Elastic Instabilities of Slender Structures. Mannini C, Bartoli G, Borri C, Borsani A, Ferrucci M, Procino L (2.
![]() Recent developments in measurement and identification of bridge deck flutter derivatives. U. Peil, ed., Wt. G Berichte Nr. 1. Windingenieurwesen in Forschung und Praxis, Dreiländertagung D- A- CH, Braunschweig, Germany, 1–1. Sam's Laser FAQ - Items of Interest. Sam's Laser FAQ, Copyright © 1. Samuel M. Goldwasser, All Rights Reserved. I may be contacted via the. Sci. Electronics. Repair FAQ. Email Links Page.Back to Sam's Laser FAQ Table of.Sub- Table of Contents. Nintendo Dog Ds Download Roms Nintendo . Introduction to Items of Interest. Laser Power, Photons, How Much Light?, Beam Profile. Laser Power Meters. Gain, Stability, Efficiency, Life, FB versus DFB Laser. Pulsed/Average Power, Q- Switching, Ultra- Short Pulse Lasers. Laser Optics. Laser Wavelengths. Laser Visibility and Color. Laser Beam Spectral and Other Effects. Speckle, Coherence, Stability, Polarization, Noise. Beam Collimation, Divergence, Focus. Laser Beam Profiles, Cleanup. Laser Beam Splitting and Combining. Diffraction Gratings, Pattern Generation. Modulation and Deflection. Other Types of Lasers and Related Devices. Laser Myths and Fantasies. Laser Humor. Back to Sam's Laser FAQ Table of. Back to Items of Interest Sub- Table of. This chapter represents a potpourri of general laser information. Basically. when something interesting and relevant to lasers shows up on one of the. USENET newsgroups or elsewhere, it gets stuck in here. Therefore, given the. As always, I welcome contributions to help expand quantity and. Topics not covered here may often be found in the chapters on specific lasers. For example, information on mode structure and coherence length is in the. Helium- Neon Lasers, specifically. Longitudinal Modes. Here are meanings of a few acronyms and abbreviations commonly used with. More will be added as I think of them or am reminded. For the most part, I explain such terms when first used in a given section. AR - Anti Reflection (coating). The coating on an optical surface to. This produces the blue or purple. Both surfaces of the OC (see below) mirror of a laser may be. Access our countless collection of FREE quality PowerPoint Presentations (PPTs) prepared by elites, capable of providing simplified insight to most advanced & complex. AR coated (though you cant detect this on the inner surface which also has. OC coating). HR - High Reflector (mirror) or High Reflection (coating): The totally. HT - High Transmission (Coating). Probably similar to AR coating (this. OC - Output Coupler: The optic that couples the beam out of a laser. Usually, this is the partially reflecting output mirror of a laser. The OC reflectivity and spectral response will depend on the type and size. However, for. some lasers like green DPSS types, the optic from which the beam emerges. HR) mirror for the fundamental wavelength and the actual. However, I still consider the mirror. Dielectric mirror or coating - A surface built up from multiple. These are also called 'dichroic'. Dielectric mirrors can have nearly perfect (1. Note that throughout this document, I use the term 'dielectric' in reference. Nowadays, it apppears as though. CW - Continuous Wave. A laser that operates with a constant output. The opposite is a pulsed laser which produces short. A Quasi- CW laser. W - Watt. A measure of power (electrical, optical, mechanical) equal to. W is kilo. Watt (1. W, m. W is milli. Watt. (1. 0- 3. W, u. W is micro. Watt (1. W, n. W is nano. Watt. A few on- line references with just a bit more extensive information can be. And, of course, general on- line encyclopedias like. Since laser and optics deals with units on scales from the very small to the. I couldn't figure out a better place to put them, here are. Source: "The NIST Reference on Constants, Units, and Uncertainty".). Name Symbol Factor. M 1. 06. giga G 1. T 1. 01. 2. peta P 1. E 1. 01. 8. zetta Z 1. Y 1. 02. 