How Lasers Work | Laser Micromachining | Lasers in Industry | Picosecond Lasers | Ultrafast Lasers

Lasers are everywhere and used in a wide variety of applications. They are found in barcode scanners, DVD players used in medicine, produce dazzling laser light shows and of course, instrumental in micro manufacturing. The acronym LASER stands for Light Amplification by Stimulated Emission of Radiation. The term was coined by Gordon Gould when he was a student of Dr. Charles Townes at the Columbia University in 1957. Lasers exhibit some unique characteristics. They are monochromatic which is to say they output a single wavelength or pure color with an extremely narrow linewidth. Depending on the laser type, they can have wavelengths from the ultraviolet through the visible or even in the infrared portion the electromagnetic spectrum Wavelength selection is important depending on the material being laser processed as an example UV lasers are usually best for drilling and cutting plastics. Lasers are also highly directional would have been can be as little as one millimeter in diameter and spreads very little over a large distance. In fact, lasers have been bounced off the moon to accurately measure the distance between the moon and the Earth They're also coherent, where all the waves are exactly in phase with one another. The common components of all lasers consist of first an active medium which can be a gas such as in a carbon dioxide laser or a Krypton Fluoride for instance in an excimer laser which is used to generate high power UV pulses. A solid-state laser on the other hand has a crystal made of Ruby neodymium-doped yttrium aluminium garnet or YAG as we call it, or Neodymium-doped yttrium lithium fluoride. Just to name a few. The gain medium can even be a liquid although dye lasers are not using micro manufacturing there are several reasons for that. The pumping source or energy input can be electrical such as a HV discharge in excimer lasers or optical using laser diodes for instance to pump Yag or fiber lasers. And lastly, all lasers need an optical feedback which consists of a mirror or high reflector any a partially reflective mirror and we'll talk much more about that later Finally, a population inversion is critical to sustaining laser operation were a large number of atoms are in an excited state looking at the energy level diagram an electron is pumped to a highly excited state and transitions to a metastable region. The electron will seek its natural or ground state however, it must release energy and it does so in the form of a photon. Now, we have a lot of atoms releasing photons in all directions this is called spontaneous emission. This is similar to a blacklight which is the UV pump source and a fluorescence dye The dye absorbs the UV wavelength and emits a visible color in all directions. In lasers, stimulated emission is achieved by the optical cavity. Photons bounce back and forth between the mirrors and as a photon passes an atom in an excited state it too emits a photon creating a cascading or domino effect. The output coupler, being partially reflective, permits the laser beam to exit the cavity. Now, the chart shows the laser types commonly used in manufacturing. Wavelengths can be anywhere from 193 nanometers in the UV to 10.6 microns in the infrared. Average power is typically in the range a few Watts to a few hundred Watts and laser pulse durations can range anywhere from microseconds all the way down to a few femtoseconds. So thank you for viewing and stay tuned for future installments on laser applications in micro-manufacturing. if you have any questions, or if you want to suggest a future topic on lasers in micromanufacturing Please contact me, Thank you.

Channel: PhotoMachining.com

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Keywords: dpss laser, excimer, femtosecond laser, industrial laser, laser contract manufacturing, laser job shop, laser jobshop, laser machining, laser micro fabrication, laser micro machining, laser micro manufacturing, laser microfabrication, laser micromachining, laser micromanufacturing, laser systems, picosecond laser, ultrafast laser, ultrashort laser, uv laser

Id: cJgViCkzg8o

Length: 4min 48sec (288 seconds)

Published: Thu Mar 26 2015