Laser Definition and 1000 Threads

When you look at the spot of light made by a laser pointer why does the light have a shimmering grainy look?

I am thinking about a possible experiment, and would like to measure the temperature of gas in various places inside of a glass enclosure. Is it possible to use an infrared laser to this? Thanks

Thought Experiment 1: I shoot a laser into space for one second. Just before I let off the trigger, the face of the beam is ~186,000 miles away. What happens to the beam when I let off? Does it instantly cease to exist? Does the tail compress into the stopped head and go poof :)? Does that...

Is broadband field, a wave that contains a range of wavelengths? I can not find a good definition for it

In thinking about what it would take to make a feasible invisibility cloak or holographic disguise or perfect hologram room, I've imagined something that works like this: A light beam "image" is projected onto a device designed to refract or reflect it in all directions, but only 1 color in any...

Homework Statement You shine a powerful laser onto to the surface of the Moon from Earth (Earth-Moon distance is 384,000 km or 3.84E8 m). About how fast must the laser pointer rotate (in degrees per second) for the spot on the Moon to move with velocity v>c? Does this violate Special...

Homework Statement Homework Equations 2. (b) I didn't understand how can I find the app. wavelength The Attempt at a Solution I tried : the electron move over λu with velocity β so the wavelength is λ≈λu /β but its not the right answer. my lecturer told me I should...

I am not sure this is the right place where I should post, I hope I've chosen the right section. I'm studying laser's fundamentals on Svelto's "Principles of Lasers". Here I find the description of a generic four level laser by means of rate equations; it can be represented like this: (first...

Hi, I am new to the lasers/optics world and I just started working with a nanosecond laser. I am supposed to use this laser to run some test (thermal writing) on some samples. I have noticed that laser tends to not deliver the precise amount of energy in each pulse, and this hugely affects my...

Hi! I want to conduct an experiment to investigate the effect of sucrose concentration on refractive index using a laser pointer however I would like to complicate this experiment as this is just a simple how x affects y experiment. It may also seem to straight forward as obviously higher...

I am wondering what causes warping in laser sintering? Can someone explain the mechanism to me? For a single layer, which direction will it warp in? (towards or away from heat source), and how big is the deflection is it usually?

Hi! a very basic question that probably has a simple answer: would it be possible to trace a laser moving over a generic surface such as a wooden floor with an IR camera? The idea would be to calculate relative movement based on that... If I'm not clear enough feel free to follow up with a...

Three questions, In a femtosecond laser, or any laser for that matter, how is a pulse generated from noise? how do the phases match up? we use modulation for this? if so, what kind? Also, how does a laser get self mode locked when you push it or 'kick' it from the back? what does this...

what are the different mechanisms that cause plasma emission?

Homework Statement An intergalactic cruiser is approaching a hostile spacecraft . Both vehicles move at a constant velocity. The velocity of the cruiser relative to the spacecraft is vCS=+0.7c, the direction to the right being the positive direction. The cruiser fires a beam of laser light...

I am somewhat confused about the connection between divergence and solid angle for a beam. I know individually what each term means... but I'm confused as to how (or even if) one can calculate the solid angle of a beam, given the divergence. I have some notes from a previous lecture series I...

In ARPES measurements, people say that the laser light cannot cover a wide area of momentum space whereas the synchrotron light can (M. Hashimoto et al., Nat. Phys. 10 (2014) 483). Why is that? (Figure 3a in the paper is a combination of laser and synchrotron data to plot spectra along the...

I was wondering if I could create plasma inside my own apparatus using a laser pointer and nitrogen..

Not really sure if this should go here or in technology, but it's a physics class sooo... we had to build a device to measure the power of a laser with an output of around 10mW or less. I went with a differential gain amplifier using 2 thermistors, one of which is kept at ambient...

Hi there, I'm looking for some information on the current limits of the beam width of currently available lasers. I'm less interested in experimental setups that are not on the market yet, but I suppose if one of them is markedly different it would be interesting to know. Specifically...

Hi, I'm new to this forum, and I need some help with this. I want to determine the polarization of a laser beam, that is, the type of polarization (linear, elliptical), the angle of polarization (if it is linear). Then, I want to represent this mathematically. I used some linear polarizers to...

Hi, I've attached the problem that I'm trying to solve. I've also done the manual calculations to calculate Ithreshold. I'm not very good with MATLAB and I need MATLAB code for laser rate equations and I also need to plot LI characteristic of the laser. I_th=qV/(η_i τ) N_th=qV/(η_i τ)...

Hi, My question is how do do laser interferometers measure distances of more than one wavelength? I know they rely on phase difference to calculate distances but phases only differ at 180 degrees at max so how do interferometers factor in going over 180 degrees in phase difference to...

Hi all, I'm implementing a computer vision system with a near-infrared laser and a NIR bandpass filter. It shines a laser on things and looks for a reflection. I'm getting a bunch of interference from sunlight and was thinking of using a polarizing filter to cut some of the sunlight out...

Hi, is there anyone familiar with rate equation solving using Matlab? I need help on this

Homework Statement I want to calculate the average force and acceleration on an sodium atom, if a laser bundle shines on it which has I>>>> I(sat). I(sat) is the saturation intensity of the 589nm 3s-3p transition in sodium. 3p lives 16 ns Homework Equations c = 3 * 10 ^ 8 m...

