Welcome to Laser Pointer Forums - discuss green laser pointers, blue laser pointers, and all types of lasers



Why are blue lasers much higher output than green lasers ?

Accutronitis

Banned
Joined
Dec 30, 2016
Messages
1,414
Points
0
Why are blue lasers much higher output than green lasers ?

Green seem to have max output of around 1 watt while blue seems to be max output of around 7 watts ? :wtf:
 



diachi

Well-known member
Joined
Feb 22, 2008
Messages
9,793
Points
113
energy is inversely proportional to wavelength. the higher the wavelength, the lower the energy
I see, Thanks......

That's not the reason though. It has nothing to do with it. 1W is 1W is 1W. 1W of 520nm is the same as 1W of 445nm, it's just that the 445nm needs to emit less photons to achieve that 1W output as each photon has more energy.

Differences in available materials as well as demand.

For pointers, DPSS is difficult to get up past 1W in that form factor, just the way DPSS works. You need active temperature control, more optics, lots of pump power etc. Hard to do in a small form factor. I've been around 532nm green lasers that are doing >40W average and a few kWs peak, but that took ~300lbs of cooling equipment, electronics and optical components to achieve. That said, those powers can be achieved much more efficiently and in much smaller form factors with modern technology.

For 520nm diode lasers, the technology is newer, it's had less time to develop. There may also be less demand for more powerful 520nm diodes. For displays you need less green power anyway as it's already a lot brighter than blue, so you may need say 4W of 445nm to match 1W of 520nm. Thus, no large scale demand for direct diode green more than a watt or so.
 
Last edited:

Eracoy

Active member
LPF Site Supporter
Joined
Jul 21, 2014
Messages
172
Points
43
For a single photon, yes, energy is directly proportional to frequency. Though, I'd imagine the total output is much more affected by efficiencies in diode technology.

Edit: Diachi beat me to the explaination and gave a more thorough one.
 
Last edited:

Accutronitis

Banned
Joined
Dec 30, 2016
Messages
1,414
Points
0
That's not the reason though. It has nothing to do with it. 1W is 1W is 1W. 1W of 520nm is the same as 1W of 445nm, it's just that the 445nm needs to emit less photons to achieve that 1W output as each photon has more energy.

Differences in available materials as well as demand.

For pointers, DPSS is difficult to get up past 1W in that form factor, just the way DPSS works. You need active temperature control, more optics, lots of pump power etc. Hard to do in a small form factor. I've been around 532nm green lasers that are doing >40W average and a few kWs peak, but that took ~300lbs of cooling equipment, electronics and optical components to achieve. That said, those powers can be achieved much more efficiently and in much smaller form factors with modern technology.

For 520nm diode lasers, the technology is newer, it's had less time to develop. There may also be less demand for more powerful 520nm diodes. For displays you need less green power anyway as it's already a lot brighter than blue, so you may need say 4W of 445nm to match 1W of 520nm. Thus, no large scale demand for direct diode green more than a watt or so.
Thanks ! That makes perfect sense ! :wave:
 

Rivem

Well-known member
Joined
Feb 16, 2016
Messages
1,242
Points
83
Just to add a bit more on the diode laser side, the power levels mostly have to do with the properties of available semiconductor materials.

Every color of diode laser uses a different type of semiconductor to achieve a bandgap (energy difference) equivalent to its wavelength of light. Some of these semiconductors are just much more efficient than others.

Coming up with new wavelengths and dramatically improving efficiencies requires discovering new semiconductors or using novel techniques to change the quantum properties of lasing cavities.
 

HydroSean

New member
Joined
Mar 25, 2016
Messages
529
Points
0
That's not the reason though. It has nothing to do with it. 1W is 1W is 1W. 1W of 520nm is the same as 1W of 445nm, it's just that the 445nm needs to emit less photons to achieve that 1W output as each photon has more energy.

Differences in available materials as well as demand.

For pointers, DPSS is difficult to get up past 1W in that form factor, just the way DPSS works. You need active temperature control, more optics, lots of pump power etc. Hard to do in a small form factor. I've been around 532nm green lasers that are doing >40W average and a few kWs peak, but that took ~300lbs of cooling equipment, electronics and optical components to achieve. That said, those powers can be achieved much more efficiently and in much smaller form factors with modern technology.

For 520nm diode lasers, the technology is newer, it's had less time to develop. There may also be less demand for more powerful 520nm diodes. For displays you need less green power anyway as it's already a lot brighter than blue, so you may need say 4W of 445nm to match 1W of 520nm. Thus, no large scale demand for direct diode green more than a watt or so.
Yeah I forgot to include an explanation about the DPSS green lasers and that is totally true. But for just single diode InGaN lasers the reason is still due to Debroglie's law since these InGaN blue and green diodes use the same semiconductor dopants.
 
Last edited:

Encap

Well-known member
Joined
May 14, 2011
Messages
5,515
Points
113
There are many different laser technologies. The two that are used in pointers are DPSS and Direct diode.
You can read up on the differences between DPSS and Diode laser technology here: https://en.wikipedia.org/wiki/Laser_pointer and here: https://en.wikipedia.org/wiki/Diode-pumped_solid-state_laser and here: https://en.wikipedia.org/wiki/Diode_laser

If you are meaning by green 532nm green, 532nm green is only created by a DPSS process which is a much more expensive and complicated technology, requiring hand work and fine tuning and has better quality beam than low cost diode lasers. A 700mW 532nm from either laserbtb or jetlasers cost aprox $700 -- $1 per mW. So demand is small due to the expense. A DPSS laser is not something a hobbyist can build generally . 532nm green is so many times brighter to the eye than blue there is little if any call for anything more powerful than 1W as others have said. A 1w 532nm is much brighter than a 7W 445 see: http://lsrtools.1apps.com/relativebrightness/?nm1=445&mw1=7000&nm2=532&mw2=1000&useRaleigh=off

Low cost mass produced direct diode lasers are much more affordable beause of the many products they are used in where the quality of the laser output does not really matter much. Since the development of direct diode 520nm green it has become popular due to low cost and availability as well. Hobbyist can easily make a pointer containing a direct diode laser---so they are the hobby for the most part.
 
Last edited:




Top