Questions tagged [laser]

Light Amplification by Stimulated Emission of Radiation. A means of creating coherent light by either driving an atomic or molecular transition in an optical cavity or firing a beam of electrons through an undulator.

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Concept for an laser array projector creating speckles [closed]

I am at a very early stage of concepting an array projector for 3D measurements using stereo photogrammetry. The projecter shall introduce speckles into the scene, so there is always good contrast - ...
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Can actually a photosensitive diode detect particles travelling at 10 km/s?

I am working currently on cosmic particles detection and I was wonder, if according to Mie theory or maybe another kind of theory, if a particle of PM2.5 which travel at 10km/s and cross a laser beam ...
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How do lasers work if the phase shift from reflection is 180 degrees?

I am having a hard time wrapping my head around the phase shift that is imposed by reflection. I'm specifically thinking about things like visible light of off mirrors or RF reflecting off of silver, ...
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How to find the maximum velocity a particle can have to stop within a given distance

I have a set of particles moving with different velocities which are being decelerated by a laser. I have calculated the distances travelled by solving the differential $$dv/dt = F(v)/m.$$ The ...
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Does the manipulation of the Fresnel number and light intensity work?

I am currently a high schooler and am trying to find the intensity of the bright point in Arago's spot. I am trying to find some manipulation of equations to hopefully gather the intensity of the ...
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Power spectral density of laser intensity noise from a photodiode signal

I would like to get the power spectral density (PSD) of the laser intensity noise from a photodiode (PD) signal, which is picking off some light from a laser beam to be used in the process of Bragg ...
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Could I reflect a commercial laser off of the reflectors left on the moon by the astronauts?

Would an ordinary laser pointer reach the reflectors placed on the moon? I want to reflect a laser off of the moon. How powerful must my laser be?
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Laser on metal surface: What happens in terms of photons, plasmons, phonons and their interactions?

I'm trying to better understand what exactly happens when a laser beam hits a surface (apart from reflection). Say I have a thick gold surface (could be coated with gold nanoparticles if that helps) ...
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Collimating a cutting laser

I have a 450 nm, 5.5W laser from a cheap laser cutter. The beam focuses at about 20 mm away from the outlet rim of the laser unit's housing. I want to collimate the beam in order to be able to cut ...
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Can fusional atomic compression theoretically be achieved with a unidirectional compressive force? [closed]

In other words, is it theoretically possible to get an energy-profittable nuclear fusion reaction by simply slamming compressive force into some atoms from a single laser compressing from one ...
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What will happen when a laser which carries information passes through a glass?

I am currently working on my summer project. One of my tasks is to figure out what will happen when a laser which carries information passes through a glass, like how will the glass affect the laser(e....
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Calculating Zernike Polynomials from Image not Wavefront

Zernike Polynomials can be fitted to measured wavefronts to characterise the optical aberrations present in an image which can be corrected using adaptive optics such as a deformable mirror. For some ...
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UV-absorption capability of air

I am looking for an absorption chart for UV light with a wavelength of around 250 nm in air (ambient, no specific preparation). How much of a beam of this light would be absorbed per meter of path ...
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Could the phase relation between wavelengths in supercontinuum produce speckles?

Typically, if we use a narrowband laser for an optical setup to image something we observe a picture spoiled by speckles, coming from the laser spatial coherence. Let's say, now I will use a ...
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As a pulsar beam is a gaussian beam does its diffraction depend on its cross section area?

Some point lasers with cross section area of few milimeters have a range of several kilometers. There is a angle of diffraction or spreading out of the beam that depends on frequency of the beam but ...
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How does coherence of a light affect how we perceive a sample in a microscope?

First of all, does coherence of a light, which is used for illumination in a microscope, affect the sample, or the way we see/perceive it? I want to know what optical elements do I need to use if I ...
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Simulating Plasma Ionization Rate using PPT formula

I've used A.14 formula in the paper "Ultrashort filaments of light in weakly-ionized, optically-transparent media" to calculate the dependence of ionization rate in oxygen molecules in air ...
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Is there a reflection when light destrucively interferes on a surface?

