Spectroscopy before tunable lasers?

[houlahound]

how was it done?

 

[DrClaude]

I guess you mean absorption spectroscopy: wide-spectrum light source, a grating, and a narrow slit.

 

[houlahound]

sounds like a lot of setting up.

 

[DrClaude]

sounds like a lot of setting up.

More than a tunable laser?

 

[DrClaude]

See http://antiquesci.50webs.com/PE337/PE337-1.htm

 

[houlahound]

Edit - viewed link, nice instrument.

 

[DrClaude]

I would like to see the power spectrum and bandwidth of a line from the source. so a frequency sweep means you change the angle of the diffraction grating - ouch.

I don't see the difficulty in that. In the old-old days, it was done manually (grating on a pivot), later using a motor.

 

[houlahound]

I guess if I got this right due to the physical set up a particular line you select is locked there indefinitely and you just know it's that wavelength forever.

the only time I did real spectroscopy there was continual drift and I had to fix the wavelength with a beam splitter and compare to another sample of with known line. there was always mode hopping issues but that did not bother what I was doing.

I suspect tunable lasers are prolly all automated now to stay on a line. the bandwidth was very narrow, would like to know what the bandwidth is for the antique instrument in the link.