Question

The YAG Laser in the Laser Laboratory is a pulsed laser that emits infrared light of wavelength 1064 nm at a frequency of 10 Hz. Suppose that one pulse from the YAG Laser has an average energy of 1.2 J and lasts for a time of 14 ns. What is the energy (in eV) of one photon of this laser light?

How many photons are emitted in one pulse from the YAG Laser?

What is the power output (in W) during one 14 ns pulse of this laser light? This is referred to as the Peak Power of the laser.

What is the Average Power output (in W) during one full second of laser operation?

What is the major advantage to using a pulsed laser?

Answer 1

Energy of a photon = h c / wavelength

= (1240 eV-nm) / (1064 nm)

= 1.16 eV ....Ans

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Energy of 1 pulse = 1.2 J

n = (1.2 J) / (1.16 x 1.6 x 10^-19 J)

n = 6.43 x 10^18 photons

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P = E / t = (1.2 J ) / (14 x 10^-9 s)

P = 85.7 x 10^6 W

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frequency is 10 Hz  

10 times in a sec.

so total energy in 1 sec = (1.2 x 1) = 1.2 J/s

average power output = 1.2 W  

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