All Questions
Tagged with photonics laser-cavity
13
questions
0
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0
answers
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,...
2
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0
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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 ...
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1
vote
1
answer
794
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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 ...
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2
votes
2
answers
668
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Explanation of 'modal gain' (especially in the context of laser diodes)
I have seen the phrase 'modal gain' used in the context of photonics. Researching this phrase, I found this resource, which explains it as follows:
Modal Gain: which is the material gain adjusted to ...
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14
votes
3
answers
854
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What happens to the non-axial photons of a laser cavity?
When a laser cavity is pumped, the axial photons are reflected back and forth by the cavity mirrors and so contribute to stimulated emission, but the non-axial photons do not have this opportunity. ...
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0
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1
answer
105
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There may be phase variations $\ge \lambda/4$ across the diameter of each mirror in any laser cavity?
I am currently studying the textbook Laser Systems Engineering by Keith Kasunic. Chapter 1.2.2 Spatial coherence says the following:
The concepts of spatial coherence and beam quality arise because ...
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1
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0
answers
226
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Which of those two is better way of avoiding mode hopping in laser?
I'm supposed to design a laser cavity that would avoid mode hopping.
I have two projects in mind, and I did some simulations. The result for relative intensity of modes (no gain spectrum in account, ...
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1
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1
answer
181
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Why can no commercial laser products achieve a frequency stability of $< 1 \ \text{Hz}$?
I am currently studying the textbook Laser Systems Engineering by Keith Kasunic. Chapter 1.2.1 Temporal coherence says the following:
Even a frequency-stabilized SLM laser has a linewidth – an ...
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5
votes
1
answer
580
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Homogeneous gain saturation and single-longitudinal-mode lasing
I am currently studying Laser Systems Engineering by Keith Kasunic. Chapter 1.2.1 Temporal Coherence says the following:
Whether or not multiple axial modes will lase depends, in part, on the cavity-...
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0
votes
1
answer
133
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If most types of practical lasers produce a large number of half-wavelengths, then how are they practical for use at all?
I am currently studying Laser Systems Engineering by Keith Kasunic. Chapter 1.2.1 Temporal Coherence says the following:
Axial (or longitudinal) modes are determined by the geometrical fit (or ...
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2
votes
1
answer
619
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Half-wavelengths of the electric field fit in the cavity length $L$: $m \frac{\lambda}{2n} = L$
I am currently studying Laser Systems Engineering by Keith Kasunic. Chapter 1.2.1 Temporal Coherence says the following:
Axial (or longitudinal) modes are determined by the geometrical fit (or ...
- 889
1
vote
0
answers
34
views
What is the physical meaning behind negative slope of laser characteristics?
Sometimes I measure LIV curves of many semiconductor lasers with the same material and width and different cavity length.
There should be positive slope and intercept of Threshold current vs inverse ...
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0
votes
2
answers
148
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In the end, how do I make a semiconductor laser with specific wavelength?
I know that laser wavelength depends on four important properties:
Bandgap of its material
Gain spectrum
Length of cavity
Size of a quantum well, if we talk about the quantum well laser
But it's a ...
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