Laser Diode Pulsing Question

[CHPCHP]

Many high-power laser diodes’ Power vs Current curves show the thermal rollover. I’m guessing some of this is due to the dwell time required for the detector’s thermopile to thermally stabilize to provide an accurate reading.

Have any of you tried pulsing the laser diode with a short pulse to get even higher peak power?

I’m guessing the pulse width is related to the transient thermal impedance of the system.

Here are my initial concerns with this high-power pulsing idea:

1) The high peak current will create thermal/mechanical stresses in the laser chip. This may be mitigated by using a slow current rise time.

2) The higher peak output power may damage the dielectric mirrors.

3) The higher current may stress the bond wire connection to the laser chip. This may be a long-term effect.

4) The higher peak output power may crack the laser diode window.

Any other concerns?

I did super pulsing on a CO2 laser rifle 15-20 years ago, where I’d double the initial current to the tube and quickly drop down to rated current. This extra optical oomph could help initiating ablation of the surface to allow the normal laser power to penetrate.

 

[RedCowboy]

Have you done a search, here's just a couple results.

L

Thread 'Pulsed laser diode drivers?'

Jul 7, 2008

Is anyone making pulsed drivers for laser diodes or have a good design for one?   Spec sheets often rate a 90mW CW 650nm diode much higher in pulsed mode, eg typically something like 200-250mW.  Now, unless this description is misleading, 250mW pulsed (at however many Mhz) means 250mW true power, i.e. 0.25Watts/second on average at high rep rate.  As far as the eye or any target is concerned this would be indistinguishable from 250mW 'true' CW.  

I hope the 90mW V 250mW rating isn't just a CW verses peak 'nano-second' type power rating in other words a matter of manipulating the duty...

• LikeitBright
• Replies: 11
• Forum: General

pulsed blue laser

hello, I want to get nanosecond(0.5ns--100ns) pulse from a blue laser diode(405nm/445nm), high power around watt level is preferred. if someone work on pulsed laser diode, can you give some advices on both laser diode module and laser driver. I have found Nichia NDB7875, however the...

photonlexicon.com

 

[CHPCHP]

I appreciate the search, but I didn’t see anything close to what I was asking. The laser diode technology in 2008 was much different than now, and I don’t need help building a power supply.

I was focusing on our new high power laser diodes (445nm at ~6 watts rated from the manufacturer) which do not have a pulsed ratings on their spec sheet. The physics of the new laser dies and the intended application is different than the old style laser diodes.

 

[Encap]

The obvious answer is purchase a few diodes and experiment with them to determine unconventional data you want to determine for whatever reasons.
The data developed for diodes that were not meant for or designed for the use you want to play with is not available or has not been established/developed. There is no significant diode marketing reason for same so if the makers have some date on pulsed use they do not bother to publish it. No $ or other reason to. They are sold by the hundreds of thousands for the purpose/use they were designed and intended for.

Get a couple of these which seem to be robust and take more abuse than other when pushed beyond their intended 6W output rating. https://laserpointerforums.com/threads/jlasers-gh04c06v9g-true-10w-diode.111815/#post-1633139

 

[CHPCHP]

he obvious answer is purchase a few diodes and experiment with them to determine unconventional data you want to determine for whatever reasons.
The data developed for diodes that were not meant for or designed for the use you want to play with is not available or has not been established/developed. There is no significant diode marketing reason for same so if the makers have some date on pulsed use they do not bother to publish it. No $ reason to they are sold by the hundreds of thousands for the purpose/use they were intended for.

Get a couple of these which seem to be robust and take more abuse than other when pushed beyond their intended 6W output rating.

Which is exactly why I was asking if anyone here had experience pulsing the new high-power laser diodes as a head start.

BTW, I'm not a new member here. I've been here since 2007 or so. My previous username CHP was hacked and I had to re-register.

 

[RedCowboy]

I think Laserer pulsed a 445nm, however that was a while back, the evolved 445-465nm multi mode diodes are tougher, pushed past foldback for a moment they recover rather than going led, could possibly be pulsed to higher peaks with the right duty cycle and temp control.

 

[CHPCHP]

I think Laserer pulsed a 445nm, however that was a while back, the evolved 445-465nm multi mode diodes are tougher, pushed past foldback for a moment they recover rather than going led, could possibly be pulsed to higher peaks with the right duty cycle and temp control.

Thank you.

 

[Encap]

Unfortunately you are not going to find much help on LPF as laser pointer people have always avoided/rejected pulsed laser pointers unless forced to accept a few pulsed pointers like CNI made and marketed long ago. Continuous wave pointers being the preferred choice and what all of the hundreds of makers make and offer.

If you are set on exploring and making a pulsed laser out of diodes designed,made, and sold to be used as continuous wave lasers he only real answer is to do the experimenting yourself using as robust a laser diode as you can obtain that tolerates being overdriven and abused a least for a period of time like the one I mention here. A 6W 445nm diode that will tolerate being pushed to 10W with proper heat sink and temperature control --would be a good choice to experiment with. See: https://laserpointerforums.com/threads/jlasers-gh04c06v9g-true-10w-diode.111815/#post-1633139

 

[atomd]

You can subnanosecond pulse laser diodes with up to few times higher optical power than rated max power, up to COD.

 

[CHPCHP]

Unfortunately you are not going to find much help on LPF as laser pointer people have always avoided/rejected pulsed laser pointers unless forced to accept a few pulsed pointers like CNI made and marketed long ago. Continuous wave pointers being the preferred choice and what all of the hundreds of makers make and offer.

If you are set on exploring and making a pulsed laser out of diodes designed,made, and sold to be used as continuous wave lasers he only real answer is to do the experimenting yourself using as robust a laser diode as you can obtain that tolerates being overdriven and abused a least for a period of time like the one I mention here. A 6W 445nm diode that will tolerate being pushed to 10W with proper heat sink and temperature control --would be a good choice to experiment with. See:

I agree with you.

 

[CHPCHP]

You can subnanosecond pulse laser diodes with up to few times higher optical power than rated max power, up to COD.

I can see that for some laser diodes. However, many people are running the higher output laser diodes over 1.7 times max rating in cw.