e. within millionths of a billionth of a second. The required ultrashort exposure time was provided by femtosecond laser pulses.

    The 1999 Nobel Prize in Chemistry honoured the pioneering contributions of Prof. Ahmed Zewail from CALTECH to establishing femtochemistry, permitting the observation of changes in the atomic structure and/or composition of molecules in real time. In spite of these breathtaking advances, several mysteries remained unresolved.

    How do the electrons move prior to changes in atomic structure and how does initial electron dynamics influence the fate of the molecule? How does electron-nuclear coupling affect reaction pathways? Answers to them called for even faster techniques, reaching out into the attosecond domain, the characteristic time scale of electronic motions at the atomic scale.

  • 2001: A new dimension of time

    2001: A new dimension of time

    Scientists – for the first time – succeed in producing and measuring light flashes which last less than one femtosecond in an experiment1 what, according to Yaron Silberberg (Weizmann Institute), »might be the dawn of attophysics — the study of dynamics on timescales fast enough to follow electronic motion within atoms«2.

    Independently, researchers in Paris demonstrated trains of such pulses, following upon each other every half cycle of the laser field used for their generation and measurement3. In both cases, the electric field of near-infrared (NIR) laser pulses were used for both the generation and measurement of XUV light varying on an attosecond scale. In the generation process, the NIR field tunnel ionized atoms on its wave crests and the detached electron returning to the vicinity of its parent ion emitted a burst of extreme ultraviolet (XUV) light. The process was repeated each half cycle of the driving laser light, resulting in a train of sub-femtosecond bursts in the experiment of Paul et al using multi-cycle driving fields3. By contrast, in the Vienna experiment1 confining the ionization largely to the central field cycle along with careful high-pass filtering of the emitted XUV light isolated a single burst from the train emitted in the experiment of Paul et al. This lead to the production of a single sub-femtosecond pulse by each near-infrared laser pulse. These tools opened the door towards the first attosecond real-time observation of electron dynamics.

  • 2002: Diving deep into the atom

    2002: Diving deep into the atom

    For the first time, real-time access to electron processes deep inside the atom is obtained in a study1 that, according to Louis DiMauro (Brookhaven National Laboratory), »…announce the beginning of a new era…. We are entering a new realm of hyperfast measurements; the age of attophysics has begun.«2

    For more than a decade it has already been possible to explore the movements of atoms and molecules during chemical reactions by means of femtosecond laser pulses. However, the considerably lighter electrons are much quicker: Deep inside atoms, a vacant quantum state, i.e. a »hole«, may be filled by an electron at the »margin« of an atom within a few hundred to several thousand attoseconds. With the help of 650-attosecond extreme ultraviolet flashes

    X-ray flashes it is now possible to observe such a transition between two quantum states nearby the atomic nucleus directly. As the graphical artist of the New York Times visualized, the attosecond flash knocks out an electron from an inner shell of an atom (in this case: krypton atom). Electrons at the »margin« of the atom try to fill up the «hole« as quickly as possible. During that process, energy is released through the emission of a second electron, an Auger electron, as it is called. The emission time of the Auger electron is captured by the field of the infrared laser pulse previously used for the generation of the attosecond burst and hence being perfectly synchronized to it. These tools have opened the door for gaining direct, time-resolved insight into the way electrons move in an excited atom.

  • 2003: Control of light waves

    2003: Control of light waves

    Laser pulses with a reproducible waveform and hence perfectly controlled temporal evolution of their electric field on an attosecond scale are generated, a feat which, according to Philip H. Bucksbaum (University of Michigan, Ann Arbor), »…marks the beginning of the era of ‘attophysics’ — the study of physical processes on the attosecond timescale.«1 They contain only a few wave oscillations.

    Capitalizing on the frequency-comb technique invented by Prof. Theodor Hänsch (Max-Planck-Institute of Quantum Optics), which allowes precise control of the frequencies of the phase-locked modes of a femtosecond laser oscillator, researchers at the Vienna University of Technology, in collaboration with the group of Prof. Hänsch, produced a train of intense few-cycle laser pulses with precisely-controlled oscillations of their electric and magnetic fields.

    These controlled fields imply controlled forces acting upon electrons, allowing, for the first time the control of electronic motions in atomic systems on an attosecond time scale. The first spectacular consequences of this newly-emerged capability are the generation of isolated attosecond pulses with precisely controlled characteristics and the measurement of the electric field of light, briefly: precision attosecond metrology.

  • 2004: Precision attosecond metrology

    2004: Precision attosecond metrology

    The controlled electric force field of waveform-controlled light generates reproducible attosecond pulses and a streak »camera« operated with these controlled fields accurately characterizes these flashes1 and uses them for measuring oscillating light fields2.

