Asynchronous Time-Resolved Fourier Transform Infrared Spectroscopy

Abstract

A novel asynchronous time-resolved FT-IR spectrophotometer based on a conventional continuous-scan interferometer has been developed. In contrast to the existing methods, this method does not require the synchronization between the signal for time resolving and that for the sampling of the A/D converter. The signal-processing assembly for time-resolved measurements consists of a pulse generator, a pulse delay circuit, a gate circuit, and a low-pass filter. This assembly can be attached to any conventional FT-IR spectrophotometer. By this method, time-resolved spectra without any spectral distortion or artifacts can be obtained for repetitive fast phenomena. As an application of this method, time-resolved FT-IR measurements have been carried out for the reorientation process in a ferroelectric liquid crystal induced by the reversal of external electric field, and a time resolution of 0.5 μs or less has been achieved. The present system is best suited for observing repetitive transient phenomena with lifetimes in the range from approximately 1 μs to 1 ms.

Keywords

Fourier transform infrared spectroscopy Instrumentation Liquid crystal Reorientation Time-resolved spectroscopy

Get full access to this article

View all access options for this article.

References

Murphy

R. E.

Cook

F. H.

and Sakai

, J. Opt. Soc. Am. 65, 600 (1975).

Sakai

and Murphy

R. E

, Appl. Opt. 17, 1342 (1978).

Mantz

A. W.

, Appl. Spectrosc. 30, 459 (1976).

Mantz

A. W.

, Appl. Opt. 17, 1347 (1978).

Durana

J. F.

and Mantz

A. W

, “Laboratory Studies of Reacting and Transient System,” in Fourier Transform Infrared Spectroscopy, Ferraro

J. R.

and Basile

L. J

, Eds. (Academic Press, New York, 1979), Vol. 2, Chap. 1.

Griffiths

P. R.

and De Haseth

J. A

, Fourier Transform Infrared Spectrometry (John Wiley and Sons, New York, 1986), Chap. 12.

Sloan

J. J.

and Kruus

E. J

, “Time-Resolved Fourier Transform Spectroscopy,” in Advances in Spectroscopy, Clark

R. J. H.

and Hester

R. E

, Eds. (John Wiley and Sons, Chichester, 1989), Vol. 18, Chap. 5.

Uhmann

Becker

Taran

and Siebert

, Appl. Spectrosc. 45, 390 (1991).

Manning

C. J.

Palmer

R. A.

and Chao

J. L

, Rev. Sci. Instrum. 62, 1219 (1991).

10.

Crocombe

R. A.

and Compton

S. V

, FTS/IR Notes of Bio-Rad Digilab Division, No. 82 (1991).

11.

Palmer

R. A.

Manning

C. J.

Chao

J. L.

Noda

Dowrey

A. E.

and Marcott

, Appl. Spectrosc. 45, 12 (1991).

12.

Toriumi

Sugisawa

and Watanabe

, Jpn. J. Appl. Phys. 27, L935 (1988).

13.

Bracewell

R. N.

, The Fourier Transform and Its Applications (McGraw-Hill, New York, 1965), 2nd ed., Chap. 5, p. 77.

14.

Vanasse

G. A.

and Sakai

, “Fourier Spectroscopy,” in Progress in Optics, Wolf

Ed. (North-Holland, Amsterdam, 1967), Vol. 6, Chap. 7, p. 275.