- Materials & Industrial Technology
Power Supply Of A Laser Diode
The laser diode has many applications: for example to play and record MP3 or DVD discs, even to make prints and make fine cuts in materials such as skin and wood among others.
The power supply of a laser diode must meet certain characteristics so as not to damage the diode. For example, I show the technical specifications of the most commercial ones below:
650nm 100mw Red Laser Diode
Output Wavelength: 650nm ± 10nm
Package Type: TO-18
Output power: 100mW CW
To obtain a LASER (Light Amplification by Stimulated Radiation Emission), three basic conditions are needed:
• The active medium in conditions.
• Arousal or Pumping to produce population investment.
• The resonant cavity.
The semiconductor material of the P-N junction provides the active medium.
The excitation or pumping is produced by the current that injects minority carriers of very high level.
The resonant cavity formed by reflecting mirrors form the mirrored walls of the LED
To ensure that neither the voltage nor the current exceeds the technical specifications we must be careful in the circuit that will feed it. Below I show a simple circuit and where we use an LM317 regulator.
It is convenient to have the following precautions when working with laser diodes:
- Do not look directly at the light emitted by a laser diode because it may suffer burns and in any case point it at an opaque object to verify its existence.
- Don´t feed the laser diode directly with the battery because you can burn it.
- Don´t touch the laser diode because we induce static and this can damage it.
- The laser diode must have a heat sink to prevent damage.
- Take into account the technical specifications and try not to exceed them by means of a multimeter and monitor both voltage and current.
Below I show two videos of examples where I used this power supply.