    The use of attosecond flashes and controlled few-cycle laser fields for capturing hyperfast electronic motions requires their accurate characterization. To this end, the flashes knock out electrons from atoms, which – depending on their moment of release – are accelerated or decelerated by the controlled electric field of the few-cycle pulse that previously generated the attosecond pulse and is beamed in simultaneously. As a result, the temporal profile of the attosecond photoemission is mapped to a final momentum distribution recorded in the light-field-driven streak camera. Recording these »streak images« as a function of delay between the attosecond pulse and the streaking laser field yields what has been referred to as the attosecond streaking spectrogram. This allows retrieval of both the electric field waveform of the laser pulse and the intensity envelope and frequency sweep of the attosecond pulse inducing the photoemission, which, meanwhile, is routinely produced with sub-100-as duration3.

    Ever since their first demonstration, controlled few-cycle laser fields and reproducible isolated attosecond pulses constitute the main tools for attosecond measurements with light-field-driven streaking serving as a gold standard for precision attosecond metrology.

  • 2007: On the scent of electrons

    2007: On the scent of electrons

    Electron tunnelling in atoms1 and Angstrom-scale electric charge transport in solids2 can now be scrutinized directly in the time domain.

    With techniques for the reproducible generation and reliable measurement of attosecond pulses and controlled near-single-cycle laser fields in place, widespread applications to real-time observation and control of electronic processes in atomic, molecular and solid-state systems could begin. The temporal dynamics of fundamental processes such as electron tunnelling during strong-laser-field-induced ionization of atoms1 and Angstrom-scale electric charge transport through atomic layers of solids2 can now be tracked directly in the time domain.

  • 2010: Real time access to electron motion

    2010: Real time access to electron motion

    Attosecond-tools provide realtime access to electron motion.

    Whereas the former study provides fundamental insight into strong-field-atom interactions, the latter capability will be beneficial to advancing electronics towards its ultimate speed limits, to light-wave frequencies. Meanwhile, these tools also provide real-time access to valence electron motion inside atoms (Nature, August 5, 2010) as well as molecules.

    Moreover, precision measurement of the timing of photoemission with an precision of less than 10 attoseconds now reveals the role of electron correlations in this fundamental process (Science, June 25, 2010).

  • 2011: Tailor-made light waves

    2011: Tailor-made light waves

    Synthesized waveforms of lightpulses consist of less than a full oscilation.

    In order to control electrons, the waveform of light must be tailored within one oscillation period. That requires »ultra white« laser light, which involves not only all colours of the visible spectrum, but also infrared and ultraviolet waves, as well as a tool which combines these waves oscillating at different speeds. In 2011, LAP researchers developed a »light wave synthesizer«, as it is called, which allows the control of the oscillation of light with state-of-the-art precision. Using this technology, the scientists succeeded in creating completely new waveforms in the pulses. They may now consist of less than a full oscillation and hence last only around two femtoseconds. With that the physicists generated the shortest flashes of visible light observed to this day. It is now possible to control the temporal evolution of the force exerted by light on the attosecond scale. Thus, the technology promises, for the first time, the precise control of electron movements. Since all the energy of the electromagnetic field clusters in a tiny time window, the new tool allows for a stimulation of processes within one femtosecond and opens the door to the attosecond pump-probe experiments (Science, October 14, 2011).

Cover stories

  • Signal control with light frequencies

    Signal control with light frequencies

    Light waves have the potential to boost the efficiency of conventional electronics by a factor of 100,000. In a review article that appears in »Nature Photonics« on March 14th, Prof. Ferenc Krausz of the Laboratory for Attosecond Physics (LAP) at the Max-Planck-Institut für Quantenoptik and the Ludwig-Maximilians-Universität München and his co-author Prof. Mark Stockman of Georgia State University (GSU) in Atlanta describe how this vision may one day come true. In their scenario, one would exploit the electric field of laser light to control the flow of electrons in dielectric materials, which, in turn, may modulate transmitted light and switch current in electronic circuits at light frequencies. Visible light oscillates at frequencies of about 1015 cycles per second, opening the possibility of switching light or electric current at rates in this range. And since both signals can also carry information, innovative optoelectronic technologies would enable a corresponding increase in the speed of data processing, opening a new era in information technology. The authors review the novel tools and techniques of attosecond technology, which may play a crucial role in making the above advances actually happen.

