Sketch of the configuration of the setups. (a) For the detuning effect studies: 1, laser; 2, chopper; 3, polarizer; 4, quartz crystal wafer; 5, QCM window cell. (b) A home-built SPR spectrometer whose photodiode detector is replaced by a silica-coated quartz crystal wafer with frequency monitoring. M.S. stands for motor steering; (c) A combination setup of grating-coupled SPR spectrometer and QCM. P.D. stands for photodiode detector.
Reversible switching of the fundamental oscillation frequency (solid line) of an -cut quartz crystal wafer at a constant temperature (dotted line) by the on/off switching of a laser beam of , , chopper frequency , incident on the front gold electrode of the quartz crystal wafer.
(a) Frequency response of an -cut quartz crystal wafer in air at upon normal incidence of a red helium-neon laser with different average intensities onto the front gold electrode of the crystal wafer. (b) SPR curve recorded using a quartz crystal wafer with a silica coated surface as the detector. The average intensity of the red helium-neon laser beam was and the pulse frequency .
Frequency response of an -cut quartz crystal wafer in air at upon the on/off switching of a red helium-neon laser beam with - (solid line) or - (scatters) polarization. The average laser beam intensity is and is chopped with pulse frequency of .
Frequency response of a gold-coated sensor crystal wafer upon irradiation with laser beams of different wavelengths at , .
Frequency response of an -cut quartz crystal wafer in air at upon detuning of the quartz frequency upon changing the frequency by which the light of a red helium-neon laser with is chopped. The chopper frequency is changed while the laser beam is blocked.
Frequency responses (dashed line) of a gold-coated sensor crystal upon change of temperature (solid line).
Frequency response of a gold-coated sensor quartz crystal wafer upon irradiation by a xenon lamp in the presence of air, ethanol, and water, respectively.
Frequency response (dotted lines) of a grating-structured (grating constant ) -cut quartz crystal wafer in water at upon angular scans (solid lines) from to using a red helium-neon laser beam with an average intensity of and is chopped with pulse frequency of . The polarizations of the beam are (a) TE (-pol) and (b) TM (-pol). In the incident angle range from to , the laser beam is blocked by the photodiode detector and the actual reflectivity is not measured.
Calculated optical parameters of a gold layer at for different wavelengths. The reflectance is calculated for normal incidence using the Fresnel model, and the thickness of the gold layer is 120 nm.
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