TY - JOUR
T1 - Three-photon-induced fluorescence of diphenylhexatriene in solvents and lipid bilayers 3
AU - Malak, Henryk
AU - Gryczynski, Ignacy
AU - Dattelbaum, Jonathan D.
AU - Lakowicz, Joseph R.
PY - 1997/1/1
Y1 - 1997/1/1
N2 - We observed the emission of 1,6-diphenyl-1,3,5-hexatriene (DPH) when excited with the fundamental output of a fs Ti:sapphire laser at 860 nm. The emission spectra of DPH were identical to that observed for one-photon excitation at 287 nm. The dependence of the DPH emission intensity on laser power was cubic, indicating three-photon excitation of DPH at 860 nm. At a shorter wavelength of 810 nm, the dependence on laser power was quadratic, indicating a two-photon process. At an intermediate wavelength of 830 nm the mode of excitation was a mixture of two- and three-photon excitation. At 830 nm the anisotropy is no longer a molecular parameter, and the mode of excitation and anisotropy of DPH depends on laser power. Frequency-domain anisotropy decays of DPH in triacetin revealed the same rotational correlation times for two- and three-photon excitation. However, the time 0 anisotropy of DPH was larger for three-photon excitation than for two-photon excitation. Steady-state anisotropy data for DPH-labeled membranes revealed the same transition temperature for one- and three-photon excitation. These anisotropy data indicate that membrane heating was not significant with three-photon excitation and that three-photon excitation may thus be of practical usefulness in fluorescence spectroscopy and microscopy of membranes.
AB - We observed the emission of 1,6-diphenyl-1,3,5-hexatriene (DPH) when excited with the fundamental output of a fs Ti:sapphire laser at 860 nm. The emission spectra of DPH were identical to that observed for one-photon excitation at 287 nm. The dependence of the DPH emission intensity on laser power was cubic, indicating three-photon excitation of DPH at 860 nm. At a shorter wavelength of 810 nm, the dependence on laser power was quadratic, indicating a two-photon process. At an intermediate wavelength of 830 nm the mode of excitation was a mixture of two- and three-photon excitation. At 830 nm the anisotropy is no longer a molecular parameter, and the mode of excitation and anisotropy of DPH depends on laser power. Frequency-domain anisotropy decays of DPH in triacetin revealed the same rotational correlation times for two- and three-photon excitation. However, the time 0 anisotropy of DPH was larger for three-photon excitation than for two-photon excitation. Steady-state anisotropy data for DPH-labeled membranes revealed the same transition temperature for one- and three-photon excitation. These anisotropy data indicate that membrane heating was not significant with three-photon excitation and that three-photon excitation may thus be of practical usefulness in fluorescence spectroscopy and microscopy of membranes.
KW - Anisotropy decays
KW - Diphenylhexatriene
KW - Fluorescence intensity decays
KW - Membranes
KW - Multiphoton excitation
KW - Three-photon excitation
KW - Two-photon excitation
UR - http://www.scopus.com/inward/record.url?scp=0002522901&partnerID=8YFLogxK
U2 - 10.1007/BF02760500
DO - 10.1007/BF02760500
M3 - Article
AN - SCOPUS:0002522901
SN - 1053-0509
VL - 7
SP - 99
EP - 106
JO - Journal of Fluorescence
JF - Journal of Fluorescence
IS - 2
ER -