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How to generate pulsed laser in Bioheat Eq.

Posted 03.03.2013, 20:28 GMT-5 RF & Microwave Engineering, Heat Transfer & Phase Change, Modeling Tools & Definitions, Parameters, Variables, & Functions Version 4.4 2 Replies

Taehoon Kim
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For Bioheat equation, there is one parameter which I can input corresponding to laser source, Q_ext (spatial heat source)

In this part, I typed the equation of laser radiation below,

I0*a*exp(a*z-r^2/(2*sigma^2))

and this is all what I could do.

The laser of course radiated as CW(continuous wave) mode.

I need to use the laser source as a pulsed mode.

What should I do?

2 Replies Last Post 14.01.2015, 13:17 GMT-5
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago 04.03.2013, 01:13 GMT-5
Hi

first of all you have the gp1() (Gaussian pulse, check the help for the normalisation, its slightly hidden ;) under "model - Definitions - Functions". So if you have a pulsed laser and you are interested in the pulse response, you must do a time series over the pulse length (you can use another gp2() for the temporal shape. But if you have a pulse train, you can use the average energy to, all depends where you interest are (or a single pulse response to get the energy balance and an average value thereafter ...

--
Good luck
Ivar
Hi first of all you have the gp1() (Gaussian pulse, check the help for the normalisation, its slightly hidden ;) under "model - Definitions - Functions". So if you have a pulsed laser and you are interested in the pulse response, you must do a time series over the pulse length (you can use another gp2() for the temporal shape. But if you have a pulse train, you can use the average energy to, all depends where you interest are (or a single pulse response to get the energy balance and an average value thereafter ... -- Good luck Ivar
Affar Karimullah
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Posted: 9 years ago 14.01.2015, 13:17 GMT-5
I am trying to generate a model where I can look at the heat dissipation in a plasmonic structure when irradiated by a ns pulsed laser. I have managed to make a model where I can solve the emf simulation and then a time dependant heat transfer simulation, however I think this is modeling a CW laser source. I would like to be able to tell comsol to have a laser source for 30ns and then stop. I was wondering if another study step with just a time dependent step for the heat transfer would work, but I am unsure how to get the temperature data from the first study step to the second. I have attached the model file. Any advice?
I am trying to generate a model where I can look at the heat dissipation in a plasmonic structure when irradiated by a ns pulsed laser. I have managed to make a model where I can solve the emf simulation and then a time dependant heat transfer simulation, however I think this is modeling a CW laser source. I would like to be able to tell comsol to have a laser source for 30ns and then stop. I was wondering if another study step with just a time dependent step for the heat transfer would work, but I am unsure how to get the temperature data from the first study step to the second. I have attached the model file. Any advice?

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