Part-1 Laser & its properties in hindi 👉https://youtu.be/7X1swOBFzJg Part-2 Transition in laser full concept in hindi 👉https://youtu.be/3WuvwXlbpVQ Part-3 Population inversion in laser in hindi 👉https://youtu.be/TYCYE1vufgA Part-4 Principle and working of laser in hindi 👉https://youtu.be/gbY5Z049UrY Part-5 Einstein coefficient and constant with derivation in hindi 👉https://youtu.be/xFZY3n8Ygm4 Part-6 Ruby laser full explanation in hindi 👉https://youtu.be/1hQXKIOF6kE Part-7 helium neon laset full explanation in hindi 👉https://youtu.be/nNUmUoVRbTU In these module : What is Einstein theory of laser, Relation between Einstein coefficient, Rate of absorption, Rate of spontaneous emissions, Rate of stimulated emissions, Einstein constant of coefficient. Planks law of energy. All lectures available in hindi/urdu SUBSCRIBE US FOR MORE UPDATE 😊 #RGPV #RGPVCBCS #ITI #IIT #ENGINEERINGPHYSICS #LASERINHINDI #BTECH #MTECH

"HE-NE LASER CONSTRUCTION AND WORKING" Helium-Neon laser definition: Helium-Neon laser is a type of gas laser in which a mixture of helium and neon gas is used as a gain medium. Helium-Neon laser is also known as He-Ne laser. What is a gas laser? : A gas laser is a type of laser in which a mixture of gas is used as the active medium or laser medium. Gas lasers are the most widely used lasers. Gas lasers range from the low power helium-neon lasers to the very high power carbon dioxide lasers. The helium-neon lasers are most commonly used in college laboratories whereas the carbon dioxide lasers are used in industrial applications. The main advantage of gas lasers (eg: He-Ne lasers) over solid state lasers is that they are less prone to damage by overheating so they can be run continuously. What is helium-neon laser?: At room temperature, a ruby laser will only emit short bursts of laser light, each laser pulse occurring after a flash of the pumping light. It would be better to have a laser that emits light continuously. Such a laser is called a continuous wave (CW) laser. The helium-neon laser was the first continuous wave (CW) laser ever constructed. It was built in 1961 by Ali Javan, Bennett, and Herriott at Bell Telephone Laboratories. Helium-neon lasers are the most widely used gas lasers. These lasers have many industrial and scientific uses and are often used in laboratory demonstrations of optics. In He-Ne lasers, the optical pumping method is not used instead an electrical pumping method is used. The excitation of electrons in the He-Ne gas active medium is achieved by passing an electric current through the gas. The helium-neon laser operates at a wavelength of 632.8 nanometers (nm), in the red portion of the visible spectrum. Helium-neon laser construction: The helium-neon laser consists of three essential components: 1.Pump source (high voltage power supply) 2.Gain medium (laser glass tube or discharge glass tube) 3.Resonating cavityhe helium-neon laser consists of three essential components: 1.Pump source (high voltage power supply) In order to produce the laser beam, it is essential to achieve population inversion. Population inversion is the process of achieving more electrons in the higher energy state as compared to the lower energy state. In general, the lower energy state has more electrons than the higher energy state. However, after achieving population inversion, more electrons will remain in the higher energy state than the lower energy state. In order to achieve population inversion, we need to supply energy to the gain medium or active medium. Different types of energy sources are used to supply energy to the gain medium. In ruby lasers and Nd:YAG lasers, the light energy sources such as flashtubes or laser diodes are used as the pump source. However, in helium-neon lasers, light energy is not used as the pump source. In helium-neon lasers, a high voltage DC power supply is used as the pump source. A high voltage DC supplies electric current through the gas mixture of helium and neon. Gain medium (discharge glass tube or glass envelope): The gain medium of a helium-neon laser is made up of the mixture of helium and neon gas contained in a glass tube at low pressure. The partial pressure of helium is 1 mbar whereas that of neon is 0.1 mbar. The gas mixture is mostly comprised of helium gas. Therefore, in order to achieve population inversion, we need to excite primarily the lower energy state electrons of the helium atoms. In He-Ne laser, neon atoms are the active centers and have energy levels suitable for laser transitions while helium atoms help in exciting neon atoms. Electrodes (anode and cathode) are provided in the glass tube to send the electric current through the gas mixture. These electrodes are connected to a DC power supply. Resonating cavity: The glass tube (containing a mixture of helium and neon