RF mosfets and laser generation

[dru]

I was reading the data sheet for an RF MOSFET today and was very surprised to see laser generation as the first listed application. To my knowledge the longest wavelength semiconductor laser is 450um currently, so how could a MOSFET that switches at a max of 250mhz be useful in laser generation? A quick calculation puts the shortest producible wavelength from this fet at about 1.2m. https://www.nxp.com/docs/en/data-sheet/MRF300AN.pdf

[Da_Stier]

Hi dru,

you wouldn't use them to directly generate laser light. You would build an RF source with high CW power output (normally in the 27MHz ISM band).
This generator is then used to ionize some gas to generate a laser beam.
I think it is called something along the lines of "RF doped laser" or "RF doped plasma".

I'm not really an expert in any way in this field, I only reused some of the RF equipment from it.



Greetings,
Michael

[dru]

Hi dru,

you wouldn't use them to directly generate laser light. You would build an RF source with high CW power output (normally in the 27MHz ISM band).
This generator is then used to ionize some gas to generate a laser beam.
I think it is called something along the lines of "RF doped laser" or "RF doped plasma".

I'm not really an expert in any way in this field, I only reused some of the RF equipment from it.



Greetings,
Michael

Hi Michael, thanks for the response! That makes sense, I had a feeling it had something to do with gas discharge lasers. I remember when I was researching helium-neon lasers that the power supply was usually switching at much lower frequencies, around 15khz, so that's why I was confused. I did some digging and I found in some he-ne lasers used for research they excite the gas with rf generators, so I'm guessing that's the type of application of this mosfet.