Overpowering my laser makes it dimmer, why?

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In summary, the conversation discusses the purchase of laser diodes on Amazon and the experiment of putting more power through them. The diodes initially produce a bright red dot but then dim over time. The reason behind this dramatic change in resistance and the potential damage to the diodes is questioned. The possibility of a limit circuit built into the circuit board is also mentioned as a way to prevent damage from excessive current. It is noted that laser diodes are very sensitive to overloading and can be easily destroyed.
  • #1
iScience
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I bought some laser diodes on amazon. They're the typical small red 5mW lasers. Just wanted to see if the diode handle more power so i put about 20 - 30mW through it. Nice bright red dot on the wall, but then it dims and dims. The diode didn't get super hot it just got a little hot. But I've never seen such a dramatic change in resistance with so little thermal energy. Would someone mind explaining why?

I know the basics behind a diode, I don't know much about the physics behind lasers though, but since it is called a laser "diode," if i treat it as a diode, which is a semiconductor, wouldn't thermal energy just put more charge carriers in the conduction band?
 
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  • #2
The circuit board may have a limit circuit built in. From here: http://www.teamwavelength.com/info/laserdiodedrivers.php

Limit Circuit: One way to damage a laser diode is to drive too much current through it. Each laser diode datasheet will specify a maximum operating current. Exceeding this current will damage the laser diode. To avoid this, a limit circuit is included in the laser diode power supply. The user determines the maximum setting and the output current is kept from exceeding that level. Some limit circuits cap the current at the max level and keep operating. An Active Current Limit circuit will disable the laser diode driver current.
 
  • #3
Actually, laser diodes are very sensitive to overloading. Even a very short spike in the forward current can destroy them or greatly shorten their lifetime.
 

Related to Overpowering my laser makes it dimmer, why?

1. Why does overpowering my laser make it dimmer?

Overpowering a laser refers to increasing the input power or current beyond the recommended level. This can cause the laser to become dimmer because it leads to a phenomenon known as "thermal lensing." This is when the heat generated by the increased power causes the laser's crystal or lens to deform, resulting in a distorted beam and reduced output power.

2. Can overpowering my laser damage it?

Yes, overpowering a laser can potentially damage it. The excess heat generated by the increased power can cause the laser's components to degrade or even melt, resulting in permanent damage to the laser. In some cases, this can also lead to a safety hazard, as the laser may become unstable and emit dangerous levels of radiation.

3. How can I prevent my laser from becoming dimmer when overpowering it?

The best way to prevent your laser from becoming dimmer when overpowering it is to follow the manufacturer's recommended power levels. These are carefully calculated to ensure optimal performance and safety. If you need a more powerful laser, it is best to invest in a higher-powered laser rather than trying to increase the power of your current one. Additionally, using proper cooling methods and monitoring the laser's temperature can help prevent thermal lensing.

4. Are there any benefits to overpowering a laser?

In some cases, overpowering a laser can provide a temporary boost in output power. However, this is not recommended as it can result in damage to the laser and may not produce the desired results. It is always best to use a laser within its recommended power range for optimal performance and safety.

5. How can I fix a laser that has been damaged by overpowering?

Depending on the extent of the damage, fixing a laser that has been damaged by overpowering can range from simple repairs to needing a complete replacement. It is best to consult with a professional laser technician or the manufacturer for proper repairs. However, prevention is always better than fixing a damaged laser, so it is important to use the laser within its recommended power levels.

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