Semiconductor lasers have contributed to modern society over a wide range of fields, particularly tele- and data-communications and optical storage. To date, much interest has been devoted toward expanding the utility of semiconductor lasers for these fields by widening their range of accessible wavelengths and improving their modulation speed.

On the other hand, with regard to high-power applications, semiconductor lasers have had difficulty simultaneously achieving high output powers and high beam qualities which are important for Smart Mobility and Smart Manufacturing. So, their development has lagged behind that of other lasers, such as CO₂ and fiber lasers. Moreover, as with many other lasers, semiconductor lasers have not been capable of on-chip beam pattern, polarization, and direction control; these functionalities required the addition of external elements which forfeits the advantage of compactness for which semiconductor lasers are renowned.

Now, with the development of photonic-crystal surface-emitting lasers (PCSELs) which we invented in 1999, this paradigm is expected to change; PCSELs are currently attracting much attention for their simultaneous achievement of high output power and high beam quality (=high brightness) as well as their exhibition of functionalities that are not easily achievable with other types of lasers, such as polarization and beam-pattern control as well as on-chip beam-direction control, which eliminates the need for bulky external optics.

To strengthen the research and development of PCSELs and make a social application of PCSELs, we recently established the Center of Excellence (COE) for PCSELs in Photonics and Electronics Science and Engineering Center (PESEC) in Kyoto University. The COE is currently operated under the project of Council for Science, Technology and Innovation (CSTI), Cross ministerial Strategic Innovation Promotion Program (SIP), “Photonics and Quantum Technology for Society 5.0”, under the CREST program (JP MJCR17N3) commissioned by the Japan Science and Technology Agency (JST), Japan.

“Now, with the development of Photonic-Crystal Surface-Emitting Lasers (PCSELs), which we invented in 1999, the paradigm is certainly changing; PCSELs are attracting much attention for their simultaneous achievement of high output power and high beam quality (=high brightness), as well as their exhibition of functionalities that are not easily achievable with other types of lasers, such as polarization, beam-pattern control, and on-chip beam-direction control, which eliminates the need for bulky external optics.“