What is a Laser diode, how Laser diode works, and how to connect a Laser diode with Arduino are some questions that may arise in your mind while working with a Laser diode and Arduino.
Hello guy! Welcome back to my blog today we are going to see
about Laser diode so let’s begin.
What is a Laser diode??
LASER stands for “Light Amplification by Stimulated Emission of Radiation”. The laser diode is a semiconductor device just like the P-N junction diode which emits laser radiation when connected to the supply in forwarding bias. The only difference between a laser diode and a p-n junction diode is that the laser diode has an intrinsic layer of GaAs sandwiched between p-n regions. The edge of the intrinsic layer has a mirror-like finish. Light emitted by p-n junction LED, bulbs, and the sunlight is non-coherent in nature. They produce multiple waveforms that are out of phase and frequency whereas the light emitted by Lasers diodes is coherent in nature means lights have the same phase and frequency. The process of coherent light emission from a diode is called as spontaneous emission process. Also, laser lights are monochromatic in nature. Laser diode produces higher energy of light radiation. Light emitted by the Laser diode is Collimated means they travel in one and the same direction. We have laser applications in security systems, barcode scanners, metal cutting, medical treatment, printers, etc. Laser diodes produce a narrow beam of light in a single path and have a high brightness level. The laser diode is low cost, easy to use, and gives a fast response.
How laser diode works??
The laser diode is made of three layers the first layer consists of p-type material, the third layer consists of n-type material and the intrinsic layer is sandwiched between p-type and n-type material is preferred as a middle layer. The metal plate is referred to as the input terminal for the P & N type region. The layers of semiconductors used in the construction of Laser diode are made up of GaAs doped with materials like silicon selenium or aluminum. The surface of the intrinsic layer has reflective polishing. P-type material consists of holes as the majority charge carrier whereas n-type material consists of electrons as the majority charge carrier.
When laser diode is connected in forwarding bias means
(positive side of battery connected to p-type material and negative side of
battery connected to n-type material) than similar charge carrier gets repel from the battery and accumulate in intrinsic layer. The intrinsic layer is an undoped region
where the recombination of electrons and holes takes place. The process of creation of
laser light depends upon three processes Absorption, Spontaneous Emission, and Stimulated Emission.
When an external voltage is applied to the laser diode then electrons present in the valence band absorb some energy and jump into the conduction band means electrons jump from a lower energy state to a higher energy state. The electrons now at a higher energy state wait for some amount of time before falling down is called recombination time.
In the Spontaneous Emission state electron which was present in a higher energy state falls towards a lower energy state. But while falling from a higher energy state it emits photons. The energy of the emitted photon is given by the difference between the two energy levels.
As discussed earlier intrinsic layer has a mirror-type finishing
surface for reflection. When electrons fall from a higher energy level to a lower energy level it emits some photons but due to reflecting mirror polishing at the surface intrinsic layer, photon reflects back and forth to generate multiple
photons. Due to higher power lights generated it escapes the layer and passes
through the focus lens to give a narrow beam of light that can travel a larger
distance.
Here we have seen the P-I character list of laser diode first
electron jumps to a higher level so the initial value in the y-axis is recombination
time. Later electrons fall to a lower energy level leaving a photon behind which
is known Spontaneous Emission region. After crossing a certain threshold value
more photons are generated so this region is called as Stimulated Emission.
Difference between Laser diode and LED
| Sr.no | Parameter | LED | Laser |
|---|---|---|---|
| 1) | Full-form | LED stands for light-emitting diode | LASER stands for light amplification by stimulated emission of radiation |
| 2) | Response | Fast | Faster than LED |
| 3) | Energy | Low | High |
| 4) | bandwidth | Moderate | High |
| 5) | Nature of light | non-coherent & polychromatic | Coherent & monochromatic |
| 6) | Cost | Low cost | Slightly more expensive than LED |
| 7) | safety | Eye-safe device | Safety must be considered |
| 8) | Working principle | Spontaneous emission. | stimulated emission |
| 9) | Application | Only Multimode | Both Single mode and multimode |
Application of laser diode
- In optical fiber
- Barcode reader
- Metal cutting
- Security systems
- Medical surgeries
- CD/DVD players
- Military defense equipment
- Laser printers
- Toys
Parts Required
- KY-008 Laser Module 650NM 5V
- Arduino
- Jumper wires
- Breadboard
Circuit Diagram
Connect the ground pin of a ky-008 laser sensor to the ground pin of Arduino, the VCC pin to 5v, and the Signal pin to 8.
Code -
First, initialize pins of Laser pins. We have declared a variable name Laser_pin. In the void setup, we configure pins as INPUT or OUTPUT. We want to emit laser light from the sensor, so we will declare it as OUTPUT. We also configure the baud rate to 115200.
In the void loop, we continuously read just turn ON the Laser light and turn OFF the laser light through the digitalWrite function. to turn ON the laser pin we will pass HIGH and for turning OFF the laser light we will pass LOW as an argument inside digitalWrite() function.
OUTPUT -
Conclusion -
Today we learn about what is a laser diode, how to use a laser diode with Arduino, the working principle of laser diode, the difference between the laser diode and LED, and the Application of laser diode. laser diodes are inexpensive small in size and easy to use devices. the light emitted from laser light travels more distance than LED.
"I hope you find this IoT blog very helpful to you. In the upcoming lesson, we will see more about IoT sensors till then bye. See you all in my next blog."