Imagine the following setup: I have a coherent single frequency electromagnetic wave (laser beam) that is imaged on a surface. It is reflected onto a detector (photodiode). I can easily take ...
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Relation between total pulse energy and electric field of a THZ pulse

We've this relation between the total energy of generated THz pulse and the electric field of the THz pulse. $$J_{THz}=c\varepsilon_0\int [E_{THz}(r,t)]^2rdrd\varphi dt \quad\text{(eqn. 1)}$$ Where ...
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Ionization rate in femtosecond laser filamentation

The ionization rate in femtosecond laser filaments in air using 800nm central frequency and >100fs pulse durations is said to be mostly coming from MPI (Multiphoton Ionization). The intensities ...
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The use of Principal Component Analysis (PCA) in Spectroscopy [closed]

Greetings there fellow users. I am to prepare and give a seminar on Principal Component Analysis (PCA) in the subject of Laser Spectroscopy (aka solid state spectroscopy). Now i am quite comfortable ...
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How can I determine how much energy a sensor pixel can withstand before exploding? [closed]

I am trying to design a camera system to image a laser beam. I know the sensor is a Sony IMX226, and I have the data sheet for this sensor. The data sheet, however, does not list a maximum energy ...
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Pumping Nd:YAG laser with LEDs... would it work ? What would be the efficiency?

I find on Wikipedia that Nd:YAG absorbs mostly in the bands between 730–760 nm and 790–820 nm, and are pumped with flash tube or laser diodes. Couldn't it get pumped with normal near IR power LEDs (...
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Why some line lasers of power less than $\rm 1mW$ is brighter than that rated for higher power?

I want make a line laser that uses 1mW power and should be visible at a distance of 10 m. I have a locally available laser module of 5mW which barely reaches 5 meters whereas Bosch GLL5-50X claims to ...
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How to Model Chirp in Laser Pulse

I'm trying to model a chirped pulse with Python using the following form: $$ E(z,t) = cos \left( \omega_0 \cdot (t-z/c) + \beta (t-z/c)^2 \right) \cdot exp \left[ - \alpha t^2 \right] $$ From ...
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What is the principle behind diffraction?

If we shine a green laser on a wall in a dark environment, we would observe a bright dot in the middle. Now, if we fix a grating just in front of where the laser is held, when the beam strikes the ...
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Collimating and expanding a laser beam

I have a divergent laser beam of diameter = 4 mm and divergence = 2 mrad, both measured at 60 cm from the laser output. I want to collimate it and also expand it to 5 mm, while keeping it collimated ...
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How to achieve uniform gaussian profile? Beam profile has grainy/multimode pattern, EO says it's due to different emissivity of each phosphor atom

I'm required to make a jig that measures the divergence angle of a collimated beam. The setup is straightforward as shown below. The single-mode fiber optic cable, collimator & NIR camera are the ...
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Why does Cadmium have a large natural linewidth? And why does this make Zeeman shifting more difficult?

I am reading through this paper and am unable to find information on the following statement: "Since Cd has a large linewidth, high magnetic field gradients are required to shift the Zeeman ...
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If the range of a laser depends on its crossection perimeter does it mean that a wider beam would reach much longer distances?

If the range of a laser depends on its crossection perimeter does it mean that a wider beam would reach much longer distances? Let pressume that we can construct a 1m wide laser beam and as we know ...
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Relation between the lifetime of gain medium and laser frequency bandwidth in $\rm HeNe$ laser

When I am studying about Spiking phenomenon of lasers, I found this "spiking occurs for lasers where the upper-state lifetime is much larger than the cavity damping time. Gas lasers often ...
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Can this laser cofiguration be used to penetrate armoured bodies?

I asked the same question before but as it was stated as unclear I hope that with several corrections the question is more clear now. As the question is more theoretical than engineering I posted here....
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Maximum Intensity for Gaussian Beam

So I wanted to find out the maximum intensity for a Gaussian beam for a given aperture $D$ which is valid for near and far field, as a function of distance $z$, wavelength $\lambda$ and initial power $...
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How to predict the time domain of pulse from an amplitude mask in frequency domain?

