Spectroscopic method with double modulation

Details Spectroscopic method with double modulation Spectroscopic method with double modulation

1995-05-23

1997-06-17

Font, Frank G.

Optics: measuring and testing

For light transmission or absorption

Of fluent material

356432, G01N 2100

Patent

active

056402457

ABSTRACT:
To improve the signal-to-noise ratio in trace analysis in gases or plasmas (3) by absorption spectroscopy the wavelength of the analyzing beam of a semiconductor laser (1) is modulated by a frequency f.sub.1 and the absorption length or population density of absorbing particles of the plasma is modulated by a frequency f.sub.2. For the measurement a lock-in amplifier (5) coupled to a photodiode (4) is tuned to the sum or difference frequency of the frequencies f.sub.1 and f.sub.2 or whole-number multiples thereof.

REFERENCES:
patent: 4934816 (1990-06-01), Silver et al.
patent: 5267019 (1993-11-01), Whittaker et al.
Journal of the Optical Society of America vol. 6, No. 5, May 1989 pp. 871-876; "High-sensitivity frequency-modulation spectroscopy with a GaAlAs diode laser"; Liang-Guo Wang, et al.
Journal of Physics D: Applied Physic's 26 (1993) 14 Feb., No. 2, Bristol, G.B. pp. 199-202; "Measurement of the CF3 radical using infrared diode laser absorption spectroscopy"; Kouji Maruyama, et al.
Applied Spectroscopy vol. 47, No. 3, 1993 Mar.; "Direct determination of trace elements in graphite matrices using modulated glow discharge atomic absorption spectrometry"; pp. 300-304;Ghangkang Pan, et al.
Analytical Chemistry, vol. 61, No. 21, Nov. 1, 1989 pp. 1217-1223; "Finding a single molecule in a haystack Optical detection and spectroscopy of single absorbers in solids"; W.E. Moerner, et al.

Affiliated with

Also associated with

Rating

Spectroscopic method with double modulation does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Spectroscopic method with double modulation, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Spectroscopic method with double modulation will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2161880