| Summary: | 碩士 === 國立臺灣大學 === 物理研究所 === 100 === In bio-materials, confocal fluorescence(CF) microscopy reaching penetration depth over 100μm is difficult because of turbidity of soft-material and scattering of complex structure. Based on scattering theory, the longer wavelength, the lower scattering effect. We can increase penetration depth by using larger wavelength with less scattering. Because of double frequency of excitation, two-photon fluorescence (2PF) microscopy and second harmonic generation (SHG) microscopy can observe more deeper than 500 μm, even to reach 1 mm . Therefore, a bio-imaging system combined with an infrared (IR) source is required. However, only special wavelength can excite to fluorescence of bio-materials or stains, IR sources are not commonly applied to fluorescence microscopy. On the other hand, for imaging, SHG microscopy is free on excitation wavelength selection as far away resonance frequency. In our experiment, we expect to generate multi-frequencies laser source in IR. By optical parametric generation (OPG), we easily generate IR laser source on periodically poled lithium niobate (PPLN), which is tunable frequency, high intensity and ultrafast pulse duration. Commonly, in our system, the power of the tunable source is at least 60 mW from 1315 nm to 1650 nm, and the highest is over 1 W. The tunable IR source properly apply to SHG microscopy. Combined OPG with SHG microscopy, we can achieve spectral imaging.
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