I am studying ultrafast spectroscopy (pump-probe) and I know that ultrashort laser pulses are used for the pump and probe. These pulses often contain multiple frequencies (i.e. polychromatic pulse) ...
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Are laser diffuse reflections really so dangerous?

Class IV lasers are lasers with an optical power higher than 500mW, and for these lasers "even diffuse reflections can cause permanent eye damage". Well, I would like to understand how this ...
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What lenses are generally used to focus a beam of light into a horizontal line?

I am trying to find out more about the inner workings of a laser scanner I'm using to map objects. In this case the technical details are quite hard to come by. The laser scanner generates a beam of ...
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Difference-frequency-generated (DFG) spectral width

If we have two laser beams with central wavelengths $\lambda_1$ and $\lambda_2$, (one with a spectral width of $\Delta\lambda_2$ and one with negligible spectral width), interacting in a non-linear ...
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Sources about $M^2$ parameter for lasers

I am trying to find some sources about the $M^2$ parameter for lasers, I have already looked for that in 3 of the following books: laser-electronics-prentice-hall-1995 OrazioSvelto PrinciplesOfLasers ...
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Fading law of the peak value of the E-field in a laser beam

I am not used with the theory of lasers, and feel uncomfortable with it. According to Wikipedia, the electric field of a gaussian beam can be given in phasor notation by $${\mathbf E(r,z)} = E_0 \, \...
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What happens when bending laser light in a liquid stream smaller than its wavelenght?

When you point a laser into a water stream it bends with the waterstream and exits at the end. It bounces constantly from the "virtual wall" till it reaches the end of the stream. Now if the ...
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Why do lightbulbs produce any light, when the light they produce is incoherent? [duplicate]

First let's talk about lasers. A simple three level laser produces coherent light from stimulated emission, and incoherent light from unstimulated emission. I have been told that the intensity of ...
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Could bremsstrahlung provide evidence that a Black Hole (BH) forms the underlying geometry of the electron?

There are several proposals that model electrons as BHs. For example, A. Burinskii proposes a spinning soliton on a Kerr-Newman BH geometry (enhanced to an MIT bag model in “New path to unification of ...
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Diode laser optics - How to shape the beam of a Diode bar?

I have a 40w, 808nm, CS mount diode bar. I would like to build a something similar to a Rofin Dilas laser diode. How to choose the optics, measure distance, focus the beam into a fiber coupler? I came ...
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Is it possible to create a laser pointer with adjustable beam width?

Is it possible to create a (line) laser pointer with adjustable beam width? I mean instead of having a dot laser pointer, create one where one may press a button to switch from 10m line beam to 5 m ...
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Vertical peaks in single slit diffraction pattern

I have the output from a single slit diffraction experiment using a HeNe laser (632.8nm), the diffraction grating is placed vertically so you expect to see only horizontal diffraction peaks in the “...
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Use standing wave to understand mode locked laser

Recently when I was trying to explain the principle of kerr-lens mode-locked laser, however I find that I don't even understand it myself. People around me always say the longtitude modes of the ...
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Estimate laser diode beam quality from datasheet

I want the estimate the minimum divergence angle that can be obtained when collimating the beam coming from a laser diode. For this I intent to use the following equation from https://www.rp-photonics....
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Terahertz generation in semiconductors after ultrafast laser excitation

Terahertz can be generated by means of the photo-Dember effect, where a short laser pulse generates electrons and holes. These charge carriers have a different mobility which gives rise to a dipole ...
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Astigmatism in bow tie cavity

I am a bit confused about how to account for the astigmatism in a bow tie cavity. I did the math for the resonant frequency of the tangential and sagittal direction of a Gaussian beam, and I got in my ...
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What does $\partial_{k_\mu}$ mean on the Simon Laboratory site at Stanford University? (condensed matter physics and quantum optics)

I realize this is a strange question, but I have come upon the Simon lab site a lot, and that symbol or motto of theirs is everywhere, and I am just wondering if it means anything..... http://simonlab....
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