Thermal-Lens-Induced Anomalous Solvent's effect on Fluorescence Produced by Two-Photon Continuous-Wave Laser Excitation.
نویسندگان
چکیده
Measurements of two-photon-excited fluorescence (TPF) of fluorescein and Rhodamine 6G in various solvents were performed with a continuous-wave (cw) laser for excitation and an acousto-optic tunable filter for spectral dispersion. Interestingly, the cw laser excitation produced an unwanted thermal-lens effect when the measurements were performed in solvents that absorb the excitation laser light (e.g., alcohols and water, because these solvents absorb the 780-nm excitation light through the overtone and combination transitions of the O-H group). The defocusing effect of the thermal lens leads to a decrease in the TPF signal. Because the strength of the thermal lens depends on the thermo-optical properties (dn/dT and thermal conductivity) of the solvent, its interference makes the effect of solvents on the TPF much different from those on one-photon-excited fluorescence. However, the thermal-lens interference will not limit the application of this cw laser excited TPF technique because, even when measurements were performed in solvents that absorb cw excitation laser light, the thermal-lens interference was observed only in solvents such as nonpolar organic solvents that have relatively better thermo-optical properties. Interference was not observed in water, which is the most widely used solvent for the TPF technique (because water has poor thermo-optical properties).
منابع مشابه
Two-photon excitation induced fluorescence of a trifluorophore-labeled DNA.
Two-photon excitation of a trifluorophore (6-carboxyfluorescein, N,N,N',N'-tetramethyl-6-carboxyrhodamine and cyanine-5 monofunctional dye) labeled DNA, which has a scaffold of 26 nucleotides, was achieved using focused laser light of a Q-switched Nd-YAG laser (1064 nm). The observed fluorescence signature (emission ratio from the three fluorophores) of the labeled DNA after two-photon excitati...
متن کاملUsing two-photon standing waves and patterned photobleaching to measure diffusion from nanometers to microns in biological systems
A method of measuring molecular diffusion rates in microscopic sample volumes is described. This method utilizes the standing wave interference created by colliding two counterpropagating laser beams at the focus of two opposing microscope objectives, creating a periodic light distribution in a volume on the order of 1 fl. By using a Pockels cell to vary the laser intensity with a time resoluti...
متن کاملTwo-photon excitation STED microscopy.
We report sub-diffraction resolution in two-photon excitation (TPE) fluorescence microscopy achieved by merging this technique with stimulated-emission depletion (STED). We demonstrate an easy-to-implement and promising laser combination based on a short-pulse laser source for two-photon excitation and a continuous-wave (CW) laser source for resolution enhancement. Images of fluorescent nanopar...
متن کاملSingle-molecule detection using continuous wave excitation of two-photon fluorescence.
Two-photon fluorescence (TPF) is one of the most important discoveries for biological imaging. Although a cw laser is known to excite TPF, its application in TPF imaging has been very limited due to the perceived low efficiency of excitation. Here we directly excited fluorophores with an IR cw laser used for optical trapping and achieved single-molecule fluorescence sensitivity: discrete stepwi...
متن کاملMitigating thermal mechanical damage potential during two-photon dermal imaging.
Two-photon excitation fluorescence microscopy allows in vivo high-resolution imaging of human skin structure and biochemistry with a penetration depth over 100 microm. The major damage mechanism during two-photon skin imaging is associated with the formation of cavitation at the epidermal-dermal junction, which results in thermal mechanical damage of the tissue. In this report, we verify that t...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Applied optics
دوره 39 33 شماره
صفحات -
تاریخ انتشار 2000