- #1
JGarry
'Morning all,
I wish to use a 760nm laser to measure the concentration of molecular oxygen in a gas. I've a laser (multi-mode, not TDLAS:QLD-760-10S), a photodiode (Si), and I've built an oven to hold the laser diode at a constant temperature to avoid mode-hopping.
Is it really as 'simple' as modulating the diode current at some frequency, amplifying the PD output, and then deconvolving the sampled output with the modulating frequency?
At RTP, with 20% O2, I've a gut feeling that 1m path length ought to give something like 0.1% absorption of the total laser power.
Any comments about technique?
I wish to use a 760nm laser to measure the concentration of molecular oxygen in a gas. I've a laser (multi-mode, not TDLAS:QLD-760-10S), a photodiode (Si), and I've built an oven to hold the laser diode at a constant temperature to avoid mode-hopping.
Is it really as 'simple' as modulating the diode current at some frequency, amplifying the PD output, and then deconvolving the sampled output with the modulating frequency?
At RTP, with 20% O2, I've a gut feeling that 1m path length ought to give something like 0.1% absorption of the total laser power.
Any comments about technique?