Sample interview questions: What are some common techniques for achieving ultrashort laser pulses in the x-ray range?
Sample answer:
Some common techniques for achieving ultrashort laser pulses in the x-ray range include:
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High harmonic generation (HHG): This technique uses intense laser pulses to generate high harmonics of the laser frequency. By focusing these harmonics, it is possible to generate coherent x-ray radiation with pulse durations on the order of tens to hundreds of attoseconds (10^-18 seconds).
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Free-electron lasers (FELs): FELs are based on the principle of accelerating electrons to relativistic velocities and then causing them to emit coherent x-ray radiation through an undulator. FELs can produce very intense and ultrashort x-ray pulses with durations ranging from femtoseconds (10^-15 seconds) down to even attoseconds.
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Optical parametric chirped-pulse amplification (OPCPA): OPCPA is a technique that combines optical parametric amplification and chirped-pulse amplification. It involves using a nonlinear crystal to generate a broadband spectrum from an ultrashort laser pulse, which is then temporally stretched and amplified. By subsequently compressing the pulse, ultrashort x-ray pulses can be obtained.
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Laser-driven plasma accelerators: These accelerators use intense laser pulses to create a plasma wave that can accelerate electrons to relativistic energies. When these accelerate… Read full answer