4. The "u" should really be the Greek symbol for "micro" but I'm too lazy to use. HTML code. They make a big deal out of the special case of kilogram which is the only SI. So, the SI police will come get you if you write something. Luxpop has calculators for a variety. Gaussian beam propagation. Back to Items of Interest Sub- Table of. Laser Power, Photons, How Much Light?, Beam Profile. Any given laser - be it a He. Ne, argon ion, CO2, or other CW laser; or a pulsed. Nd: YAG, Ti: Sapphire, or excimer, will have two, maybe three. The manufacturer's power rating based on model. This is the one you find. For He. Ne lasers, there is a single rating since these are generally. Example. (Spectra- Physics He. Ne laser model 1. He. Ne laser): 5 m. W. For CW lasers which have variable output power like argon ion and CO2. Example: See the chart in the section. Argon/Krypton Ion Laser Tube Life. Similarly, pulsed lasers like flashlamp pumped Nd: YAG may have a chart of. However, note that pulse- to- pulse variations of 1. The actual measured power output at the time of manufacture. This value. or chart may be provided with a certification document or hand printed. As the laser gets. Example (for the Spectra- Physics model 1. He. Ne laser): 6. W. The CDRH sticker rating. This is the MAXIMUM power rating for the. CDRH designation). However, a much higher. A He. Ne laser produces its maximum output power at the nominal operating. Example (for the Spectra- Physics. He. Ne laser): 1. W Max, Class IIIb Laser Product. Where the output power of a laser increases with increasing tube current. Unfortunately, when people offer used or surplus lasers for sale, they often. CDRH sticker rating (a) because it is the only one that may be. HIGHEST and sounds more. See the section: Buyer Beware for. Laser Purchases. Here are those definitions you always wanted! Portions from: Dr. Mark W. Lund (mlund@moxtek. A Lumen is a quantity of light, the same kind of unit as a watt, but. If you are looking at the specification of a light source Lumens are the. A Lux is a lumen per square meter, which we might call illumination. It is how much light that. A Nit is a lumen per square meter per steradian, which we might call. If a Lux of illuminance. Nit of luminance. A Candela is a lumen per steradian. It is used for "point" sources. Put another way, Candelas are a measure of luminous intensity through an. For an isotropic. Candela is equal to 1 lumen per steradian. There are 4 x pi or. A 1. 2. 6 lumen. isotropic source would then produce 1 Candela. This doesn't really apply to. However, it is still possible to define the Candela. So, if your laser put out 1 lumen over. Candelas would be 1. Candelas. I (Mark) was at one time a true expert on photometry and radiometry and I still. LED with another because every company. Warren Smith gives an admirable discussion of photometry in his book "Modern. Optical Engineering". Or, check out the Lighting. Design and Simulation Glossary for definitions of these and other related. A Radiometry versus. Photometry FAQ by: James M. Palmer (jpalmer@azstarnet. FAQs are ever fully developed!). PDF Version also. From: Ian Ashdown (byheart@direct. A foot- candle is a unit of illuminance, which is defined in ANSI/IES. RP- 1. 6- 1. 99. 6 (Nomenclature and Definitions for Illuminating Engineering), from. Illuminating Engineering Society of North. America as "The areal density of the luminous flux incident at a point on. In plain English, illuminance is the quantity of light arriving at a. The point does not have to be located. One foot- candle is equivalent to one lumen per square foot (where a lumen. A wax candle flame has a luminous intensity (or equivalently, candlepower). If you hold the candle one foot away from a. It will be 1/4 fc at. Brightness is a psychophysiological phenomenon that cannot be measured. The term "photometric brightness" used to refer to luminance, but. Let me rephrase that: it. There is an understandable but technically accurate description of photometric. From: Don Klipstein (don@misty. A lumen is defined as the "luminous flux" of 1/6. Terahertz, or a. wavelength of approx. One thing worth noting is that a. THz. monochromatic light.) Light of wavelengths other than 5. The number of lumens. I believe is very close to but not exactly 1). A "USA- usual" 1. A1. 9) light bulb. Lumens per watt is a measure of efficiency in converting electrical. Multiply this by the watts dissipated in the LED to. A typical red, orange, or yellow or yellow- green LED has a. A blue, white, or. A and gets . 0. 7 watt at 2. A. A candela is a lumen per steradian, or "beam candlepower". Actually. as mentioned above, the candela is a primarily defined metric unit. So lumens are. candelas times the beam coverage in steradians. Candelas are lumens. Ideally, that is - . So you may now be wondering what a steradian is. It is 1 / (4 * pi) of. To get steradians from the beam angle. Steradians = 2 * pi * (1 - cos (. NOTE: There are a few other expressions equal to this. Proving that. is homework for 1. So if you determine the steradian beam coverage and multiply that by. The beam is not uniform and it does.
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