Ultrafast High Power Laser
ID: 1676084 • Letter: U
Question
One of the highest power lasers in the world sits on a table in theGeneral Research Lab Building at Colorado of Donkeys. It emitspulses that last approximately 23.0 fs(10-15 seconds), and contain 95.0 mJ of energy.What is the average rate atwhich energy is delivered by a single pulse? "Rate" refers to powerin this case.
What is the physicallength of this pulse?
When the beam exitsthe laser, it is approximately 30 mm in diameter. Molecules beginto ionize when applied electric fields reach approximately 8.68E+9V/m. To what diameter must the beam be focused to reach thiselectric field strength?
What is the average rate atwhich energy is delivered by a single pulse? "Rate" refers to powerin this case.
What is the physicallength of this pulse?
When the beam exitsthe laser, it is approximately 30 mm in diameter. Molecules beginto ionize when applied electric fields reach approximately 8.68E+9V/m. To what diameter must the beam be focused to reach thiselectric field strength?
Explanation / Answer
P = E / t = 9.5 * 10E-2 / 2.3 * 10E-14 = 4.13 *10E12 W power / pulse L = c t = 3 * 10E8 * 2.3 * 10E-14 = 6.9 * 10E-6m length of pulse V = A L = * .0152 * 6.9 * 10E-6= 4.88 * 10E-9 m3 U = 9.5 * 10E-2 / 4.88 * 10E-9 = 1.95 * 10E7 J /m3 energy density in a single pulse U = 1/2 0 E2 energystored in electric field E = (2 U / 0) = (3.9 * 10E7 /8.85 * 10E-12) = 2.10 * 10E9 V / m So the area of the beam would have to decrease by 2.10 / 8.68= .24 Halving the diameter of the beam would produce 4 times theelectric field strength since V ˜ to r2Related Questions
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