研究目的
Investigating the photo-induced second harmonic generation in centrosymmetric polystyrene microspheres and its reversible behavior under laser-pulse irradiation.
研究成果
The study found photo-induced, reversible SHG in centrosymmetric polystyrene microspheres. The SHG signal gradually increases with stationary laser-pulse irradiation and disappears after stopping the irradiation, reappearing with similar temporal behavior upon further irradiation. This finding might be applicable to labeling a particular intra-cellular or intra-tissue bio-polymer by SHG where some types of bio-polymers in cells and tissues depict similar properties.
研究不足
The study does not provide a detailed explanation of the origin of the SHG signal in centrosymmetric polystyrene microspheres. The changes in CARS spectra were not significant, possibly because the photo-induced domain was not large enough to be detected by CARS under the present experimental conditions.
1：Experimental Design and Method Selection:
The study used a coherent nonlinear optical microscopic system with a Q-switched microchip Nd:YAG laser as a master laser source. Part of the output was used for ω1 laser (pump laser), and the remaining part was introduced into a photonic crystal fiber to generate supercontinuum radiation used as an ω2 laser. The SHG, THG, and CARS signals were detected using spectrometers equipped with CCD cameras.
2：Sample Selection and Data Sources:
Polystyrene beads (diameter 10 μm) were purchased from Polysciences, Inc. The original aqueous suspension of the beads was diluted more than 10-times, and approximately 50 μl of the suspension was sandwiched between a cover glass and a slide glass.
3：List of Experimental Equipment and Materials:
Q-switched microchip Nd:YAG laser, photonic crystal fiber, modified inverted microscope (ECLIPSE Ti, Nikon), piezoelectric stage (Nano-LP200, Mad City Lab), water-immersion objective lens (CFI Plan Apo 60× NA 1.27, Nikon), spectrometers (SpectraPro300i Princeton Instruments, LS785, Princeton Instruments), CCD cameras (PIXIS 100B, Princeton Instruments; BLAZE 100HR, Princeton Instruments), portable Raman spectrometer (Smart RamanXI, CloudMinds).
4：27, Nikon), spectrometers (SpectraPro300i Princeton Instruments, LS785, Princeton Instruments), CCD cameras (PIXIS 100B, Princeton Instruments; BLAZE 100HR, Princeton Instruments), portable Raman spectrometer (Smart RamanXI, CloudMinds). Experimental Procedures and Operational Workflow:
4. Experimental Procedures and Operational Workflow: The laser pulses were tightly focused using a water-immersion objective lens. The SHG, THG, and CARS signals were collected by the second objective lens and detected by spectrometers equipped with CCD cameras. The sample was placed on a piezoelectric stage for position selection.
5：Data Analysis Methods:
The SHG intensity was obtained by fitting the spectral profile of the SHG signal using a Gaussian function and mapping out its amplitude. The dynamic behaviors of the SHG, THG, and CARS signals were analyzed using time-resolved spectroscopy.
独家科研数据包，助您复现前沿成果，加速创新突破
获取完整内容-
Piezoelectric stage
Nano-LP200
Mad City Lab
For position selection of the sample.
-
Q-switched microchip Nd:YAG laser
Master laser source for generating ω1 and ω2 laser beams.
-
Photonic crystal fiber
Generating supercontinuum radiation used as an ω2 laser.
-
Modified inverted microscope
ECLIPSE Ti
Nikon
For focusing laser pulses and collecting signals.
-
Water-immersion objective lens
CFI Plan Apo 60× NA 1.27
Nikon
For tightly focusing laser pulses.
-
Spectrometer
SpectraPro300i
Princeton Instruments
For detecting SHG, THG, and TSFG signals.
-
CCD camera
PIXIS 100B
Princeton Instruments
For detecting SHG, THG, and TSFG signals.
-
Spectrometer
LS785
Princeton Instruments
For detecting CARS signals.
-
CCD camera
BLAZE 100HR
Princeton Instruments
For detecting CARS signals.
-
Portable Raman spectrometer
Smart RamanXI
CloudMinds
For spontaneous Raman spectroscopy.
-
登录查看剩余8件设备及参数对照表
查看全部
