Sharp GH04955A2G/ The New 495nm diodes

[Singlemode Laser]

Thank you, decent radiation angles for both sides, fairly low like a single mode, are they?

They are single mode indeed.

Singlemode

 

[Alaskan]

I've had one member tell me if you drive SM diodes hard enough, they can become MM, have you seen that yourself?

 

[Singlemode Laser]

I've had one member tell me if you drive SM diodes hard enough, they can become MM, have you seen that yourself?

This is not possible for an undamaged single mode diode.

Singlemode

 

[paul1598419]

I have seen the preliminary data sheet as well. But, much of my knowledge about this diode has come from testing so many at different drive currents and measuring the center wavelength. I have had some in copper modules at 350 mA and the module gets hot in a matter of 20 seconds.

 

[paul1598419]

I have the preliminary results for the first five diodes I received today and will post all results here from now on so I don't have to post to other threads.

So far I have found that these diodes will tend to sift up in wavelength by ~1nm from threshold current to 130 mA with the temperature held constant.

The first five are in order of wavelength:

486.8nm at 55 mA, threshold current
487.4nm at 70 mA
487.2nm at 55 mA and 488.3nm at 130 mA
490.3nm at 120 mA
491.8nm at 100 mA

I may see some among the remaining fifteen that are closer to 495nm, but that remains to be seen. :thanks:

 

[T_Warne]

Is there much visible difference to the naked eye between the 486.8nm and the 491.8nm?

 

[ZRaffleticket]

There is a noticeable difference from 485nm to 488nm. I would say yes.

485nm vs 488nm

 

[paul1598419]

I'm far too busy running these tests to compare wavelengths by sight. I only see them one at a time. They are quite blue to my eyes, though.

 

[Emialias]

so how many of these are actually stable at 495nm and not under?

 

[Singlemode Laser]

so how many of these are actually stable at 495nm and not under?

So far I have found that these diodes will tend to sift up in wavelength by ~1nm from threshold current to 130 mA with the temperature held constant.

The first five are in order of wavelength:

486.8nm at 55 mA, threshold current
487.4nm at 70 mA
487.2nm at 55 mA and 488.3nm at 130 mA
490.3nm at 120 mA
491.8nm at 100 mA

I may see some among the remaining fifteen that are closer to 495nm, but that remains to be seen. :thanks:

Singlemode

 

[paul1598419]

More results for everyone. The next six diodes:

490.7nm at 80 mA
487.6nm at 110 mA
486.9nm at 100 mA
490.0nm at 95 mA
490.2nm at 100 mA
490.8nm at 130 mA.

It is beginning to look like the majority of these will be at or around 490nm to 491nm. There are some lower ones, but not as many as there are these slightly higher ones. I still have nine diodes left to test. Hopefully, this will be good news for many members here who are looking for something around 490nm. :yh:

 

[Sta]

Just bought one. Looks like a great diode.

 

[T_Warne]

well... dang it! I guess now I NEED one of each.

There is a noticeable difference from 485nm to 488nm. I would say yes.

485nm vs 488nm

 

[Alaskan]

I like 490 but 488!! Gimme!

 

[paul1598419]

There are some 488nm ones, but not as many as the slightly higher wavelengths. I was really expecting to see 492nm to 495nm, so no one was more surprised that I when they measured what they have, so far. I will have to get back to the rest after today. I am beat.

 

[paul1598419]

Finally finished measuring the last nine diodes. No great surprises from the first eleven. Here they are,

487.0nm at 75 mA
487.0nm at 95 mA
491.2nm at 100 mA
489.3nm at 120 mA
489.5nm at 150 mA
490.0nm at 100 mA
488.2nm at 80 mA
489.9nm at 90 mA
489.5nm at 110 mA

BTW, I did run one up to 300 mA to see if it would take it. It did, so no worries there.

The temperature was held constant while measuring these diodes so that would not effect the results.