Masakatsu Okada

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 .

Optical regenerative oscillation and monostable pulse generation in hybrid bistable optical devices

Abstract Instability in the transient response of hybrid bistable optical devices is discussed. It is applied to determine the precise conditions for optical regenerative oscillation and monostable pulse generation in three types of electrooptic bistable devices. Theoretical results explain well the sequential behaviors of these phenomena.

Tuning of a Dye Laser by a Birefringent Fabry-Perot Etalon

It is shown that a birefringent Fabry-Perot etalon, which has a simple configuration similar to Lyots filter except for mirror coatings on the end-faces of birefringent crystal, is useful for tuning of dye lasers because of the high finesse realized by two stages of commonly used Fabry-Perot etalons. Experimental tuning characteristics of PbMoO(4) and LiNbO(3) birefringent Fabry-Perot etalons in a pulsed dye laser, pumped by the second harmonic of a repetitively Q-switched Nd:YAG laser, are in agreement with the theory.

Multi-Functional Electrooptic Device with Feedback

The theoretical and experimental examination of an electrooptic device with feedback are discussed in the paper. It is shown that many functions such as multistability, hysteresis, differential gain and limiter action are possible, on the characteristics of the optical output power versus input power, depending on the feedback gain and phase retardation. The examination of the dependence of the optical output power on phase retardation indicates that more efficient light modulation and switching may be achieved by using this device than by using the conventional light modulator. In addition, hysteresis was observed in the relation between optical output power versus phase retardation at the higher input range.

Reduction of the switching energy in electrooptic bistable devices

Abstract It is described that the switching may be achieved more quickly by an optical input power smaller than the critical power in an electrooptic bistable device having two feedback voltages with different time constants, compared with the conventional bistable optical devices. The reduction of switching energy becomes possible by making the device appropriately unstable. The effects of the optical input power and ratio of time constants on the switching time are discussed.

Tilted birefringent Fabry-Perot etalon for tuning dye lasers.

A tilted birefringent Fabry-Perot etalon, which is set at an angle to the axis of the dye laser cavity and rotated about the normal of end-faces of the etalon, allows the dye laser emission to be tuned with very high finesse as obtained by two cascaded conventional Fabry-Perot etalons.

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.

Light modulation by an electrooptic device with feedback

Abstract Light modulation by an electrooptic nonlinear device is examined theoretically and experimentally. Very low voltage light modulation may be achieved in a conventional electrooptic polarization modulator when a signal proportional to the optical output power is fed back to the modulator crystal. Very linear light modulation may also be implemented in the other mode of such a device.