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Advances in Grating‐Based Photoacoustic Spectroscopy for the Study of Protein Dynamics
Author(s) -
Dadusc Gami,
Goodno Gregory D.,
Chiu HuiLing,
Ogilvie Jennifer,
Miller R.J. Dwayne
Publication year - 1998
Publication title -
israel journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.908
H-Index - 54
eISSN - 1869-5868
pISSN - 0021-2148
DOI - 10.1002/ijch.199800021
Subject(s) - grating , chemistry , picosecond , optics , spectroscopy , photoacoustic spectroscopy , signal (programming language) , phase (matter) , beam (structure) , laser , physics , organic chemistry , quantum mechanics , computer science , programming language
Recent advances in transient grating spectroscopy are described in relation to extracting photoacoustic parameters. The time resolution for measurement of dynamically driven acoustics has been extended to the picosecond level. This improvement was achieved by adopting counter‐propagating beam geometries and resolving the acoustic phase shift in analogy to phase modulation spectroscopy. At the other extreme, the dynamic range of this technique has been extended to milliseconds in order to follow dynamical processes central to biological functions. In addition, diffractive optics were used for generating the necessary excitation and probe beam geometries. A novel optical setup was developed which permits both the rapid exploration of fringe spacing dependencies in separating thermal from nonthermal contributions to the observed signal as well as heterodyne detection without active feedback. The latter capability significantly increases the signal‐to‐noise ratio and permits separation of the real and imaginary components from the nonlinear four‐wave‐mixing signal. Applications of these new methods are demonstrated by following the functionally relevant structural relaxation processes of heme proteins over 10 decades in time.