# Laser pulse energy

1. Apr 6, 2012

### predrummer

Hi to you all,

I have a quick question about laser pulse energy.

For Q-switching solid state laser source, can you change the energy of a laser pulse without changing the wavelength? If so, how?

Thanks so much...

2. Apr 7, 2012

### Staff: Mentor

I'm not sure what you are asking. You should be able to increase or decrease the energy in the pulse to a varying degree that is within the operational range of the laser. Did you have a more specific question?

3. Apr 7, 2012

### predrummer

Unfortunately, my knowledge in this area is not deep. As far as I know, the energy of the photons, and the laser, will only change when the wavelength changes, as necessitated by:

$E=\frac{h\ =\ 6.62606876(52)\ \times\ 10^{-34}\ J\ s}{λ}.c$

where E is the energy, h is the Planck's constant, c is the speed of light and λ is the wavelength.

So, when we try to increase the energy of the laser in our process, I don't know it is done by either changing the wavelength or any other way.

Hope this makes things clearer.
Thanks.

4. Apr 7, 2012

### predrummer

Yes, it is right. I just realized the formula is just for one photon. :) When calculating the laser pulse energy, you have actually much more photons. So considering the laser pulse, by changing the repetition rate, you can increase the energy of the laser pulse without changing the wavelength. You can even manipulate by playing with pulse width and power of the laser system you have.
Have a look at the laser pulse calculator from the link to see the real contributions of the parameters to pulse energy:
http://www.calctool.org/CALC/phys/optics/pulsed_source

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