Kyoto University

Japan Science and Technology Agency

Takuya Inoue

Susumu Noda

Menaka De Zoysa

Takashi Asano

Masahiro Yoshida

Keisuke Kitano

Anqi Ji

Tatsuya Shibahara

Katsuyoshi Suzuki

Kenji Ishizaki

A two-dimensional photonic-crystal surface-emitting laser includes an active layer, a two-dimensional photonic crystal, and electrodes. The two-dimensional photonic crystal contains a plate-shaped base material arranged on one side of the active layer and different refractive index portions arranged at lattice points of a predetermined lattice in the base material and having a refractive index different from that of the base material, a band edge frequency for each position in an electric current supply region, which is at least a part of the two-dimensional photonic crystal, is monotonically increased in one direction parallel to the base material. Such a two-dimensional photonic crystal occurs when the different refractive index portion has a refractive index smaller than that of the base material, a filling factor, which is a ratio of a volume occupied by the different refractive index portion in a unit lattice constituting the lattice, is monotonically increased in the one direction.

Two-dimensional photonic-crystal surface-emitting laser

A two-dimensional photonic-crystal surface-emitting laser includes an active layer; and a photonic-crystal layer including a two-dimensional photonic-crystal light-amplification portion that is a first two-dimensional photonic-crystal region provided in a plate-shaped base body disposed on one side of the active layer, and includes an amplification-portion photonic band gap which is a photonic band gap formed between two photonic bands having a band edge at a predetermined point in a reciprocal lattice space, and a two-dimensional photonic-crystal light-reflection portion that is a second two-dimensional photonic-crystal region provided around the two-dimensional photonic-crystal light-amplification portion, and includes a reflection-portion photonic band gap which is a photonic band gap formed between two photonic bands having a band edge at the predetermined point of the reciprocal lattice space, wherein energy ranges of the amplification-portion photonic band gap and the reflection-portion photonic band gap partially overlap and are different.

A thermal radiation light source includes a laminated body including m quantum layers laminated where m is an integer of 2 or more, including an n-layer and a p-layer sandwiching the quantum layers from both sides in the laminating direction, the n-layer made of an n-type semiconductor and the p-layer made of a p-type semiconductor; a voltage applying unit for the m quantum layers is directly or indirectly connected to the n-layer and p-layer sandwiching each layer applying a voltage for moving to the n-layers or p-layers a charge; a voltage switching unit switches ON/OFF of application of the voltage to the m quantum layers; and a photonic crystal portion disposed in the laminated body or adjacent to the laminated body, so that lights of m wavelengths resonate, the lights of the m wavelengths generated in the m quantum layers corresponding to transition energy between subbands in the quantum layer.

Thermal radiation light source

A thermal emission source capable of switching the intensity of light at a high response speed similarly to a photoelectric conversion element. A thermal emission source includes: a two-dimensional photonic crystal including a slab in which an n-layer made of an n-type semiconductor, a quantum well structure layer having a quantum well structure, and a p-layer made of a p-type semiconductor are stacked in the mentioned order in the thickness direction, wherein modified refractive index areas (air holes) whose refractive index differs from the refractive indices of the n-layer, the p-layer and the quantum well structure layer are cyclically arranged in the slab so as to resonate with a specific wavelength of light corresponding to a transition energy between the subbands in a quantum well in the quantum well structure layer; and a p-type electrode and an n-type electrode for applying, to the slab, a voltage which is negative on the side of the p-layer and positive on the side of the n-layer.

Growing community of inventors

Kyoto, Japan

Takuya Inoue