Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
(a) 2f-WMS Photoacoustic signal for modulation depths from 0.048 nm to 0.333 nm of the same NH3 absorption lines. (b) Peak to peak 2f-WMS photoacoustic signal as a function of the modulation depth. All measurements were performed with a 5000 ppmv NH3 in N2 mixture, atmospheric pressure, room temperature and a 300 ms lock-in amplifier time constant.
