All Questions
12
questions
5
votes
3
answers
2k
views
Can an LED be used as a receiver and as an emitter?
I have this idea but I do not know if it makes sense. The idea is to use a red transparent LED connected to an input of a microcontroller. In parallel it is also connected to an output of the same ...
- 299
0
votes
1
answer
162
views
VCSEL to project a 2D array of dots [closed]
Background
Apple iPhone Face ID uses VCSEL inside its dot projector to project infrared dots into a person face. Then an infrared camera captures the pattern to be used in a structured light algorithm ...
- 377
0
votes
1
answer
72
views
How to convert spontaneous emission into stimulated?
I have a semiconductor diode that has spontaneous emission (LED).
The question is what can I change in the fabrication of the diode to improve its performance such that the diode gains a stimulated ...
0
votes
2
answers
200
views
How optical sources having narrower spectral width gives higher data rates?
How optical sources having narrower spectral width '\$ \Delta \lambda \downarrow \$' gives higher data rates '\$ R_B \uparrow \$'?
For example: Laser having lower spectral width gives higher data ...
- 145
1
vote
1
answer
209
views
Energy delivered by a LED in Joule
Please help me with calculation
I read in the link
https://www.thorlaser.com/LLLT/calculating-LLLT-dosage.htm
A 500mW laser with a beam area of 0.25Cm2 used for 20 seconds
delivers 40 J/cm²
A 200mW ...
- 61
1
vote
1
answer
289
views
Determining LED safety compliance
I have a compliance audit that has been foisted on me from on high - as part of what an external consultancy has highlighted, I now have to prove that the indicator LEDs on a board I designed a long ...
- 4,172
10
votes
4
answers
9k
views
What's the difference between a laser diode and ordinary LED?
What are the discerning properties that distinguish them; determining their different characteristics?
In other words, I'm trying to do a compare / contrast:
What do they have in common?
How are ...
- 1,089
0
votes
2
answers
73
views
Low-cost way of shining a wide line of light, kind of like some bar code scanners do [closed]
What is a cost-effective way (say roughly $15) to shine a wide but thin beam of light, directly away from the source, so that it would project a line onto a nearby surface?
My particular beam would ...
- 103
1
vote
1
answer
1k
views
Narrowband LED performance compared to Laser for Spectroscopy
I am currently building my own Raman spectrometer and I am in the process of choosing a light source. I am deciding whether I should be using LEDs vs traditional laser modules.
These are my ...
- 111
0
votes
2
answers
412
views
What are some LED technology for one dimensional coherent light emission?
I need to emit a unidirectional infrared pattern, i.e. the emission cone should have small angle on one dimension and large angle on the other one (basically laser-like in one dimension and normal ...
- 355
6
votes
4
answers
11k
views
Driving an LED/Laser diode with a RF signal up to 20 MHz
I'm trying to design a circuit that will let me drive an LED or Diode laser with a RF signal up to ~20 MHz or so. Since the optical device will need to be biased with a DC current, a bias -t is a ...
- 1,132
0
votes
2
answers
193
views
Does solid state maser exist?
In my student years we studied the microwave quantum device, equivalent to laser, named maser. It worked on ammonia molecules, so it was not a solid state. It has phenomenal specs, as quantum device ...
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