  • Ultraschneller Tauchgang in die Atome

    Ultraschneller Tauchgang in die Atome

    In 2001, when scientists around Prof. Ferenc Krausz for the first time succeeded to produce light flashes which only lasted attoseconds, a new era was ushered in natural sciences. Attosecond physics was born. Now, it should be possible to observe electrons and hence wrench the microcosm one of its most closely guarded secrets. In his book Ultraschneller Tauchgang in die Atome, Thorsten Naeser, head of press and public relations within the cluster of excellence Munich-Centre for Advanced Photonics (MAP), talks about the development of attosecond physics. Building upon the basics of quantum mechanics, laser physics and chronophotography, Thorsten Naeser describes how electrons can be captured in images today: with light flashes which last only a few billionth of a billionth second. Thorsten Naeser also picturesquely describes numerous results attosecond physics has brought to this day and where the road of exploring quantum particles may lead.

  • A laser-driven nanosecond proton source for radiobiological studies

    A laser-driven nanosecond proton source for radiobiological studies

    The fast paced field of ultrafast nanoscience exploits both ultrafast optics and nanostructuring techniques to explore new phenomena, ranging from plasmonic coupling of light and matter to attosecond physics. The special issue edited by Peter Hommelhoff, Matthias Kling and Mark Stockman, highlights the recent rapid progress in the field. Ultrafast phenomena described in the contributed articles include linear and non-linear effects over a wide range of applications including one- and multidimensional (spatially resolved) spectroscopies, time-resolved measurements of localized and propagating surface plasmons, the dynamics of nanostructures in ultrashort and ultrastrong fields, the ultrafast emission of electrons, the coherent generation of light including high-harmonic generation, and nanoscale devices, which contribute to the development of ultrafast nanoscale electronics.

  • A laser-driven nanosecond proton source for radiobiological studies

    A laser-driven nanosecond proton source for radiobiological studies

    Ion beams are relevant for radiobiological studies and for tumor therapy. In contrast to conventional accelerators, laser-driven ion acceleration offers a potentially more compact and cost-effective means of delivering ions for radiotherapy. Here, we show that by combining advanced acceleration using nanometer thin targets and beam transport, truly nanosecond quasi-monoenergetic proton bunches can be generated with a table-top laser system, delivering single shot doses up to 7Gy to living cells. Although in their infancy, laser-ion accelerators allow studying fast radiobiological processes as demonstrated here by measurements of the relative biological effectiveness of nanosecond proton bunches in human tumor cells.

  • Invited Article: Attosecond photonics: Synthesis and control of light transients

    Invited Article: Attosecond photonics: Synthesis and control of light transients

    Ultimate control over light entails the capability of crafting its field waveform. Here, we detail the technological advances that have recently permitted the synthesis of light transients confinable to less than a single oscillation of its carrier wave and the precise attosecond tailoring of their fields. Our work opens the door to light field based control of electrons on the atomic, molecular, and mesoscopic scales.

  • Elektronen unter Kontrolle

    Elektronen unter Kontrolle

    Mithilfe ultrakurzer Lichtimpulse lassen sich Elektronen in Molekülen und Nanostrukturen auf Zeitskalen von Attosekunden steuern und beobachten.

  • Attosecond Physics – the first decade On the route to tiny time scales

    Attosecond Physics – the first decade On the route to tiny time scales

    Deep inside matter, our ideas of time lose their validity. Light flashes which last only a few millionths to billionths of a billionth second snatch from the microcosm its closely guarded secrets: Electron movements become visible. Quantum phenomena can be examined in real time. The control of elementary particles comes within reach. Responsible for all that is the young science of attosecond physics, »born« in 2001, when Prof. Ferenc Krausz succeeded in producing and measuring light flashes which last less than one femtosecond. Krausz founded the Laboratory for Attosecond Physics (LAP) which is located at the Max Planck Institute for Quantum Optics in Garching, Germany. Here is the history of how Attosecond Physics has been developed in LAP over the last ten years.

  • Sub-femtosecond sculpted light transients probe the atom

    Sub-femtosecond sculpted light transients probe the atom

    Attosecond (as) photonics is a rapidly developing tool to help scientists study the behavior of matter and energy at this extraordinarily short time scale. Now, the group that first created 80-as light pulses has reached a new milestone: the shaping and attosecond sampling of »light transients« within a 2.4 fs time span over a 0.3–0.9 PHz frequency range. Light transients are nonrepeating sculpted waveforms that are completely confined to a single cycle, or at most a few cycles.

  • A Decade in Attosecond Science

    A Decade in Attosecond Science

    The year 2011 marks the 10th anniversary of an important advance in ultrafast laser pulses:For the first time, laser physicists were able to breake the femtosecond barrier to create attosecond Pulses – the shortest light pulses ever generated in the laboratory.

