Study on the SFG digital imaging by using nanometer polarization control

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In this research, the following results were achieved since it was concerned with the domain inversion and microfabrication technologies those became important in malting the proposed device.1)The proposal and the proof of the new domain inversion control method : A new circular form full cover electrode (FCE) method was proposed to fabricate periodic domain inversion in the LiNbO_3 (LN) crystal with a period of 2 μm or less. First of all, it was suggested that the circular electrode provided point contact with the crystal and theoretical analysis was perfornned for the effectiveness of circular electrode to produce small polarization inversion Next, circular electrode of 2 μm period was produced on the resist patterned by 2-beam laser interference exposure method and the pulse voltage application domain inversion experiment was conducted in order to prove the method. As a result, 2μm periodic domain inversion in a 500 μm thick LN crystal was fabricated. Moreover, though it was a part, … More 0.15 μm domain inversion was achieved using this new method and the effectiveness of the proposed circular for FCE method was proved.2)The relation between specific resistance and polarization inversion characteristic of the crystal : The polarization inversion characteristic was examined by the fabrication of small size domain inversion using the LN crystal with controlled specific resistance, ρ. For black-LN (B-LN) crystal, with ρ value fair orders of magnitude lower than of normal LN crystal, domain inversion threshold voltage (V_<th>) was 〜100V and was proportional to ρ^<1/2>. Moreover, uniform dot patterns were fabricated when 100V was applied to B-LN. It was clarified that small domain inversion structure can be fabricated by applying lower threshold voltage which is 1/100 or less times compared to the normal LN crystal using controlled specific resistance crystals.3)Fabrication of the ridge type optical waveguide using the dicing saw : A 5mm width and 50 mm length rectangular optical waveguide was fabricated using a dicing saw. The rotational speed and the sending speed of the blade were 30,000 rpm and 0.3 mm/sec, respectively. The insertion loss and the propagation loss of the optical waveguide were measured using a He-Ne laser. The measured loss values were 1 dB/cm and 7 dB, respectively. The present characteristics of the optical waveguide are not enough. However, optimized processing conditions could show the possibility of better optical waveguide fabrication. Less