All Questions
48
questions
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9
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Does the beam image invert on each round-trip through a hemispherical laser cavity?
When one creates a hemispherical laser cavity, using one flat and one concave mirror, does the beam image invert each time it makes a round trip? I know when passing through the focus of a lens/mirror,...
1
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0
answers
47
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Are there any nonlinear crystals or other transparent materials that can produce anti-Stokes, phase matched, frequency shift of laser light?
While some nonlinear crystals can convert incoming laser light into harmonics, thus for example doubling the light frequency, are there any crystals or other transparent materials that can reduce the ...
- 240
2
votes
0
answers
44
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How are frequency combs obeying the energy conservation?
The operational principle of frequency combs is that you generate very short pulses (in time domain), and that in the frequency domain (due to Fourier's transform) the spectrum of such pulses is a ...
- 3,034
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votes
1
answer
89
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How to check laser beam polarization
Just like in my question. How to check laser beam polarization? What's the easiest experiment to do that will help me understend what type of polarization is present in my laser beam?
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70
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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 ...
- 1
1
vote
1
answer
128
views
Temporal vs Spatial Contrast in Speckle Contrast Imaging
I have been reading about Speckle Contrast Imaging recently. Its quite an interesting topic given that it should be possible with relatively inexpensive equipment. The basic premise from what I ...
- 297
1
vote
0
answers
30
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Can laser diode characteristics comparison be based on laser of one length?
As we know, e.g. from this website, to know the laser Transparency Threshold Current and Internal Quantum Efficiency, we need the LI curves from lasers of various widths.
However sometimes it is ...
- 3,034
1
vote
1
answer
794
views
What is the difference between this "spectral width" and the laser linewidth (FWHM)?
I am currently looking at the 1550nm fibre-coupled DFB laser diodes on Alibaba for use in interferometry experiments. These are commonly used in optical communications applications, but it seems to me ...
- 889
1
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0
answers
47
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Why do two-beam interferometers have a relatively broad "fringe width" compared to single-beam interferometers?
I recently overheard someone discussing the basics of interferometry setups. They said that two-beam interferometers have a relatively broad "fringe width" compared to single-beam ...
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2
votes
0
answers
162
views
Is spatial coherence more important for interferometry, or is temporal coherence more important for interferometry?
I am currently going back through my textbook Laser Systems Engineering by Keith Kasunic. Chapter 1.2 Laser Engineering says the following:
One of the primary goals of laser engineering is to meet ...
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1
vote
1
answer
82
views
What aspects of the design of a beamsplitter cube determine wavefront error/distortion?
I was recently looking into having some custom beamsplitter cubes made. I require good wavefront quality, so I wanted to ensure that this was a primary consideration of the design (see how Thorlabs ...
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1
vote
1
answer
65
views
Is it possible for an atom to contain multiple electrons in the same excited state?
This question mostly stems from my quite rudimentary knowledge of laser physics. As far as I understand it, all the 3,4,..-level-systems regard the electrons being in more or less excited states. ...
- 15
1
vote
1
answer
58
views
What is the wavefront quality of VCSELs? How does the wavefront quality of VCSELs compare to Fabry-Perot laser diodes and DPSS lasers?
I am currently looking at this VCSEL. According to the datasheet, it has a narrow spectral linewidth and emits a Gaussian beam, which are both properties that I find interesting. But I'm also ...
- 889
1
vote
0
answers
57
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What does it mean by "the apparent linewidth is limited by the measurement resolution, which is $7.5 \ \text{GHz} \ (0.25 \ \text{cm$^{-1}$})$"?
The datasheet for this VCSEL has the following graph:
What does it mean by "the apparent linewidth is limited by the measurement resolution, which is $7.5 \ \text{GHz} \ (0.25 \ \text{cm$^{-1}$})...
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3
votes
1
answer
434
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Comparison of beam divergence between laser diode and DPSS lasers
I'm currently comparing a pulsed laser diode and a pulsed DPSS laser. For the DPSS laser, the beam divergence is listed as "beam divergence (80% of total energy): $<4 \text{mr}$". The ...
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