# Tag Info

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There are many reasons why highly monochromatic light, such as that emitted by a laser, is useful for delivering a large amount of power to a small spot. First of all, incoherent light sources such as a lamp are extended sources which means that they are emitting light from a piece of material which takes up a finite amount of space. When focusing this ...

7

A typical "hobbyist laser cutter" with about a 50W power rating won't get you very far cutting metal except for metal foil, but there is no big deal about cutting up to 1 inch thick mild steel plates or tubes with a few kilowatts of laser power. There are plenty of videos on YouTube. Basically, you need enough power to cut quickly before the (high) thermal ...

6

Yes, other electromagnetic radiation can be focused, and routinely is. Basically, everything up to x-rays can be focused relatively easily. Once you get to energies so high that they go right thru most material, using these materials to focus such rays gets tricky or impossible. For example, I don't think we know of a way to focus gamma rays. On a cosmic ...

6

You might be interested to learn that not only are there microwave (and IR, and X-ray ... ) lasers, but that some of these "devices" can even occur naturally in gas nebulae in space. From the wikipedia article on Megamasers, A megamaser is a type of astrophysical maser, which is a naturally occurring source of stimulated spectral line emission. ...

5

Why this is hard One micron is on the border of what is theoretically possible. You cannot create a parallel ray at this scale. One micron is almost as small as the wavelength of the light you are trying to focus, so the usual rules of optics don't apply. Lasers normally produce what is known as a Gaussian beam, and they have a distinctive shape. You can ...

5

The 10/100/1000 refers to the transmission rate in megabits per second = millions of bits per second. Also may be shown as Mbps or Mb/s. 1000 Mb/s is a data rate typically achieved by modern LAN interfaces. 10 and 100 mb/s are the maximum rates achieved by older standards. A 10/100/1000 label is indicating that the device operates at the 1000 Mb/s rate ...

4

First is power those cutting lasers usually make relatively small cuts and take quite a bit of power and time. Scaling that up means waiting for a few decades to move a few meters if you can't get more power. Second is conservation of mass. All that rock has to go somewhere. If you use a laser it will evaporate. No-one wants to be breathing metal fumes in ...

4

You want a wavelength meter if you have one or otherwise a spectrometer. In more detail: A wavelength meter uses an interferometer to measure wavelength. It can measure wavelengths very accurately. A spectrometer measures a spectrum, that is intensity vs wavelength. The wavelength at the peak intensity is what you are looking for. A spectrophotometer is ...

4

Pulsed lasers release their energy in very short pulses which can have incredibly high peak powers. A run-of-the-mill nanosecond laser will have a peak power in the multi-kilowatt range while a femtosecond laser can easily reach into the megawatt range. In contrast, CW lasers generally do not reach power levels in excess of a few hundred Watts. When these ...

3

CO2 lasers cannot be coupled into standard silica-based fibres, because these fibres absorb light longer than 2.1um. You could use hollow silica fibres, but they are quite recently developed, so might be expensive. Otherwise I‘d just go with the standard approach of free propagation over mirrors OR use a solid state laser which can be coupled into standard ...

3

You are apparently asking about the Xerographic process, such as used in original copy machines and now in laser printers. The process works by charging up the surface of a cylinder (the drum) to a high voltage. The drum then rotates so that any parts of it that are charged pick up black particles, called the toner. Then a piece of paper is pressed ...

3

There are eye-safe lasers, both in the visible and IR. For your detection system, make sure you understand the power required for your target (receiver) to register a hit. Pretty much any commercial diode laser will have a small enough divergence (assuming you include a collimating lens) that point-spread over 150 m is minimal. However, you also need ...

3

Accuracy will vary a lot depending on what you are interested in. At the simplest level you are limited by the layer thickness, which is in the $20-100~\mu m$ range. This places a limit on the accuracy of the dimensions that can be achieved in the z direction. Theoretically you can achieve very high accuracy in x and y, but in reality you are limited by the ...

3

This is just an addition to the answer of Chris Mueller. When you think about lasers, you always think about an aperture with lot of mirrors, lenses and optics in general. Lets say that you manage to create a focused (wide spectrum) beam at one point, now you want to bring it to the point of application. With a wide spectrum it won't work well, as the beam ...

3

Conversion from the diode wavelength to the fundamental wavelength is generally a highly efficient process. Conversion efficiencies in the high 90 percent range isn't unheard of for 1064 nm generation, which is the fundamental wavelength of the green laser. Conversion to 946 nm, the fundamental wavelength of the blue laser, can also be highly efficient but ...

