Hisataka Takenaka

Realization of polymeric optical integrated devices utilizing organic light-emitting diodes and photodetectors fabricated on a polymeric waveguide

Direct fabrication of organic light-emitting diodes (OLEDs) and organic photodetectors (OPDs) on polymeric substrates, i.e., polymeric waveguide substrates to form flexile optical integrated devices is demonstrated. The OELD and OPD were fabricated by organic molecular beam deposition (OMBD) technique on a polymeric or a glass substrate, for comparison. The device fabricated on a polymeric substrate shows similar device characteristics to that on a glass substrate. Optical signals of faster than 100 MHz have been created by applying pulsed voltage directly to the OLED utilizing diamine derivative, or rubrene or porphine doped in 8-hydoxyquinolinum aluminum derivatives, as an emissive layer. Electrical signals are successively converted to optical signals for optical transmission of moving picture signals with OLED fabricated on a polymeric waveguide. OPDs utilizing phthalocyanines derivatives with superlattice structure provide increased pulse response with input optical signals, and the OPD with the cutoff frequency of more than 5 MHz has been realized.

Multi-layered flyer accelerated by laser induced shock waves

Multi-layered flyer (aluminum–polyimide–tantalum) is designed as a high speed flyer making use of shock impedance matching and reverberation techniques. The designed three layered targets have been irradiated using a 20 J laser beam. Flyer velocities are measured by observing the flyer impact emissions on glass step targets within a 500 μm laser focal spot at laser intensities 5×1012–2×1013 W/cm2. Thin (0.5–1.0 μm) Ta layers of the flyers are accelerated via shock reverberations between the thick polyimide and thin Ta layers for the first time using laser induced shock waves. Their velocities are measured to be more than 13 km/s with a good hydrodynamic stability. The obtained velocity is faster than the ones obtained by a conventional flyer method such as a double gas gun.

Transient Properties of Organic Electroluminescent Diode Using 8-Hydroxyquinoline Aluminum Doped with Rubrene as an Electro-Optical Conversion Device for Polymeric Integrated Devices

We describe modulation characteristics of organic light-emitting diodes (OLEDs) using 8-hydroxyquinoline aluminum (Alq3) as an electro-optical conversion device for polymeric integrated devices. Optical pulses of more than 100 MHz were created by directly modulating a yellow emitting OLED with rubrene doped in Alq3 as an emissive layer which has the advantages of low propagation loss in the polymer waveguide and high emission intensity. We demonstrate that the OLEDs can be applied to fields of optical communication as electro-optical conversion devices for transmitting the signals of moving images.

Organic electroluminescent diodes as a light source for polymeric waveguides - toward organic integrated optical devices

Abstract We fabricated organic electroluminescent diodes (OELD) on a polymeric optical waveguide for use as an optical interconnect in data communication systems. We fabricated the OELDs on an ITO sputtered polymeric waveguide with a 45° mirror by vacuum deposition. These OELDs, with an emission peak center at 520 nm, consist of a N,N′-diphenyl-N,N′-(3-methylphenyl)-1,1′-biphenyl-4,4′-diamine (TPD) as a hole transporting layer and 8-hydroxyquinolie aluminum (Alq3) as an emissive layer. We estimated the propagation losses of the waveguide to be 1.35 dB/cm at 520 nm. The optical pulses of faster than 5 Mb/s have been generated from the OELD. We discuss the characteristics of the OLED as regards its use as a light source for polymeric waveguides.

Laser-Induced Shock Compression of Tantalum to 1.7 TPa

An extremely high pressure (1.74±0.22 TPa) was generated in Ta by using strong shock waves driven by direct irradiation of laser beams from the GEKKO XII glass laser system. The shock velocity was measured directly and the particle velocity and pressure were obtained using an impedance-matching technique by considering the intensity profile of the laser beams.

Spatial Coherence Measurement of 13.9 nm Ni-like Ag Soft X-Ray Laser Pumped by a 1.5 ps, 20 J Laser

In this paper, we report the first measurement of the time-integrated spatial coherence of the Ni-like Ag X-ray laser at 13.9 nm pumped by a 1.5 ps, 20 J Nd glass laser, in which the transient collisional excitation (TCE) pumping scheme is realized. The time-integrated complex coherence factor (CCF) of the X-ray laser has been determined from partially coherent diffraction patterns of a multislit array placed 1 m away from the X-ray laser source. The transverse coherence lengths in the directions horizontal and vertical to the Ag target surface are estimated respectively to be within 110 µm to 140 µm at a position 1 m from the X-ray laser source. We tried to explain the profile of the CCF with a quasi-monochromatic incoherent source model with various profiles.

NEAR FIELD IMAGING OF THE TRANSIENT COLLISIONAL EXCITATION Ni-LIKE Ag X-RAY LASER

The spatial profile of the transient collisional excitation Ni-like Ag X-ray laser in various plasma lengths was observed using the near field imaging method. The gain region was the size of 50 μm and 30–50 μm distant from the target surface. The shapes of the gain region were crescent shape or consisted of two spots.

Intense Nickel-like Neodymium X-Ray Laser at 7.9 nm with a Double-Curved-Slab Target

We have demonstrated triple-pulse lasing combined with an X-ray mirror with 4 pumping pulses in Ni-like Nd at 7.9 nm. Intense triple-pulse X-ray laser radiation has been generated with a double-curved-slab target, which was irradiated with laser pulses of quasi-traveling wave configuration, using cylindrical lens arrays for uniform pumping. An order of magnitude higher X-ray laser pulse energy was observed along the forward-traveling wave direction compared to the backward-traveling wave direction. Output energy in the forward direction was estimated to be ~40 µJ.

Generation of intense x-ray laser radiation at 8 nm in Ni-like Nd ions

Results of the joint experiment between ILE Japan and NLHPLP/IAPCM China are reported. New optics for improved line focusing, a cylindrical lens array and a deformable mirror, were used in irradiation of x-ray laser targets. Double-pass amplification at 7.9 nm has been demonstrated. Strong lasing at 7.9 nm with approximately 100 (mu) J output energy has been obtained in Ni-like Nd ions by quasi-traveling wave pumping of double targets.

Hugoniot measurements for polyimide with laser and explosives

Equation-of-state measurements for a polyimide are presented. High-power KrF laser and chemical explosive-driven experiments provided Hugoniot data on the polyimide up to about 65 GPa. Conventional reflected-light measurements in the explosive experiments and velocity interferometry measurements in the laser experiments were performed. From both laser and explosive results the change of Hugoniot was indicated at near 30 GPa.