gas) is placed between two parallel mirrors. These two mirrors are silvered or optically coated. Each mirror is silvered differently. The left side mirror is partially silvered and is known as output coupler whereas the right side mirror is fully silvered and is known as the high reflector or fully reflecting mirror. The fully silvered mirror will completely reflect the light whereas the partially silvered mirror will reflect most part of the light but allows some part of the light to produce the laser beam. Working of helium-neon laser: In order to achieve population inversion, we need to supply energy to the gain medium. In helium-neon lasers, we use high voltage DC as the pump source. A high voltage DC produces energetic electrons that travel through the gas mixture. The gas mixture in helium-neon laser is mostly comprised of helium atoms. Therefore, helium atoms observe most of the energy ................. READ MORE AT : http://www.physics-and-radio-electronics.com/physics/laser/heliumneonlaser

CHARACTERSTICS OF LASER LIGGHT : What is LASER? Full form of LASER? It's Characteristics like: Directionality, Monochromatic-city, Coherence, and Intensity. There is a comparison of how LASER light is better than an ordinary light. How LASER light is useful in many of the applications in day-to-day life. Introduction: Forum Articles Ask Experts Exams Education Study Abroad More Search ResourcesEducation Introduction to LASER and Characteristics of LASER Posted Date: 14 Apr 2012 |Updated: 14-Apr-2012 |Category: Education |Author: Deepak Shakyavanshi |Member Level: Silver |Points: 20 | What is LASER? Full form of LASER? It's Characteristics like: Directionality, Monochromatic-city, Coherence, and Intensity. There is a comparison of how LASER light is better than an ordinary light. How LASER light is useful in many of the applications in day-to-day life. Introduction: The term LASER stands for Light Amplification by Stimulated Emission of Radiation. The discovery of laser is one of the important discoveries of the last century. The first successful Laser operation was demonstrated by T.Maiman in 1990 using a ruby crystal in USA. In the following year, the first gas laser was fabricated by Ali Javan and co-workers. Since then, different types of lasers using solids, liquids and gasses have been developed. The immense use of laser, from toys to warfare and from welding to surgery have made laser very popular. Characteristics of Laser Light: Like Ordinary light Laser light is electromagnetic in nature. However, there are few characteristics not possessed by the normal light. Some of these characteristic of laser are motioned below: 1.Directionality: The Laser beam is highly directional having no laser divergence(except the diffraction effect). The output beam of Laser has a well defined wavefront and therefore it is highly directional. Due to it's high directionality, a Laser beam can be focused to a point by passing it to a suitable convex lens. If a Laser beam of wavelength 6000 A and beam radius 2 mm is passed through a convex lens of focal length 5 cm, then the area of the spot at the focal plane is extremely small. For a typical Laser beam, the beam divergence is less than 0.01 milliradian, i.e., for a meter of propagation, the spread is less than 0.01 mm. the normal light spreads to about one kilometer for every kilometer of it's propagation. Just imagine how much a normal beam of light would diverge when it reaches moon at a distance of 3,80,000 km while a Laser beam spreads to just a few kilometers on reaching the moon. 2.Monochromatic-city: The Laser light is nearly monochromatic. In reality, no light is perfectly monochromatic, i.e., it is not characterized by a single wavelength or frequency but instead; it is characterized by spread in frequency about the central frequency. 3.Coherence: Laser Radiation is characterized by high degree of coherence, both spatial and temporal. In other words, a constant phase relationship exists in the radiation field of Laser light source at different locations and times. It is possible to observe interference effects from two independent Laser beams. In fact, coherence is main feature which distinguishes Laser radiation from ordinary light and other characteristic are related to high degree of coherence. Ordinary light consists of large number of separate waves without any phase relationship, cancelling and reinforcing each other randomly. The wavefront so produced changes from one point to another and from one instant to instant. Thus there is neither spatial nor temporal coherence in ordinary light. 