3

Hair is mostly transparent to ultrasonic, so this is still the reliable&convenient approach - any EM spectrum readouts (3D, video, laser) will be completely falsified by hair. You just need a narrow cone ultrasonic sensor - one with readout area restricted to top of the head. It's not something to be found in robotics/industrial equipment supplies, but ...

3

Its not hard- it bends the idea of what a laser is. Lasers have a single (or very narrow) wavelength of light emitted. There is no "white" wavelength- its just what your eye perceives from a (relatively) full spectrum of wavelengths. This is generally considered by the scientific community to be an advantage, not a disadvantage. You can do many cool things ...

3

The full letter is here: https://www.nature.com/articles/nature25176 They have 4 lasers: an RGB beam (3 lasers) that provides colour and an invisible 405nm beam that traps the particle. The RGB beam is pretty self-explanatory: you shine a beam of the colour you want the line to be. The trapping beam is more complicated, by using lenses with particular ...

2

I would just like to add, in addition to the other answers regarding the EM spectrum, that anything that follows the wave equation can be focused because all of the principles of constructive and deconstructive superposition apply. Things outside the EM spectrum that follow the wave formula include pressure waves (when focused, commonly referred to as ...

2

From the comment of @Dan and the linked Wikipedia article on masers: When the laser was developed, Townes and Schawlow and their colleagues at Bell Labs pushed the use of the term optical maser, but this was largely abandoned in favor of laser, coined by their rival Gordon Gould. In modern usage, devices that emit in the X-ray through infrared portions of ...

2

Since you mentioned "pilot," I'm going to guess you're looking for a way to block laser pointers from distracting airline pilots. It really should be sufficient to use the same thing used in laboratories, i.e. goggles which physically attenuate at and near the laser wavelength. Despite that patent's claims, I'm skeptical that their grating system will ...

2

The "laser device" you're looking for is called a Laser Tachometer, though other illumination sources will work. I have had good success with devices from Monarch Instruments. Specifically the ROS-P line of optical sensors (I see they have a laser version ) and the PLT200 Pocket Laser Portable Tachometer. The laser devices do work very well in more ...

2

As you change the relative arm lengths of a Michelson interferometer, the transmission (or reflection) coefficient of the interferometer ranges from $T=0$ to $T=1$ for coherent light, but, if designed properly, will always have a transmission of $T=0.5$ for incoherent light. If we define the length of the two arms of the Michelson to be $L_1$ and $L_2+\... 2 Of course, a lens with a short focal length can be used. The easiest way is to take the standard lens that comes with most laser pointers and move it a bit closer to the laser crystal. If you want the beam waist of the output beam to be exactly at the lens aperture, then you'll have to do a bit more work and find a suitable microlens. For a beam with 1 deg ... 2 If you have one convex and one concave lens, you can effectively make the laser beam smaller and more concentrated while still having a parallel ray. I believe it's called a galilean lens. It would take some effort to place them accurately that you have a width of only 1um though. If it's concentrated enough (which it certainly is if converged to 1um) it can ... 2 No, it is not possible to modulate the wavelength of a laser. The particular wavelength of light is determined by the amount of energy released when an excited electron drops to a lower orbit, which in turn is defined by the specific glass/crystal/gas used in the laser. Even if you could design some sort of mechanism to swap in/out different emission media ... 2 If I'm understanding your question correctly, you are asking how you can build a functional laser interferometer. That is a pretty complex topic and impossible to cover in detail in a single answer. I'll however point you to Sam's laser FAQ, which is an excellent resource and has a few thoughts about building such from a CD-ROM drive: http://www.repairfaq.... 2 Photo-lithography is expensive and is generally more useful in etching away some surface layer than drilling holes. Generally the light source doesn't actually remove material but selectively cures a coating on the surface which masks off teh pattern to be etched. Compared to weaving which was one of the first ever processes to be mechanised and automated ... 2 There are a number of things to deal with. The plexi has a reflectivity of around 4% per surface (see, e.g. this spec sheet , but minimal absorption. So pure loss is 8% (but will increase dramatically if you tilt the plexi sheet) However, if you've placed the sheet between the lens and the focal point, you have not only moved the focus (see "equivalent ... 2 The equation you are looking for is $$I(z) = (1-R) \cdot I_0 \cdot e^{-\alpha z}$$ where$I(z)$: intensity of the laser beam after the distance$zR$: reflectance of material$I_0$: intensity of laser beam on the surface$\alpha$: absorption coefficient (NOT the same as absorptance)$z\$: thickness of the material When you plug the thickness of the ...

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