| Electronics > RF, Microwave, Ham Radio |
| Wave interference - If I shine 2 lasers on a spot,will there be actual blinking? |
| (1/3) > >> |
| daqq:
Hi guys, Assuming I have 2 lasers, their spectral peaks some small frequency (say, 2Hz?) apart from one another, and I shine these two lasers onto the same area. Would there be actual visible blinking on the area? Thanks, David |
| nfmax:
Yes. Though good luck finding visible-light lasers only 2Hz apart from each other (at least for a time period of more than a few milliseconds) [EDIT] I forgot to say that you will only see blinking if the two lasers share the same polarization (or have at least some part of their output identically polarised) |
| m98:
Found some interesting topic about that: https://www.researchgate.net/post/The_interference_between_two_different_lasers_at_the_same_wavelength |
| krivx:
--- Quote from: nfmax on January 20, 2016, 10:30:38 am ---Yes. Though good luck finding visible-light lasers only 2Hz apart from each other (at least for a time period of more than a few milliseconds) [EDIT] I forgot to say that you will only see blinking if the two lasers share the same polarization (or have at least some part of their output identically polarised) --- End quote --- Also requires that the laser spots have little spatial variation as well temporal. To put it in context, a 2Hz variation is about 1 part per 10^14 |
| tesla500:
I recently did a teardown of an HP laser head that did something similar to this. A special laser tube produces two wavelengths simultaneously, separated by about 2MHz. The "blinking" is easily picked up with a photo diode. This is used for an interferometer for measuring distances, and can detect movements in the nanometer range. |
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