  • Real-time observation of valence electron motion

    Real-time observation of valence electron motion

    A sequence of snapshots showing the oscillatory motion of a valence electron inside an atomic ion, as reconstructed from attosecond measurements

  • Tripling in neon produces 2.8 fs deep-UV pulses

    Tripling in neon produces 2.8 fs deep-UV pulses

    Femtosecond and attosecond light pulses are now allowing scientists to deeply explore the workings of atoms, molecules and nanoparticles. For example few-cycle deep ultraviolet pulses fired at molecules can manipulate valence-shell electrons, preparing the molecules for high-resolution study via attosecond spectroscopy.

  • Delay in photoemission

    Delay in photoemission

    Three-dimensional representation of the emission of electrons from a neon atom upon absorption of a photon from an attosecond extreme ultraviolet pulse. The orange surface plot represents the resulting electron energy distribution, which, when probed by an ultrashort light wave (yellow line), reveals an unexpected time delay between the emission of electrons from different atomic orbitals.

  • In Pursuit of the Briefest Beat

    In Pursuit of the Briefest Beat

    Attosecond pulses of light could open electrons’ fast-paced world. Science writer Charles Petit gives insight into attosecond physics.

  • Optics made to measure

    Optics made to measure

    Researchers in Germany have set up a company to manufacture custom-made optics for ultrafast applications. Nadya Anscombe finds out about the company’s products and its plans for the future.

  • Europe leads the way in attosecond research

    Europe leads the way in attosecond research

    Breaking the 100 as barrier and making the first movie of electron motion are just two recent milestones achieved by European researchers. Nadya Anscombe talks to key players in the attosecond community to see what the future holds.

  • Attosecond pulses: Light to reveal electrons interacting within atoms

    Attosecond pulses: Light to reveal electrons interacting within atoms

    By carefully controlling the waveform of an ultrafast laser pulse and sending it through a jet of neon gas, briefly ionizing it, researchers at the Max-Planck-Institut für Quantenoptik (MPQ; Garching, Germany), the Ludwig-Maxmilians-Universität (also in Garching), and the Lawrence Berkeley National Laboratory (Berkeley, CA) have created the shortest light pulse yet only 80 attoseconds (as) in duration. Such well-controlled photoionization will result in new science, for example by allowing direct observation of quantum-electronic correlations.

  • Watching what happens during attoseconds in solids

    Watching what happens during attoseconds in solids

    During attosecond-scale phenomena may enable electronics 100.000 times faster than todays devices.

  • Attosecond pulses probe electronics

    Attosecond pulses probe electronics

    Understanding the motions of electrons inside solids is the basis for future technological development in computing speed, ultrahigh-speed communications, and remote surgery, among other possibilities. Such advances depend on detection and measurement of the atomic-scale motion of electrons, which take mere attoseconds to travel from atom to atom in a solid.

  • Attosecond spectroscopy in condensed matter

    Attosecond spectroscopy in condensed matter

    Comprehensive knowledge of the dynamic behaviour of electrons in condensed-matter systems is pertinent to the development of many modern technologies, such as semiconductor and molecular electronics, optoelectronics, information processing and photovoltaics. Yet it remains challenging to probe electronic processes, many of which take place in the attosecond (1 as = 10−18 s) regime. In contrast, atomic motion occurs on the femtosecond (1 fs = 10−15s) timescale and has been mapped in solids in real time using femtosecond X-ray sources. Here we extend the attosecond techniques previously used to study isolated atoms in the gas phase to observe electron motion in condensed-matter systems and on surfaces in real time. We demonstrate our ability to obtain direct time-domain access to charge dynamics with attosecond resolution by probing photoelectron emission from single-crystal tungsten.

  • Attosecond Control and Measurement: Lightwave Electronics

    Attosecond Control and Measurement: Lightwave Electronics

    Electrons emit light, carry electric current, and bind atoms together to form molecules. Insight into and control of their atomic-scale motion are the key to understanding the functioning of biological systems, developing efficient sources of x-ray light, and speeding up electronics. Capturing and steering this electron motion require attosecond resolution and control, respectively (1 attosecond = 10−18 seconds). A recent revolution in technology has afforded these capabilities: Controlled light waves can steer electrons inside and around atoms, arking the birth of lightwave electronics. Isolated attosecond pulses, well reproduced and fully characterized, demonstrate the power of the new technology. Controlled few-cycle light waves and synchronized attosecond pulses constitute its key tools. We review the current state of lightwave electronics and highlight some future directions.

  • Die ganze Physik zum 21. Jahrhundert

    Die ganze Physik zum 21. Jahrhundert

    Editor D. Meschede released the 23. Volume of the encyclopedia Gerthsen Physik.