4.Intensity: Laser Radiation is characterized by high degree of coherence, both spatial and temporal. In other words, a constant phase relationship exists in the radiation field of Laser light source at different locations and times. It is possible to observe interference effects from two independent Laser beams. In fact, coherence is main feature which distinguishes Laser radiation from ordinary light and other characteristic are related to high degree of coherence. Ordinary light consists of large number of separate waves without any phase relationship, cancelling and reinforcing each other randomly. The wavefront so produced changes from one point to another and from one instant to instant. Thus there is neither spatial nor temporal coherence in ordinary light. 4.Intensity: The Laser beam is highly intense compared to ordinary light. Since, the Laser power is concentrated in a beam of very small diameter (few mm); even a small Lase can deliver high intensity at the focal plane of the lens. Note that even a small power of 1 watt can give an intensity of 1000000000 W/m(square), which is extremely large. KNOW MORE AT : http://www.indiastudychannel.com/resources/150894-Introduction-LASER-characteristics.aspx

Einstein Coefficients of laser: Emission lines and absorption lines compared to a continuous spectrum. Einstein coefficients are mathematical quantities which are a measure of the probability of absorption or emission of light by an atom or molecule.[1] The Einstein A coefficient is related to the rate of spontaneous emission of light and the Einstein B coefficients are related to the absorption and stimulated emission of light. Contents [hide] 1 Spectral lines 2 Emission and absorption coefficients 2.1 Equilibrium conditions 3 Einstein coefficients 3.1 Various formulations 3.2 Spontaneous emission 3.3 Stimulated emission 3.4 Photon absorption 4 Detailed balancing 5 Oscillator strengths 6 See also 7 References 7.1 Cited bibliography 8 Other reading 9 External links Spectral lines[edit] In physics, one thinks of a spectral line from two viewpoints. An emission line is formed when an atom or molecule makes a transition from a particular discrete energy level E2 of an atom, to a lower energy level E1, emitting a photon of a particular energy and wavelength. A spectrum of many such photons will show an emission spike at the wavelength associated with these photons. An absorption line is formed when an atom or molecule makes a transition from a lower, E1, to a higher discrete energy state, E2, with a photon being absorbed in the process. These absorbed photons generally come from background continuum radiation (the full spectrum of electromagnetic radiation) and a spectrum will show a drop in the continuum radiation at the wavelength associated with the absorbed photons. The two states must be bound states in which the electron is bound to the atom or molecule, so the transition is sometimes referred to as a "bound–bound" transition, as opposed to a transition in which the electron is ejected out of the atom completely ("bound–free" transition) into a continuum state, leaving an ionized atom, and generating continuum radiation. A photon with an energy equal to the difference E2 - E1 between the energy levels is released or absorbed in the process. The frequency ν at which the spectral line occurs is related to the photon energy by Bohr's frequency condition E2 - E1 = hν where h denotes Planck's constant.[2][3][4][5][6][7] Emission and absorption coefficients[edit] An atomic spectral line refers to emission and absorption events in a gas in which {\displaystyle n_{2}} n_{2} is the density of atoms in the upper energy state for the line, and {\displaystyle n_{1}} n_{1} is the density of atoms in the lower energy state for the line. The emission of atomic line radiation at frequency ν may be described by an emission coefficient {\displaystyle \epsilon } \epsilon with units of energy/time/volume/solid angle. ε dt dV dΩ is then the energy emitted by a volume element {\displaystyle dV} dV in time {\displaystyle dt} dt into solid angle {\displaystyle d\Omega } d\Omega . For atomic line radiation: {\displaystyle \epsilon ={\frac {h\nu }{4\pi }}n_{2}A_{21}\,} \epsilon ={\frac {h\nu }{4\pi }}n_{2}A_{21}\, where {\displaystyle A_{21}} A_{21} is the Einstein coefficient for spontaneous emission, which is fixed by the intrinsic properties of the relevant atom for the two relevant energy levels. In the cases of thermodynamic equilibrium and of local thermodynamic equilibrium, the number densities of the atoms, both excited and unexcited, may be calculated from the Maxwell–Boltzmann distribution, but for other cases, (e.g. lasers) the calculation is more complicated. Einstein coefficients[edit] In 1916, Albert Einstein proposed that there are three processes occurring in the formation of an atomic spectral line. The three processes are referred to as spontaneous emission, stimulated emission, and absorption. With each is associated an Einstein coefficient, which