| Summary: | 碩士 === 淡江大學 === 物理學系 === 85 === The main purpose of the thesis is to study the basic
principles, designing and operation of a diode laser pumped
solid-state laser. A GaAlAs diode laser with a maximum output
power of 0.56 W at l=808 nm was employed to pump an a-cut Nd:
YVO4 crystal, whose high reflectivity surface and an output
mirror formed a hemiconfo? `resonator, and the end-pumping
scheme was used for mode matching between the pump beam and a
single transverse laser mode. With different output couplers
(each with different reflectively and radius of curvature), we
measure the laser output in order to maximize the output power.
Whenthe pumping power is fixed, the output power is related to
the internal losses of the cavity and the pumping condition. The
choice of using a hemiconfocal resonator for our experiment was
for easy laser alignment, high stability, and obtaining a TEM00
mode whose spot size on the laser crystal and beam divergence
are both moderate. In this case, when the cavity length gets
shorter, the beam waist becomes smaller, while the beam
divergence becomes larger. It was found that the polarization of
the Nd:YVO4 laser output is always perpendicular to the c axis
of the laser crystal, and the pump absorption efficiency is
highest when the c axis is in same direction as the polarization
of the pump beam. Spectral analyses of the pump laser and the
Nd:YVO4 laser showed that when the driving current of the pump
laser is increased, the output of both lasers tends to shift
towards longer wavelengths; also, it was found that there were
two distinct components in the Nd:YVO4 laser output whose
wavelenght separation is about 1.9{SYMBOL 197 \f "Book Antiqua"
}. In the fluorescence spectrum of Nd:YVO4, we found that in
addition to the 1064-nm signal, three intense wavelength
components appear around 878 nm, 888 nm, and 914 nm,
respectively.
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