  • Welcome to attoworld

    Welcome to attoworld

    The dial on your kitchen scales spins when a virus lands. The clock on the wall has gone berserk, ticking every billionth of a billionth of a second. Your camera flashes so fast that it captures single molecules in freeze-frame. Prepare to enter attoworld, the ultra-small realm so foreign that no one quite knows whats going on. Hazel Muir zooms in.

  • Ultrashort Laser Pulses Beget Even Shorter Bursts in the Extreme Ultraviolet

    Ultrashort Laser Pulses Beget Even Shorter Bursts in the Extreme Ultraviolet

    The attophysics frontier is about to expand, thanks to the newly won ability to control the phase of amplified laser pulses.

  • Time-resolved atomic inner-shell spectroscopy

    Time-resolved atomic inner-shell spectroscopy

    The characteristic time constants of the relaxation dynamics of core-excited atoms have hitherto been inferred from the linewidths of electronic transitions measured by continuous-wave extreme ultraviolet or X-ray spectroscopy. Here we demonstrate that a laser-based sampling system, consisting of a few-femtosecond visible light pulse and a synchronized sub-femtosecond soft X-ray pulse, allows us to trace these dynamics directly in the time domain with attosecond resolution. We have measured a lifetime of 7.9+1.0−0,9 fs of M-shell vacancies of krypton in such a pumpprobe experiment.

  • Optical pulses reach attosecond length

    Optical pulses reach attosecond length

    In the world of ultrashort optical pulses, the femtosecond (fs) has been superseded by the attosecond (as, or 10−18 s). An international collaboration of ten scientists claims to have generated and detected isolated soft x-ray pulses of 650-as duration. Scientists at the Vienna University of Technology, Austria, along with others at the National Research Centre (Ottawa, Canada) and the University of Bielefeld, Germany, have developed experimental tools and techniques that could enable attosecond-resolution spectroscopy of bound electron dynamics in atoms and molecules.

  • Intense few-cycle laser fields: frontiers of nonlinear optics

    Intense few-cycle laser fields: frontiers of nonlinear optics

    The rise time of intense radiation determines the maximum field strength atoms can be exposed to before their polarizability dramatically drops due to the detachment of an outer electron. Recent progress in ultrafast optics has allowed the generation of ultraintense light pulses comprising merely a few field oscillation cycles. The arising intensity gradient allows electrons to survive in their bound atomic state up to external field strengths many times higher than the binding Coulomb field and gives rise to ionization rates comparable to the light frequency, resulting in a significant extension of the frontiers of nonlinear optics and (nonrelativistic) high-field physics. Implications include the generation of coherent harmonic radiation up to kiloelectronvolt photon energies and control of the atomic dipole moment on a subfemtosecond time scale. This review presents the landmarks of the 30-odd-year evolution of ultrashort-pulse laser physics and technology culminating in the generation of intense few-cycle light pulses and discusses the impact of these pulses on high-field physics.

  • Extreme nonlinear optics. Exposing matter to a few periods of light

    Extreme nonlinear optics. Exposing matter to a few periods of light

    Intense light pulses in the single-cycle regime have opened up new avenues in linear optics. These, along with expected impacts on other areas of science and technology, are discussed.

  • Chirped dielectric mirrors improve Ti:sapphire lasers

    Chirped dielectric mirrors improve Ti:sapphire lasers

    High-quality seed pulses from mirror-dispersion-controlled Ti:sapphire system allow chirped pulse amplification without a pulse stretcher.

  • Faster than the speed of light

    Faster than the speed of light

    Quantum mechanics have been with us for over sixty years and has been thoroughly put through its paces both experimentally and theoretically. Yet physicists continue to be haunted by its strange implications virtual particles, antimatter, negative energy, Schrödingers cat. Now it appears there is something else to add to the list: light that travels faster than light.

Progress reports

Do you want to learn more about the Laboratory for Attosecond Physics (LAP), its innovations, and scientific progress? Then, take a look at our latest progress reports.
  • Progress report 2014 — 2016
  • Progress report 2011 — 2013
  • Progress report 2009 — 2010
  • Progress report 2007 — 2008
Please note:
These reports are excerpts from progress reports by Max-Planck-Institute of Quantum Optics (MPQ), concerning its Attosecond Physics Division. For the complete documents, please visit the MPQ website.
  • Interaction between light and electron
    Interaction between light and electron
  • Development of infrared laser technologie
    Development of infrared laser technologie
  • Broadband optical parametric amplifier
    Broadband optical parametric amplifier
  • The inner live of the crypton atom
    The inner live of the crypton atom