Introduction of Ruby LASER
A ruby laser is a solid-state laser that uses a synthetic ruby crystal as its gain medium. It was the first type of laser invented and first time operated by Theodore H. “Ted” Maiman at Hughes Research Laboratories on 1960-05-16. The ruby mineral (corundum) is aluminum oxide with a small amount (about 0.05%) of chromium. Which gives it its characteristic pink and/ or red color by absorbing green and blue light.
The ruby laser is used as a pulsed laser, producing red light at 694.3 nm. After receiving a pumping flash from the flash tube. The laser light emerges for as long as the excited atoms persist in the ruby rod, which is typically about a millisecond. To understand any LASER three different processes of LASER should be clear i.e., absorption, spontaneous emission, and stimulated emission.
Ruby Laser’s Historical Importance
A pulsed ruby laser was used for the famous laser ranging experiment which was conducted with a corner reflector placed on the Moon by the Apollo astronauts. This determined the distance to the Moon with an accuracy of about 15 cm. a three-level solid-state laser.
Construction and Working of Ruby LASER
The active laser medium (laser gain/amplification medium) is a synthetic ruby rod. Ruby is an aluminum oxide crystal in which some of the aluminum atoms have been replaced with chromium atoms (0.05% by weight). Chromium gives ruby its characteristic red color and is responsible for the lasing behavior of the crystal. Chromium atoms absorb green and blue light and emit red and pink light. For a ruby laser, a crystal of ruby is formed into a cylinder.
The rod’s ends had to be polished with great precision, such that the ends of the rod were flat to within a quarter of a wavelength of the output light, and parallel to each other within a few seconds of arc. The finely polished ends of the rod were silvered: one end completely, the other only partially. The rod with its reflective ends then acts as a Fabry-Pérot etalon.
Working
A xenon lamp is rolled over the ruby rod and is used for pumping ions to an excited state. Ruby laser is based on three energy levels. The upper energy level E3 I is short-lived, E1 is the ground state, and E2 is the metastable state with a lifetime of 0.003 sec. When a flash of light falls on the ruby rod, radiations of wavelength 5500 are absorbed by Cr3+ which are pumped to E3. The ions after giving a part of their energy to the crystal lattice decay to the E2 state undergoing radiation-less transition.
In a metastable state, the concentration of ions increases while that of E1 decreases. Hence, population inversion is achieved. A spontaneous emission photon by the Cr3+ ion at the E2 level initiates the stimulated emission by other Cr3+ ions in the metastable state
RUBY LASER CONSTRUCTION AND WORKING VIDEO TUTORIAL
Applications of Ruby LASER
Ruby lasers have declined in use with the discovery of better lasing media. They are still used in several applications where short pulses of red light are required. Holographers around the world produce holographic portraits with ruby lasers, in sizes up to a meter squared. Many non-destructive testing labs use ruby lasers to create holograms of large objects such as aircraft tires to look for weaknesses in the lining. Ruby lasers were used extensively in tattoo and hair removal.
FAQs Ruby LASER
First, understand these three main components to explain any laser;
1. Lasing medium: it is the ruby rod in the form of ruby crystal;
2. Pumping process: The optical pumping in the form of a helical xenon flash lamp,
3. Resonator cavity: a container where all set-up is fixed. It is made of a full reflector and partially reflecting glass plates, which are parallel with high accuracy.
1Q. What is the construction and working of Ruby Laser Light?
1Ans. This is explained in the above sections.
2Q. What is the working substance in ruby laser?
2Ans. Ruby crystal, i.e., a crystal of Aluminium oxide (Al2O3) in which chromium oxide is mixed as an impurity so that some of the Al3+ ions are replaced by Cr3+ ions. Chromium ions with a concentration of about 0.05% by weight.
3Q. What is the construction of the laser action?
3Ans. For the laser action we require 3 components i.) lasing medium i.e., ruby crystal ii). Optical pumping process; here we have used the xenon flash tube iii). and resonator cavity that is formed by the two parallel glass plates. These are the main components after explanation of these make the figure that shows all of these.
4Q. What are the parts of a ruby laser?
4Ans. 3 main components are mentioned above.
5Q. What is the construction of a ruby laser?
5Ans. Same as 3Q.
6Q. What is the working principle of ruby?
6Ans. Any LASER works well if it follows the Population inversion process.
This is achieved by the optical pumping process. Do you know how? Actuall xenon flash lamp emits two radiations of green and blue color; 4500A0 and 5500A0 respectively. This radiation is absorbed by the Ruby crystal. The chromium atoms in the ruby rod absorb it and go into the excited state corresponding to the E21 and E22. Now after excitation what will happen, these excited atoms de-excite and reach the metastable state. Now the transition from the metastable state to the ground state is responsible for the LASER light.
7Q. What is the application of ruby laser?
7Ans. There are many applications of the Ruby LASER. Mainly used for holography, aircraft tires to look for weaknesses in the lining. Also used extensively in tattoo and hair removal.
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