LED and laser displays are attractive because of their low electric power consumption and the wide range of colors that can be realized. The high efficiency and small etendue of laser sources are advantageous for downsizing display systems. In this article, laser displays using highly efficient RGB lasers are reviewed. Also laser projection systems using these lasers and illumination optics achieving speckle noise reduction are introduced.

The high-power operation of red (635 nm) and blue (445 nm) light semiconductor lasers was achieved using GaInP and GaInN compound systems, respectively. In this article we summarize the technical improvements in these lasers that have enabled them to achieve high-power operation. On the basis of recently acquired knowledge on laser operation, recent progress, technical issues, and the evolution of green light semiconductor lasers are reviewed. Very recently, the room-temperature continuous-wave operation of GaInN-based green light lasers has been achieved. However, the threshold current density of the lasers continuously increased with wavelength above 500 nm. Various technical issues of the lasers must still be solved to realize their high-power operation. Thus, research on other materials with the aim of achieving green light lasers, that is, GaN nanocolumns and novel II-VI compounds on InP substrates, is also described.

Projectors are widely used in PC presentations and home theater, and their brightness and image quality have been improving. In addition, their portability is increasingly required, which depends on the development of miniaturization technologies for optical systems and the progress of new light sources such as LEDs and lasers. In this article, we give a broad overview of trends in the development of these projectors and consider the problems and potential of using semiconductor lasers for projection displays.

We have been developing a compact, highly efficient, and high-power green laser for application to a laser TV. To apply proximity coupling to the three essential devices of a planar-waveguide pump LD, a solid-state laser, and a wavelength converter, we have developed a miniaturized laser with a volume as small as 10cm³. This laser provides an output power of 10W with an electrical efficiency of as high as 20%. In addition, the output power degradation is less than 20% from its maximum over a temperature range of 40°C for the above essential devices, which eliminates the need for precise temperature control of the laser. The first laser TV named ‘LaserVue’, which has three primary colored lasers as well as a green laser developed by us, provides an ultra wide color gamut with twice the range of colors as a conventional LCD-TV, a 65-inch wide screen that is only 255mm thick, and a low power consumption of 135W, one-third of that of a conventional LCD-TV.

Most of the 3D displays reported to date have been pseudo-3D images on 2D planes that utilize the human binocular disparity. However, these displays have many drawbacks such as the limitation of the visual field and the physiological displeasure due to the misidentification of virtual images. We have developed a 3D display that utilizes the phenomenon of plasma emission near the focal points of a focused laser beam. By controlling the positions of the focal points, real 3D images constructed of dot arrays were displayed in air (3D space).

It is necessary to decrease the power-supply voltage to reduce the power consumption of scaled CMOS devices. The major difficulty in preventing this power reduction is the increasing variation of V_th with scaling. We proposed a SOTB (Silicon on thin buried oxide) structure to solve this problem. This structure, a fully depleted silicon on insulator (FDSOI) with an ultrathin (10 nm) buried-oxide (BOX) layer, has very small variation of V_th owing to the low impurity density in its channel region and its excellent short-channel-effect immunity, and is also capable of back-gate bias control. In this report, the significant reduction in the variation, the low-voltage (〜0.6 V) operation of SRAM, the back-gate bias control, and the estimation of power reduction due to the reduced variation are demonstrated. A future vision on the SOTB is also discussed.

The use of glass capillary optics for the effective focusing of high-energy ion beams is described. Its fabrication, features and various applications are surveyed. Typically, a glass capillary with an inlet diameter of 1 mm and outlet diameter of 10μm can focus a 2 MeV-10 nA He ion beam into a micro beam having 10μm diameter and 0.1 nA without any energy loss. This finding has several similarities with the channeling phenomenon of fast ion beams in crystal lattices. The ion beam is steered by small angle scattering collisions and reflected by the inner surface of the glass capillary. In this sense the capillary acts as an artificial channel. Analogous to actual channeling, the incident ion beam is required to be exactly parallel to the capillary axis.

From everyday experience as well as from scientific literature, it is known that light transports energy. In this article, the basic concepts of electromagnetic energy stored in space and its flow are described. In particular, a fundamental aspect of the power density of light is discussed in detail. In opaque materials, light energy is lost and converted into thermal or electrical energy through light-matter interaction. In energy conversion applications, conversion efficiency and speed are key parameters, which should be optimized on the basis of the understanding of the change in power density during light propagation.