is a measure of the probability of that particular know more at: http://www.astro.lu.se/Education/utb/ASTA21/pdf/Einstein%20coefficients.pdf https://www.physics.byu.edu/faculty/christensen/Physics%20428/FTI/The%20Einstein%20Coefficients.htm http://winnerscience.com/2012/03/13/einstein-coefficient-relations/ http://electron6.phys.utk.edu/qm2/modules/m10/einstein.htm https://www.physicsforums.com/threads/units-for-einstein-coefficients-in-stimulated-emission.315333/ http://th.nao.ac.jp/MEMBER/tomisaka/Lecture_Notes/StarFormation/3/node51.html http://web.ift.uib.no/AMOS/nazila/las/node2.html https://www.eng.fsu.edu/~dommelen/quantum/style_a/nt_einab.html -~-~~-~~~-~~-~- Please watch: "#CHARACTERSTICS OF LASER LIGHT || ENGINEERING PHYSICS ||" https://www.youtube.com/watch?v=5YALFqoK-N8 -~-~~-~~~-~~-~-

#pumpingscheme#lasersystem#laser#physics#Appliedphysics2 #Lastmomenttuitions #lmt This is about Application of Laser in Laser in Applied Physics 2 Credits to Nelson Dsouza - https://www.instagram.com/nelson_dsouza98/ To get the study materials (Notes, video lecture, previous years, semesters question papers) Join Our Community : https://lastmomenttuitions.com/lmt-community/ Applied Physics 2 Full Course - https://bit.ly/2kNy0UP Semester 01 - Applied Physics 1 - https://bit.ly/2lRbElo Engineering Mathematics 1 - https://bit.ly/2lUPezA Applied Chemistry 1 - https://bit.ly/2kAOAY2 Engineering Mechanics - https://bit.ly/2kNxjuH Basic Electrical Engineering - https://bit.ly/2VPQlyW Semester 02 - Engineering Mathematics 2 - https://bit.ly/2kASuQG Applied Physics 2 - https://bit.ly/2kNy0UP Engineering Chemistry 2 - https://bit.ly/2kAtWr3 Engineering Drawing - https://bit.ly/2maYwHV Structured Programming Approach - https://bit.ly/2kNxKVR Exclusive Courses : Engineering Mathematics 03 (Video's + Handmade Notes) - https://bit.ly/2GaM8yY Aptitude Preparation (with tips & tricks + Notes) - https://bit.ly/2kmlyLA Like & Comment Your Feedbacks Share this with your friends, so that they can prepare too! Connect us : Instagram : https://www.instagram.com/lastmomenttuition/ LinkedIn : https://www.linkedin.com/company/last-moment-tuitions/ Technical & Placement Preparation : Interview Series - https://bit.ly/2ki9U4l Python Zero to Hero: [Web+ML]+ Mentorship - https://bit.ly/2SIztMP Python Bootcamp for Beginners - https://bit.ly/2RJDwYu Complete Machine Learning Course with Python [Hands-On] - https://bit.ly/3hivTTS Python Zero to Hero Covering Web Development and Machine Learning + [Capstone Project From Scratch Included] - https://bit.ly/3uDdmVT Accelerated Machine Learning Using Python - https://bit.ly/3gc6URr Arduino (Beginners) - https://bit.ly/2mj7dAb UML Diagrams - https://bit.ly/2mj54od SQL (Beginners) - https://bit.ly/3gcLoKn6

population inversion of laser population inversion The condition of having enough excited or high-energy states distributed in a material that a chain-reaction of stimulated emission can occur. Lasers, for example, need a constant power source that maintains population inversion in order to generate radiation continuously, since each stimulated emission reduces the population of high-energy states. See also stimulated emission. In science, specifically statistical mechanics, a population inversion occurs while a system (such as a group of atoms or molecules) exists in a state in which more members of the system are in higher, excited states than in lower, unexcited energy states. know more at https://en.wikipedia.org/wiki/Population_inversion RELATED TAGS : population inversion population inversion laser population inversion and laser action population inversion animation population inversion in semiconductor laser population inversion youtube population inversion and stimulated emission population inversion in hindi population inversion and pumping population inversion in laser animation population inversion and metastable state population inversion by pumping population inversion definition in physics population inversion diagram population inversion definition inversion de population population inversion explanation population inversion helium neon laser population inversion in laser population inversion in laser action population inversion in laser ppt population inversion in laser physics population inversion in laser definition population inversion in physics population inversion in laser diode population inversion laser diode population inversion laser action population inversion meaning in urdu population inversion meaning in hindi population inversion nmr population inversion of laser population inversion physics population inversion wikipedia what is population inversion -~-~~-~~~-~~-~- Please watch: "#CHARACTERSTICS OF LASER LIGHT || ENGINEERING PHYSICS ||" https://www.youtube.com/watch?v=5YALFqoK-N8 -~-~~-~~~-~~-~-