Dr. Kenichi Iga wins awards in the field of lasers

Dr. Kenichi Iga (85), Professor Emeritus at Tokyo University of Science, has been awarded the 2025 Honda Prize. The Honda Foundation announced that the award recognizes his outstanding contributions in proposing and advancing the commercialization of “surface-emitting lasers.” This type of semiconductor laser, characterized by its miniaturization, high-density integration, and low power consumption, has significantly propelled the development of optoelectronic technologies in the fields of communications and sensors.

A semiconductor laser is a device that emits laser light by passing an electric current through a semiconductor. An n-type semiconductor and a p-type semiconductor form a pair, and at their junction, excess electrons from the n-type move to areas where the p-type lacks electrons. At this moment, the electron energy converts into light. This light is reflected and amplified by two mirrors at the junction and is emitted as laser light.

In the mid-1970s, with the advent of optical fiber, development of semiconductor lasers accelerated toward the practical application of optical communications. The initial "edge-emitting laser" emitted light parallel to the semiconductor substrate surface and had drawbacks including complex manufacturing processes and wavelength instability.

In 1977, when Dr. Iga was an Assistant Professor at Tokyo Institute of Technology (now Institute of Science Tokyo), he conceived the surface-emitting laser, which emits light perpendicular to the substrate surface, inspired by the idea of "standing up what had been lying down." It offers wavelength stability, compact size, high-density integration capability, ease of mass production, low power consumption, and good compatibility with optical fibers. In 1978, he presented the concept and fabrication method at academic conferences and in papers. Despite widespread skepticism about its feasibility, Dr. Iga's research group persevered through trial and error. In 1988, Dr. Fumio Koyama (now Professor Emeritus at Institute of Science Tokyo) achieved the world's first continuous laser emission at room temperature.

The surface-emitting laser attracted worldwide attention, and from the late 1990s onward, many companies advanced research and development. It has been adopted for ultra-high-speed, large-capacity communications in data centers and LANs (Local Area Networks), as well as for computer mice, laser printers, and three-dimensional facial recognition in smartphones. "LiDAR," a sensor that uses lasers to detect the distance and shape of objects, has been installed in robot vacuum cleaners and is considered essential for the practical application of autonomous driving. In medicine, it has been put to practical use as the laser for optical coherence tomography (OCT), which images cross-sections of the retina. Dr. James Fujimoto of the United States, who developed OCT technology, received the Honda Prize last year.

The market for surface-emitting lasers is estimated at 4 billion dollars. Related research papers worldwide exceed 60,000, making significant contributions to the development of the optoelectronics field. Dr. Iga served as President of Tokyo Institute of Technology from 2007 to 2012.

The Honda Foundation announced the laureate on the 9th of last month. The award ceremony will be held in Tokyo on November 17, with a prize of 10 million yen.

Source: Science Japan