# Homework Help: Laser pulse calculation - a quick bit of help appreciated

1. Jan 7, 2006

### T7

Hi,

a. A free-running, flashlamp-pumped Nd:YAG laser produced pulses having a duration of 500 microseconds at a repetition frequency of l00Hz. Deduce the pulse power in this type of operation if the average power of the laser is 5W. (100W)​

b. This laser is then Q-switched and the average power is reduced to 4W. Deduce the peak power of the Q-switched power (2MW)​

I'm sure this is simple, but I don't seem to be getting the answer I'm supposed to. Anyone care to show how it ought to be done?

Cheers.

T7

Last edited: Jan 7, 2006
2. Jan 7, 2006

### Mattara

Can you show us how far you have come in your calculations?

3. Jan 7, 2006

### T7

Yup. I think I've just realised what I was doing wrong as far as part a is concerned.

Let Pa denote average power
Let Pp denote power of one pulse
Let Ep denote energy of one pulse
Let t denote time of one pulse

If Pa = 5W, and f = 100Hz, then

Ep x 100 = 5 => Ep = 0.05
Pp = Ep / t = 0.05 / (500 x 10^-6) = 100W

I think that's right. (Hope so).

Last edited: Jan 7, 2006
4. Jan 7, 2006

### T7

I would apply a similar sort of working to the second part. I don't see how it can be done without more information.