Browsing by Author "Hangyo, M"

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Control of enhanced THz transmission through metallic hole arrays using nematic liquid crystal
(2005-05-30)
Pan, CL
;
Hsieh, CF
;
Pan, RP
;
Tanaka, M
;
Miyamaru, F
We demonstrate frequency tuning of enhanced THz radiation transmitted through a two- dimensional metallic hole array ( 2D- MHA) by controlling the index of refraction of the medium filling the holes and adjacent to the 2D- MHA on one side. The medium is a nematic liquid crystal ( NLC) and its index of refraction is varied using magnetically controlled birefringence of the NLC. With the NLC, the peak transmission frequency of the 2D- MHA shift to the red by 0.112 THz and can be tuned from 0.193 to 0.188 THz. The peak transmittance is as high as 70% or an enhancement of 2.42 times, considering the porosity of the 2D- MHA. As a tunable THz filter, this device exhibits a continuous tuning range of 4.7 GHz, a low insertion loss of 2.35 to 1.55 dB and a quality factor of similar to 4- 5. (C) 2005 Optical Society of America.
Control of THz transmission through two-dimensional metallic photonic crystals
(2005)
Pan, CL
;
Hsieh, CF
;
Pan, RP
;
Tanaka, M
;
Miyamaru, F
We demonstrate frequency tuning of resonantly enhanced THz radiation transmitted through a two-dimensional metallic photonic crystal on a liquid crystalline "substrate".
Terahertz field detection beyond 30 THz by proton-bombarded InP photoconductive antennas
(2005)
Liu, TA
;
Tani, M
;
Nakajima, M
;
Hangyo, M
;
Sakai, K
We show that photoconductive antennas fabricated on proton-bombarded InP (InP:H+) substrates with a proton dosage of 1x10(15) ions/cm(2) are promising for THz detection.
Ultrabroadband terahertz field detection by photoconductive antennas based on multi-energy arsenic-ion-implanted GaAs and semi-insulating GaAs
(2003-08-18)
Liu, TA
;
Tani, M
;
Nakajima, M
;
Hangyo, M
;
Pan, CL
The photoconductive antennas based on multi-energy arsenic-ion-implanted GaAs and semi-insulating GaAs are demonstrated to have a useful bandwidth beyond 20 THz for a gating laser pulse width of 15 fs. The bandwidth and signal-to-noise ratio are compared with those of reference photoconductive antennas based on low-temperature grown GaAs. (C) 2003 American Institute of Physics.
Ultrabroadband terahertz field detection by proton-bombarded InP photoconductive antennas
(2004-06-28)
Liu, TA
;
Tani, M
;
Nakajima, M
;
Hangyo, M
;
Sakai, K
Photoconductive ( PC) antennas fabricated on InP bombarded with 180 keV protons of different dosages (InP:H+) all exhibit a useful bandwidth of about 30 THz, comparable to that of the LT-GaAs PC antenna. The peak signal current of the best InP: H+ device (dosage of 10(15) ions/cm(2)) is slightly higher than that of the LT-GaAs one, while the signal-to-noise ratio (SNR) of the former is about half of that of the latter due to lower resistivity. This suggests that InP: H+ can be a good substrate for THz PC antennas with proper annealing and/or implantation recipe. (C) 2004 Optical Society of America.