Question
This technique allows the creation of petawatt-intensity laser pulses, which are used to excite plasma waves in wakefield particle accelerators that are small enough to fit on a table. For 10 points each:
[10h] Identify this technique developed by Gerard Mourou and Donna Strickland, in which a pulse generated by Q-switching or mode-locking is stretched in time and then later re-compressed in order to increase its intensity.
ANSWER: chirped-pulse amplification [accept CPA]
[10e] The stretcher grating pair introduces positive chirp, meaning this quantity for the pulse increases in time. The energy of a photon is equal to Planck’s constant times this quantity.
ANSWER: frequency [prompt on f or nu]
[10m] By stretching the pulse first, CPA bypasses a costly roadblock in which catastrophic self-focusing of laser pulses via this effect would destroy laser components. The refractive index depends on the square of the electric field in this nonlinear optical effect.
ANSWER: Kerr effect
<VD, Physics>
Summary
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