Phosphorous doped diamond like carbon (DLC) films deposited on a p-type silcon (or quartz) substrate by plasma assisted laser ablation method for fabrication of photovoltaic solar cells. Frozen benzene and spread trimethyl-phosphate target or phosphorous powder mixing pressed graphite carbon target was ablated by free electron laser (resonance absorption wave length of benzene : 1680 nm) or ArF excimer laser (wave length : 193 nm). In order to etch the oxygen in plume of benzene and trimethyl-phsophate, inductively coupled hydrogen plasma by radio frequency (frequency :13.6 MHz) discharge flow between target and substrate. Effect of resonance excitation of benzene target by turning free electron laser or directly photon energy excitation by ArF excimer laser were discussed for widely band gap, larger short-circuit current density and open-circuit voltage at solar cell.
It is important to detect the metal fatigue in the steel. There are several known methods of detecting metal fatigue. However, there is a problem in which it is not the non- destruction and large equipment. We are investigating the method of metal fatigue by the laser induced thermal vibration. When the target absorbs a laser beam, the temperature gradient occurs in the surface and the back of the target. The steel is bent by this temperature gradient. When the intensity of laser is modulated, the target vibrates by the repetition of the bending. This method detects the metal fatigue from the variations of the amplitude vibration by material degradation, which is generated by the metal fatigue. It is non-destructive evaluation method and simple equipment. We succeeded in the detection of the metal fatigue by this method from the sample, which beforehand added the fatigue. In this paper, we compared the detection result with addition way of the fatigue. Then, effectiveness and features of this method were confirmed.
Optical lens of micrometer order diameter for coupling between optical fiber and laser diode were formed by argon ion laser polymerization method at visible light cured resin. Test resin materials consisted of triethylene glycol dimethacrylate for main resin, camphorquinon for photo initiator of visible light area, hydroquinon for inhibitor, and N,N-dimethylmethacrylate for reducing agent. In order to obtain the micro lens of short focal length and small spherical aberration, the use of this technique makes it possible to simultaneously form the polymerized aria on glass plate at the argon ion laser beam irradiation zone. The polmerized aria made a high quality micro lens without using molding pattern. We have verified our claims with visual inspection, ray trajectory calculations for measurement of side long spherical aberration (transverse aberration), Fourier transform infrared spectroscopy for degree of conversion analysis of polymerized resin area, and Duc de Chaulnes method for measurement of lens shape. The lens has a diameter of 300micrometers or more, a focal length of 500micrometers or more with an NA of 0.5, and transverse aberration plot of about 100% of the within the limits of +/- 25micrometers . This method can be applied for producing circular, non-circular, linear, and array micro lenses by scanning or patterning of argon ion laser beam.
We propose a novel system to produce the short pulse using a halved confocal of the unstable concave-convex resonator on radio frequency discharge excitation slab type carbon dioxide laser. This method is provided a full reflection concave mirror to have a function of variable curvature which can control using a piezo electric device (PZT). Generally, the slab type laser is directly modulated by applying pulse voltage for pulsation of laser. There is a large capacity and fluctuation of plasma at the transition of pulsation. Consequently, the pulse width is longer than 1.0 micro second and repetitive frequency is less than 10 kilo Hertz. On the other hand, the pulse oscillation by our proposed method has the short pulse width which is 300 nano second and maximum repetitive frequency is about 100 kilo Hertz. We can choose the pulse oscillation or the continuous wave (CW) oscillation at the each condition on same resonator. The peak power at the pulse oscillation is about 12 times as high as that at the CW oscillation.
We have developed a technique for a higher degree of polymerization at the deep area of dental restorative resins by argon ion laser irradiation. We provide an analysis of the resin materials by Raman spectroscopy and Fourier transform infrared spectroscopy.
We have developed a method of producing micro-lenses on soda-lime glass plates by combining the techniques of laser annealing and an ion-exchange method, henceforth referred to as the `laser ion-exchange method.' The use of this technique makes it possible to simultaneously increase the refractive index on both sides of a glass plate at the laser beam irradiation zone. The increase in the refractive index on both sides complement each other to make a high quality micro-lens with a very short focal length. This method can be applied for producing circular, noncircular, linear, and array micro-lenses.
We have developed a technique of depositing a synthetic diamond-like carbon film on glass substrates in atmosphere at ambient temperature. By placing a glass substrate within the plume created by irradiating a carbon target with a Nd-YAG laser, we are able to deposit a diamond-like carbon film on the surface of the substrate. Using a highly purified graphite carbon target insures that only carbon ions are ejected and present in the plume. We will provide an analysis of the films by both vertical and diagonal irradiation (see Figs.1(A) and 1(B)), by Raman spectroscopy and electron probe micro analysis.