Quantum Technology and Advanced Sensing

Our interests can be divided into two parts. One is to understand the interplay between confined electronic states and electromagnetic waves in semiconductor quantum structures and atomic layer materilas. On the basis of such fundamental researches, we develop single terahertz (THz) photon detectors and its measurement schemes. Another interest is to create a unique medical or industrial sensing method using ultrasonic technology. We develop "acoustically stimulated electromagnetic (ASEM) method", in which weak EM radiation induced by ultrasonic excitation is detected. This new method will be used for medical diagnosis or nondestructive industrial sensing.

Terahertz wave:Challenging the electromagnetic spectrum where we have not dealt with yet

Terahertz wave (Terahertz light) is an electromagnetic wave with a frequency of 1 terahertz (1 THz = 10^{12} Hz) band. The frequency is too high to treat it with electronics, and the wavelength is too long to treat it with optics. Although various applications are expected from ultrahigh-speed information communication to biomedical sensing, the terahertz region is still an undeveloped area that has not been able to fully cope with electronics and optics in the past. Utilizing the semiconductor quantum structure and atomic layer materials, we provide the fundamental technology of single-photon THz detector, THz emitter and quantum information devices.

New ultrasound technique: Imaging of electromagnetic properties via acoustic excitation

Ultrasound imaging technique is widely applied as noninvasive probe to human bodies and material structures. One important advantage of the technique is that elastic waves are capable of propagating through opaque substances such as human bodies, metals, and concrete blocks, in which light does not propagate. Despite this advantage, the majority of existing applications are restricted to diagnosing elastic properties of the targets, viz., electromagnetic properties are not probed. We have newly developed a unique technique capable of imaging electric and magnetic properties of matters through acoustic excitation (ASEM method). This new method provides valuable information such as degradation of collagen in bone, fibrosis of organs and residual stress of steel products and so on. We have a dream to contribute to medical and industrial innovation through this new sensing technique.

What's NEW?

Oral Presentation, K. Ikushima, "Acoustically stimulated electromagnetic response in biomedical tissues", IEEE IUS (Kobe, Japan).
Poster presentation, Y. Suzuki, "Stress dependence of magnetic hysteresis properties through acoustically stimulated electromagnetic response in steel", IEEE IUS (Kobe, Japan).
Invited Talk in SPIE Optics and Photonics Symposium. K. Ikushima, "Quantum dot THz detectors and applications for imaging" (San Diego, USA)
Poster presentation in ICPS2018. K. Ikushima et al., "Observation of Landau-level emission in current-injected graphene" (Montpellier, France)
Paper accepted. J. Yotsuji et al., "Flaw detection for thin sheet using acoustic stimulated electromagnetic wave technique" 鉄と鋼 Vol. 104, No. 12 (Japanese).
Paper published. H. Yamada et al., "Phase sensitive detection of acoustically stimulated electromagnetic response in steel" Jpn. J. Appl. Phys. 57, 07LB09 (2018).
Paper published. D. Nakagawa et al., "Terahertz response in the quantum Hall effect regime of a quantum-well based charge sensitive phototransistor" Jpn. J. Appl. Phys. 57, 04FK04 (2018).
Paper published. Chiu-Chun Tang et al, "Quantum Hall dual-band infrared photodetector" Phys. Rev. Applied 8, 064001 (2017).