2000 Fiscal Year Final Research Report Summary
Research on digital image conversion by using photon mixing
| Project/Area Number |
10450023
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| Research Category |
Grant-in-Aid for Scientific Research (B).
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Applied optics/Quantum optical engineering
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| Research Institution | TOHOKU UNIVERSITY |
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Principal Investigator |
TANIUCHI Tetsuo Tohoku University, Research Institute of Electrical Communication, Associate Professor, 電気通信研究所, 助教授 (80260446)
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| Co-Investigator(Kenkyū-buntansha) |
ITO Hiromasa Tohoku University, Research Institute of Electrical Communication, Professor, 電気通信研究所, 教授 (20006274)
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| Project Period (FY) |
1998 – 2000
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| Keywords | nonlinear optics / lithium niobate / sum frequency generation / difference frequency generation / terahertz / optical parametric oscillation |
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| Research Abstract |
We have investigated a frequency conversion from infrared to visible spectrum by using a nonlinear photon mixing in nonlintear crystals. To achieve an efficient sum frequency generation (SFG), a phase matching property of LiNbO_3 crystals was studied in detail. Also, we have experimentally investigated the frequency conversion between optical waves and terahertz (THz) waves in a GaP crystal.
1) Frequency conversion from infrared to visible spectrum
We have investigated the phase matching properties for SFG in LiNbO_3, MgO : LiNbO_3, and periodically poled LiNbO_3 (PPLN) crystals. In LiNbO_3 and MgO : LiNbO_3 crystals, the infrared conversion range for SFG is determined mainly by the crystal temperature. On the other hand, we can obtain widely tunable SFG in PPLN because that the quasi-phase-matching can be achieved by controlling the domain period. Infrared radiation woth 1.5-5μm can be converted to the visible in domain-controlled PPLN.We proposed a new structure of the guided-wave SFG for a digital image conversion by digitalizing the infrared image spatially.
2) Frequency conversion between optical and THz waves.
The frequency conversion between optical and THz waves can be possible by SFG and difference frequency generation (DFG). GaP crystal is an attractive material for the frequency conversion because of the large uonlinear optical effect and the low loss property at the THz-wave region. We have found that the collinear phase-matching was achieved by selecting the pumping wavelength at 0.98 μm for SFG and DFG interaction. We developed an optical parametric oscillator (OPO) with KTP crystal at the wavelength range of 0.98 um. Tunable THz waves were successfully generated in the range of 0.5-2.2THz by mixing a dual wavelength OPO output in GaP.
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