Building a Long Pulsed Laser

[shoddy]

Hi Guys,

Before I begin, I would like to highlight that I am newbie to this field, and have loads to learn.

I want to build a long pulsed (~300μs) 1064nm laser w/ an energy density of approx 14J/cm^2, and up to 10Hz.

I am not sure where to get started, so I am hoping that someone on here who is more able than I am can chime in and guide my intuition in the right direction.

The first challenge is getting a hold of a diode that can output that much power. The best I can find a 3W diode on ebay (link).

This obviously poses other issues since it is C/W and I am looking for a pulsed diode. Would mechanical pulsation be a viable alternative ?

Also, I am not sure whether the 3W will be-able to meet or exceed my 14J/cm^2 requirements.

Please advise.

 

[diachi]

Hi Guys,

Before I begin, I would like to highlight that I am newbie to this field, and have loads to learn.

I want to build a long pulsed (~300μs) 1064nm laser w/ an energy density of approx 14J/cm^2, and up to 10Hz.

I am not sure where to get started, so I am hoping that someone on here who is more able than I am can chime in and guide my intuition in the right direction.

The first challenge is getting a hold of a diode that can output that much power. The best I can find a 3W diode on ebay (link).

This obviously poses other issues since it is C/W and I am looking for a pulsed diode. Would mechanical pulsation be a viable alternative ?

Also, I am not sure whether the 3W will be-able to meet or exceed my 14J/cm^2 requirements.

Please advise.

What beam diameter do you require? 14J/cm^2 is a useless measurement to give without specifying the beam diameter.

Even easier, just give us the pulse energy required, not the energy density.

 

[shoddy]

What beam diameter do you require? 14J/cm^2 is a useless measurement to give without specifying the beam diameter.

Even easier, just give us the pulse energy required, not the energy density.

Thanks for the quick reply.

By beam diameter I presume you mean the spot size ? If so, then about 5mm. Alhtough it would be nice if I could vary it between 5-10mm but that's something I can work on at a later date.

Regards

 

[lasersbee]

What actually will this Laser be used for ??

Jerry

 

[diachi]

Thanks for the quick reply.

By beam diameter I presume you mean the spot size ? If so, then about 5mm. Alhtough it would be nice if I could vary it between 5-10mm but that's something I can work on at a later date.

Regards

You're not going to achieve that energy with that pulse duration from a diode.

14J/cm^2 in a 5mm beam works out to an energy of ~2.75J. 2.75J in a 300us pulse results in an optical power output of just under 9.2kW. You won't find a laser diode that can do that.

Also curious about the application.

 

[shoddy]

Thanks for the replies all.

I'll be using it for a skin condition. I have been getting it done professionally but it's expensive, and I'll still have to do it for at least another year which will break the bank. The alternative is to buy one, but the cheap ones don't have enough power, and the ones that do are in the £10k+ range. So I am exploring the possibility of building one myself, in which case I will not only have a laser for life, but an intimate understanding of the technology behind it.

Another motivation is that I've always had a fascination with lasers, and have owned many pointers over the years. I've always wanted to go deeper into it, and this is the perfect opportunity to do so.

You're not going to achieve that energy with that pulse duration from a diode.

14J/cm^2 in a 5mm beam works out to an energy of ~2.75J. 2.75J in a 300us pulse results in an optical power output of just under 9.2kW. You won't find a laser diode that can do that.

Thanks for your insight - 9.2kW, bloody hell. So what do you suggest ? I was under the impression I could use a convex lenses to adjust the beam diameter. Although I probably wouldn't get anywhere near the energy required to serve it's required purpose.

EDIT: what formula did you use to calculate 2.75J for the given beam diameter ?

 

[paul1598419]

It is a bad idea to treat yourself with a laser you built yourself for, what I am assuming is a skin condition, as the ones used by practitioners are quite expensive because the amount of energy density applied to an area at a specific wavelength is a complex set of parameters you are not likely to duplicate.

 

[Cyparagon]

High voltage, high current, high energy, high intensity... one wrong move, and you will injure or kill yourself. This is NOT a project for a novice.

You mentioned £, so you're in the UK presumably. Why is this procedure of yours not covered by the NHS? I smell "Alternative medicine".

 

[shoddy]

Thanks for the input and concern guys.

I am aware of the dangers.

My plan is to study the physics and engineering aspects of it in detail before I start building any lasers. For now I would like to know the basic make up of what I would need to build such a laser, so as to have a idea of how it'll piece together; the details will be filled in as I study the subject in more depth.

Regards

 

[Alaskan]

That kind of pulse length and power at that wavelength would best be produced using a high voltage flash tube pumped ND:YAG without a Q-switch.

 

[lasersbee]

Thanks for the input and concern guys.

I am aware of the dangers.

My plan is to study the physics and engineering aspects of it in detail before I start building any lasers. For now I would like to know the basic make up of what I would need to build such a laser, so as to have a idea of how it'll piece together; the details will be filled in as I study the subject in more depth.

Regards

This is an accident that is waiting to happen..
Heed the warnings and don't self heal yourself
with a ~10W Laser... You will live longer with
less pain.

Jerry

 

[Encap]

It is a bad idea to treat yourself with a laser you built yourself for, what I am assuming is a skin condition, as the ones used by practitioners are quite expensive because the amount of energy density applied to an area at a specific wavelength is a complex set of parameters you are not likely to duplicate.

Exactly

You're not going to achieve that energy with that pulse duration from a diode.
14J/cm^2 in a 5mm beam works out to an energy of ~2.75J. 2.75J in a 300us pulse results in an optical power output of just under 9.2kW. You won't find a laser diode that can do that.
Also curious about the application.

Exactly--there are no diode lasers that will do that

High voltage, high current, high energy, high intensity... one wrong move, and you will injure or kill yourself. This is NOT a project for a novice.
You mentioned £, so you're in the UK presumably. Why is this procedure of yours not covered by the NHS? I smell "Alternative medicine".

Exactly

This is an accident that is waiting to happen..
Heed the warnings and don't self heal yourself
with a ~10W Laser... You will live longer with
less pain.
Jerry

Exactly

Thanks for the input and concern guys.

I am aware of the dangers.

My plan is to study the physics and engineering aspects of it in detail before I start building any lasers. For now I would like to know the basic make up of what I would need to build such a laser, so as to have a idea of how it'll piece together; the details will be filled in as I study the subject in more depth.

Regards

You are not even aware of the technology much less the dangers --get real :crackup:

Nobody in their right mind is going to participate in the rogue construction of a medical condition treatment laser by someone who has no clue about the technology nor any training concerning the use for medical treatment of any "skin condition" + no Registration nor License to practice medical anything.
Basically you have indicated that you are unfit to create a medical treatment laser and unfit to practice medicine so......

Come back to LPF when you have something more than a daydream/make believe about self treatment with an envisioned home made or other laser device of unknown safety and efficacy

 

[Alaskan]

This is probably a variation of the other help me troll posts from the same guy who keeps asking for medical advice in relation to lasers. Thread closed, perhaps should delete it like the others.