A subsidiary electrode was introduced between the extractor and anode in our newly developed source lens design of a micro electron column to improve the probe beam characteristics. At the same field enhancement factor of 3.95, the probe beam current showed a drastic increase compared to that of the conventional source lens structure. The design parameters of the newly developed source lens structure and the equipotential line distribution are presented with simulation results.
We suggested a laser inspection method of interference and diffraction for checking if any defect in a RF device such
as SAW filter and delay line. The real time optical metrology that we proposed can provide a visualized positional
vibration, unlike the electric method that is capable of checking only product defect. It can substitute a conventional test
method of electrical with finding out where the vibration is weak or disturbed by other service frequency module. The
measuring limits with a single-mode laser source are also given and what measuring conditions should be satisfied for
detecting a fine displacement or vibration like propagation of a surface acoustic wave in RF device. The interference and
diffraction due to RF signal are analyzed by an optical interpretation. In this paper, a single mode laser and a 105MHz-center-
frequency repeater filter were employed for experiments and theoretical analysis. The optical metrology providing
visual energy distribution and real time inspection for surface acoustic wave is proposed for development of high quality
multi-service and multi-frequency RF module.
The thermally induced birefringence was successfully compensated by placing a quarter-wave plate into a plane parallel Nd:YAG laser resonator of 130 W output power in multi-mode. The optimal conversion efficiency was 38.3% and the slope efficiency was 58.2% with output coupler of 80% reflectance, and the beam quality factor of M2 was 26.7. For higher modes elimination, an aperture of 1.5 mm in diameter was inserted into resonator, and M2 was decreased to 1.8. However, the insertion of quarter-wave plate made an additional improvement to 1.15 of M2 value by alternating their radial and tangential polarization directions every bouncing feedback. We report the experimental results with theoretical analysis for high power solid-state laser fabrication with better beam quality.
We report the optical and lasing characteristics of neodymium doped lanthanum scandium borate. Nd:LSB microchip laser devices were fabricated from the conventional Czochralski pulling method with different doping concentration. The space group of Nd:LSB was studied with their optical characteristics. In the lasing experiment the hot-band pumping, 4F3/2, showed an improvement of slope efficiency and threshold comparing to the conventional pumping to 4F5/2 absorption band.
The single crystals of neodymium doped lanthanum scandium borate were grown for the microchip laser fabrication. The crystal structure and parameters were analyzed to define the crystal phase and characteristics. The optical properties, such as fluorescent lifetime, refractive indices, absorption and emission spectra with doping concentration, were investigated and compared to the other neodymium doped single crystals in laser application. The fundamental lasing experiment with 808 nm, consistent with commercial diode laser wavelength, was done with Ti:sapphire laser. And we showed that the direct pumping to the level of 4F3/2 make an improvement in slope efficiency and threshold when it is compared to the result of conventional pumping to the level of 4F5/2 absorption band. The direct pumping played a role for reduction of dissipative heat generation in microchip laser crystal, because its quantum efficiency is higher than the conventional pumping to the level of 4F5/2.