Shogo Ieiri

Second harmonic generation by periodic laminar structure of nonlinear optical crystal

Abstract The phase-matched second harmonic generation by periodic structures composed of laminae of nonlinear optical crystals has been studied experimentally. It is shown that the intensity of the second harmonic is approximately proportional to the square of the number of laminae under phase-matched condition, which is satisfied over a broad frequency range by the variation of the angle of incidence when a laminar structure with a period much larger than the coherence length is used.

Electronic tuning of dye lasers by an electrooptic birefringent Fabry-Perot etalon

Abstract An electrooptic birefringent Fabry-Perot etalon is described for a wavelength selector of dye lasers. The laser emission was electronically tuned with a linewidth of several angstroms over 135 A. This was achieved by changing the applied voltages from -1.2 to +1.2 kV to the etalon constructed from a 3.6 mm long, LiTaO 3 crystal.

Refractive indices of paratellurite and lithium iodate in the visible and ultraviolet regions

Abstract The refractive indices of TeO 2 and LiIO 3 have been measured in the wavelength region between 0.3547 μm and 0.6438 μm by the method of minimum deviation. A thin fluorescent screen has been set at the focal plane of the objective of telescope to observe the ultraviolet light, which was obtained by sum-frequency mixing between a Nd:YAG laser and a tunable dye laser. The accuracies of the data are ± 2.1 × 10 -4 in TeO 2 and ± 2.5 × 10 -4 in LiIO 3 .

General Effects of the Symmetry and Orientation of Crystal on the Second and Third Order Nonlinear Optical Polarizations

This paper describes the general effects of the symmetry and orientation of a crystal on the second and third order nonlinear optical (NLO) polarizations. The results, in which the contributions from the Kleinman forbidden coefficients and the antisymmetric components of the NLO polarizability tensors are taken into consideration, are applicable to the estimation of the NLO polarization in all the NLO devices and to measure the magnitude and sign of the NLO coefficient.

The measurement of the antisymmetric components of nonlinear optical susceptibilities of TeO2 crystal

The antisymmetric components of the second‐order nonlinear optical susceptibility of TeO2 crystal have been measured by the process of sum‐frequency mixing between the laser beams at the wavelengths of 1.064 and 0.532 μm. The experimental results were χ123/ (χ123+χ132) =0.59, χ132/(χ123 +χ132) =0.41, and χ312/(χ123+χ132) =−χ321/(χ123+χ132) =−0.18, which imply that χ123 and χ132 are slightly asymmetric and χ312 and χ321 are antisymmetric in the second and third suffices. It is thus concluded that the contribution of the antisymmetric component to the signal at the sum frequency may be comparable with that of the symmetric one forbidden by the Kleinman symmetry relation. Moreover, the symmetric and antisymmetric components of the nonlinear optical polarizabilities of the bond Te‐O have been estimated in terms of the scheme of bond additivity by assuming a bond symmetry ∞.

Low Frequency Noise in Unlocked Multimode He-Ne Lasers

The properties of the low frequency noise which appeared in unlocked multimode He-Ne lasers are investigated experimentally. It is found that the intensity of a mode fluctuated with opposite phase with respect to the adjacent modes. This behavior is discussed from the points of view of the mode competition and combination tones based on Lambs theory.