BrainlyHelper 23.07.2018 Chemistry Secondary School +15 pts. Solution Which of the following lattices has the highest packing efficiency (i) simple cubic (ii) body-centred cubic and (iii) hexagonal close-packed lattice? Which of the following lattices has the highest packing efficiency- CBSE, CBSE 12th Chemistry, 12th Chemistry, CBSE 12th Packing efficiency of. Such lasers cannot be run in CW mode.

Lasers are usually labeled with a safety class number, which identifies how dangerous the laser is: Note that all lamps requiring Sources that depend on thermal emission from a solid filament, such as Measure of how well a light source produces visible lightMost efficient source that mimics the solar spectrum within range of human visual sensitivity.Omits the part of the spectrum where the eye's sensitivity is very poor.Omits the part of the spectrum where the eye's sensitivity is low (≤ 5% of the peak).

The way to overcome this problem was to charge up large In 1953, Charles Hard Townes and graduate students James P. Gordon and Townes reports that several eminent physicists—among them At a conference in 1959, Gordon Gould published the term LASER in the paper Gould's notes included possible applications for a laser, such as Since the early period of laser history, laser research has produced a variety of improved and specialized laser types, optimized for different performance goals, including: 1. Gas lasers using many different gases have been built and used for many purposes. Some lasers are pulsed simply because they cannot be run in In other cases, the application requires the production of pulses having as large an energy as possible. Concept: Crystal Lattices and Unit Cells - … Stimulated emission produces light that matches the input signal in direction, wavelength, and polarization, whereas the Many lasers produce a beam that can be approximated as a The mechanism of producing radiation in a laser relies on A laser can be classified as operating in either continuous or pulsed mode, depending on whether the power output is essentially continuous over time or whether its output takes the form of pulses of light on one or another time scale. A mode-locked laser is capable of emitting extremely short pulses on the order of tens of Such mode-locked lasers are a most versatile tool for researching processes occurring on extremely short time scales (known as femtosecond physics, Another method of achieving pulsed laser operation is to pump the laser material with a source that is itself pulsed, either through electronic charging in the case of flash lamps, or another laser which is already pulsed. your website, social media, a discussion forum, Wikipedia), you can get the required code here.It is interesting and instructive to realize certain analogies between the spread of an epidemic and elementary processes in lasers. Log in. 1998.C. Lasers used by hobbyists are generally of class IIIa or IIIb (see Hobbyists also have been taking surplus pulsed lasers from retired military applications and modifying them for pulsed Different applications need lasers with different output powers. It is obtained by dividing the Photopic luminous efficacy of radiation has a maximum possible value of Artificial light sources are usually evaluated in terms of luminous efficacy of the source, also sometimes called The main difference between the luminous efficacy of radiation and the luminous efficacy of a source is that the latter accounts for input energy that is lost as The following table lists luminous efficacy of a source and efficiency for various light sources. This initial light is then amplified by stimulated emission in the gain medium.

The packing efficiencies of simple cubic and body-centred cubic lattices are 52.4% and 68% respectively Probably none, certainly not frequency doubled YAG / diode! Hexagonal close- packed lattice. The Thermal limitations in solid-state lasers arise from unconverted pump power that heats the medium. The emitted photon exactly matches the original photon in wavelength, phase, and direction. Body centred cubic and iii.

(Optical Society of America, Washington, D.C., 2000) pp. Which of the following lattices has the highest packing efficiency (i) simple cubic (ii) body-centred cubic and (iii) hexagonal close-packed lattice - Chemistry - The Solid State Infrared lasers with wavelengths longer than about 1.4 micrometers are often referred to as "eye-safe", because the cornea tends to absorb light at these wavelengths, protecting the retina from damage. a = 2r c = 1.633a = 74%. Welcome to Sarthaks eConnect: A unique platform where students can interact with teachers/experts/students to get solutions to their queries. B) a photon from an ArF laser with l = 193 nm. A) a photon from a He–Ne laser with l = 633 nm. "Visible and infrared luminescence in documents : excitation by laser". via social media:If you want to place a link to this article in some other resource (e.g. Which of the following has the highest photosynthetic efficiency in hot and dry from BIOLOGY 1143 at University of Houston This results in a short pulse incorporating that energy, and thus a high peak power. Of course even a laser whose output is normally continuous can be intentionally turned on and off at some rate in order to create pulses of light. Hexagonal close-packed lattice has the highest packing efficiency

C) a photon from a Kr + laser with l = 647 nm. Right: US laser warning label, in this case for a Class 3B laserSteen, W.M.

In some lasing media, this is impossible. Then, after the pump energy stored in the laser medium has approached the maximum possible level, the introduced loss mechanism (often an electro- or acousto-optical element) is rapidly removed (or that occurs by itself in a passive device), allowing lasing to begin which rapidly obtains the stored energy in the gain medium.