Question

Problem 3: An Nd:YAG laser operates in a pulsed mode, with an energy of 100mJ (millimoles) per pulse, and a pulse repetition rate of 10Hz. Light can be emitted at 1065 nm, 532 nm, or 355 nm. (a) Each pulse lasts for 1ns, and in between pulses, no light is emitted. What is the instantaneous laser power during each pulse

Answer 1

Given Information:

Energy of laser pulses = E = 100 mJ = 100×10⁻³ Joules

Time = t = 1 ns = 1×10⁻⁹ seconds

Required Information:

Instantaneous power = P = ?

Answer:

$Instantaneous \: Power = 100 \: Mwatt$

Explanation:

The instantaneous power is the power dissipated at any instant of time whereas the average power is the power dissipated over a given time interval.  

The instantaneous laser power during each pulse is given by

$Instantaneous \: Power = \frac{E}{t}$

Where E is the energy of the laser pulses and t is the time that each pulse lasts.

$Instantaneous \: Power = \frac{100\times10^{-3}}{1\times10^{-9}}$

$Instantaneous \: Power = 1\times10^{8} \: watt$

or

$Instantaneous \: Power = 100 \: Mwatt$

Therefore, the instantaneous power of each pulse is 100 Mwatt.