In this paper, we report the recent progress in ultrashort-pulse generation in the relatively low-power region, terawatt-class high-power amplifiers and attosecond-pulse generation in high-order harmonics. In the visible region, pulses are now approaching the monocycle regime by using innovations such as chirp mirrors and adaptive optics. Ti:sapphire amplifiers are now being replaced by optical parametric amplifiers because of their much broader spectrum. The generation and measurement of attosecond pulses have already been achieved, and efforts towards sub-100 attosecond pulses are now being made.

We describe the adiabatic manipulation of a Raman process in a far-off resonant three-level system and its application to nonlinear optical processes. We show that near-maximal Raman coherence is produced through the adiabatic process, enabling efficient nonlinear optical processes that are not restricted by phase matching. We also show some of recent studies in this subject that are broad Raman sideband generation covering infrared to deep-ultraviolet regions and its application to ultrashort-pulse generation based on Fourier synthesis of the Raman sidebands.

We report on novel techniques used for measurement of an attosecond pulse train (APT) formed by the Fourier synthesis of high-order harmonic fields. Direct observation of the train feature of the APT revealed two kinds of autocorrelation signals, which are yielded via nonlinear interaction of the APT with an atom or a molecule, revealing the intrinsic characteristics of the APT.

The current status of the electronics and photonics convergence on a Si CMOS platform is reviewed. The interconnection bottleneck of microprocessor chips is slowing down the development of our Internet-based society. In the present paper we describe Si photonics and on-chip interconnection that will break through the bottleneck and enhance the figure of merit of communication and computation systems.

We have demonstrated phase-coherent multicolor femtosecond-pulse generation by two methods. One is based on self timing-synchronized two-color lasers consisting of Ti:sapphire and Cr:forsterite lasers. The other uses a femtosecond optical parametric oscillator. In both cases, the optical phase relations were locked tightly.

A new technique, the self-recognition of feedback chirp compensation, which enables us to overcome problems in conventional optical pulse compression and generate a quasi-monocycle single pulse at a 1 kHz repetition rate, is introduced. The generation of a 1.5 cycle, 2.8 fs transform-limited pulse with a spectral broadening from 460 to 1060 nm is demonstrated. Furthermore, it is shown that the application of this technique for induced-phase modulated pulses enables us to generate 1.3 cycle, 2.6 fs optical pulses with a peak power of 1.4 GW. Finally, the future direction of the technology of such extremely short optical pulses is summarized briefly.

In this paper, we review recent progress in nanophotonic devices using optical near-field interaction. ZnO nanocrystallites are potentially ideal components for realizing room-temperature operation of nanophotonic devices because of their high exciton-binding energy and great oscillator strength. To confirm this promising optical property of ZnO, we report the near-field time-resolved spectroscopy of ZnO nanorod double-quantum-well structures (DQWs). First, we observed nutation of the population between the resonantly coupled exciton states of DQWs, in which the coupling strength of the near-field interaction was found to be decreased exponentially as the separation increased. Furthermore, we successfully demonstrated the switching dynamics of a dipole-forbidden optical energy transfer among resonant exciton states. Our results provide criteria for designing nanophotonic devices.

When a laser beam is focused into molecular hydrogen, multifrequency laser emission with equal frequency spacing is generated by a phenomenon based on Raman scattering. These emission lines are automatically phase-locked to generate an ultrashort optical pulse. When a continuous-wave laser is focused into molecular hydrogen in a high-finesse cavity, a continuous-wave multifrequency laser emission with equal frequency spacing can be generated, leading to a train of pulses caused by coherent superposition of the emission lines. This laser has the potential to be used as a standard-frequency light source as well as in ultrafast optical communication.

The spectral structure of a mode-locked laser can be used as a ruler of optical frequency. Since the advent of the frequency comb technique, it has been used to produce many interesting results in the fields of basic physics and telecommunications, as well as metrology. We will explain several results that have been obtained by the frequency comb technique at National Institute of Advanced Industrial Science and Technology(AIST).

In this paper, we present the GxL one-dimensional spatial light modulator developed for the Laser Dream Theater, Expo 2005, Aichi, Japan. The optical diffraction device was fabricated using MEMS(Micro Electro Mechanical System) technology, and the blazed ribbon structure has been introduced. By optimizing the ribbon shape, we succeeded in developing a device with a high optical efficiency of over 70%, and a high contrast ratio of over 10000:1. The reliability of the device is also discussed.

We introduce and overview recent topics related to OCTA (the Open Computational Tool for Advanced material technology). OCTA is an integrated simulation system for soft materials developed by a joint project between industry and academia funded by NEDO (the New Energy and Industrial Technology Development Organization) and METI (the Ministry of Economy, Trade and Industry). The OCTA system was opened for public in April 2002, and it has been growing continuously. OCTA consists of four simulation programs (COGNAC, PASTA, SUSHI, MUFFIN) and a simulation platform (GOURMET), and is designed for collaborative operations of multi-programs. The features of each simulation program and recent samples of the applications are introduced in this article.