Other than Rayleigh and to a lesser extent Mie scattering what other mechanisms might exist that would contribute to backscatter for a high energy laser propagating through the lower atmosphere?

Homework Statement hello i need a pdf or a homepage where i can get all symbols (variables ) for Laser questions for example λ=Wavelength v=frequency ω=Beam waist Q= quality factor etc. i have a problem understanding some questions because i don't know which symbol they...

Hi Every one, I measured optical output power from both laser facets, front facets emits 120 mW and back facets 10 mW. Assuming front facets reflectivity of 30%(for cleaved facets). What will be the reflective of back facets? Please suggest formula and reference this problem.

I am working on a new concept design and would like some suggestions on which Lasers(s) would be most appropriate for heating a high pressure vessel for producing steam. The concept requires very quick steam generation but heat can not be excessive enough to harm the vessel being heated. As a...

Homework Statement In an experiment a laser beam is focussed on a sample by a lens. The sample has micro structures spatially separated by 5 microns. In the experiment, each micro-structure has to be studied individually using the laser, so that illumination of two or more adjacent...

I've heard of frequency doubling but is wavelength doubling a thing? If so, how efficient?

As far as I understand, when forward biased voltage applied, electrons from N diffuse to P, then recombine. Since energy gap between conductive electron and hole is const => only certain wavelength photons is emitted. In gaseous lasers for example you need to gain a populational inversion...

Hi guys, sorry new to this, I'm looking to build a simple laser using magnifying glasses, lenses and a laser pointer. How would I go about it and can I get away with using the pointer or do I need a laser diode?

I've been searching for a while, but all I seem to find is information about how it's illegal to sell laser pointers to minors in New York City. That and I find some information on what else is illegal to do with a laser pointer in NYC (pointing at vehicles, officers, etc.). There's a lot of...

Hello All, Apart from using undulator or wiggler are there any big difference between synchrotron radiation and FEL? Because I notice it looks similar. In both case electron is forced to travel like a sine wave...and synchrotron radiation is produced.. Also what is the difference between...

Homework Statement 1. Vertically polarized light from a helium neon laser passes through a linear polarizer with its axis of polarization oriented 15° from the vertical axis. Assuming no absorption or reflection: (a) What percentage of the light will be transmitted? (b) What will be the...

1. Won't the electrons get knocked out of the atom during the pumping action instead of just getting excited to higher energy level in LASERS? 2. why doesn't the electron in meta stable state(higher energy state) go to much higher energy level during STIMULATED emission instead of losing energy...

I'm developing a scanner that uses a laser for edge detection. It will be mounted on a hexacopter that will traverse a short distance through a cave/tunnel system and produce a 3D image. I'm still researching on ways to process this data but I'm thinking of using a edge detection algorithm in...

Homework Statement Two laser beams, one of wavelength 633 nm and intensity I1 = 4.00x106 W/m2 with a circular beam profile D1 = 1.33 mm in diameter, and one of wavelength 442 nm and intensity I2 = 4.00x106 W/m2 with the same circular beam profile are fired, crossing at an angle of θ = 45°...

I am doing a final year project, my Prof gave me 2 prism. He wants me to do so: A white laser is shot on a prism producing a visible light spectrum, use another prism to converge the spectrum back into a laser. For me, it is theoretically impossible and I tried to convince him that it...

I have been trying to write the mathematical simulation for this device but unfortunately I found no clue to start with . the simulation should be starting with the Gaussian beam equation of the laser source and then the vibrations in the glass pane cause the window to flex, changing the...

does it mean extract electrons from the out put of laser beem

Laser Interferometer--Need advice/opinions about design. Hey Everyone, I'm in the midst of designing a laser interferometry system to measure flatness and to level a stainless steel plate. It's a really simple design and I'm wondering what the drawbacks are for this type of system. I'm just...

Hello. I have a bachelor degree in physics and I'm an embedded programmer now. I would like to engage in scientific activities, but I can't choose the area: Laser Physics or Artificial Intelligence (Machine Learning, Pattern Recognition...). I heard opinion that artificial intelligence - the...

Hello, I have a quick question about the distinguishing features between a 'monochromatic light source' and a laser. In my notes on wave optics, I have a diagram of monochromatic light being diffracted through a single slit, to produce a coherent wave formation that then hits a double slit...

I'm trying to focus a 3mm diameter laser beam (527nm) to a 0.3mm spot size. According to this online calculator I need a +500mm focal length lens and a -50mm FL lens separated by 450mm. However, in practice this did not produce a focused spot. I'm assuming this calculator has made some...

Homework Statement In front of a long, straight, white wall a laser is hanged. Laser is parallel to the wall when we decide to rotate it with constant angular velocity for ##\pi ## so that the laser spot travels over the entire wall. The duration of the turn lasts just as long as it takes for...

Hello, I am trying to recreate the double slit experiment using ordinary light, i.e. sunlight or light from a light bulb or torch. I do not wish to use a laser for various reasons. I have experimented with the distance, spacing, and width of the slits, but I cannot get an interference...

What filters are to optics, could gas be to a laser?