Saturation properties of large-aperture photoconducting antennas

Darrow, J. T.; Zhang, Xicheng; Auston, D. H.; Morse, Jeffrey

doi:10.1109/3.135314

Cited by 239 publications

(192 citation statements)

References 21 publications

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“…When the incident laser pulse illuminates the chip, the GaAs photoconductive dipole antenna will radiate THz electromagnetic pulse, as shown in Figure 1 [7]. Through the current surge model [3], the surface current can be expressed as…”

Section: Theoretical Analysismentioning

confidence: 99%

“…According to boundary conditions of the Maxwell's equations, the relationship between and is given by [3] …”

Section: Theoretical Analysismentioning

confidence: 99%

“…Experimental results show that the use of large-aperture photoconductive antenna can generate relatively strong THz radiation. The mechanism can be depicted by the famous current surge model [3]. The model deems that the THz electromagnetic waves are generated by transient current in photoconductive antenna.…”

Section: Introductionmentioning

confidence: 99%

“…The model deems that the THz electromagnetic waves are generated by transient current in photoconductive antenna. Justin T. Darrow [3], A.J.Taylor [4], Sang-Gyu Park [5] and Zhang tongyi [6] discussed the far-field radiation characteristics of the large-aperture THz photoconductive antenna and derived time-domain expression of the THz radiation field. On this basis, the paper further considers the influence of the ratio of luminous flux, carrier lifetime and the incident THz pulses width on the radiation THz pulses in the surface field and in the far field.…”

Section: Introductionmentioning

confidence: 99%

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Study on characteristics of terahertz radiation in the surface and far field generated by large-aperture photoconductive antennas

Chen¹,

Cui²,

Jiang³

et al. 2011

J. Phys.: Conf. Ser.

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Abstract. The time-domain characteristics of terahertz radiations emitted from a biased largeaperture photoconductive antenna trigged by an ultra-short optical pulse are studied. Succinct explicit expressions in the surface field and in the far field for the emitted THz radiation fields are deduced based on the well-known current-surge model. The expressions indicate that the THz radiations in the surface and far fields are mainly affected by the incident light intensity, the incident light wavelength, the carrier relaxation time, the reflectivity illuminated at the photoconductor, the carrier lifetime, and the incident light pulse width. The characteristics of THz radiation in the surface and far fields are discussed, and the phenomena of changes in the radiation peak values, the radiation pulse width, and the rising edges are explained in details. Especially the changes in surface fields are explained with the increasing of the ratio of luminous flux. The numerical results indicate that the emitted THz radiation intensity can be increased by enhancing the ratio of luminous flux, prolonging the carrier lifetime, or reducing the incident light pulse width. To avoid the shielding effect of the radiation field, an effectively method is presented that the intense of the incident laser pulse could be divided into multiple beams with low energy to trigger the photoconductive antenna, thus the THz radiation power can be further increased significantly.

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Section: Theoretical Analysismentioning

confidence: 99%

“…According to boundary conditions of the Maxwell's equations, the relationship between and is given by [3] …”

Section: Theoretical Analysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Study on characteristics of terahertz radiation in the surface and far field generated by large-aperture photoconductive antennas

Chen¹,

Cui²,

Jiang³

et al. 2011

J. Phys.: Conf. Ser.

View full text Add to dashboard Cite

show abstract

“…The THz emission amplitude is believed to be proportional to the local bias electric field in the optical illuminated region [14], whereas the breakdown field of the material limits the maximum applied bias field [15]. That means the material would be damaged when the bias field beyond the material breakdown field, so the breakdown effect is limited by the bias field.…”

Section: Introductionmentioning

confidence: 99%

Enhancing Terahertz Radiation From Dipole Photoconductive Antenna by Blending Tips

Diao¹,

Yang²,

Li³

et al. 2011

PIER Letters

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Abstract-We study the rectangular tips of the dipole photoconductive antenna, which has been widely used for terahertz radiation and detection, with different blend radii effect on the emission performance of terahertz (THz) radiation. For the amplitude of THz radiation pulse is proportional to the local electric field in the gap, the increased maximum bias electric field by blending tips is able to achieve higher THz radiation power. Both considering the influence to the maximum bias electric field and the emission efficiency, the blend radius of the rectangular tips is suggest to be larger than 5 µm and the radiation power is largely enhanced. Comparing to the previous work, our method has better THz radiation performance.

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Terahertz Electric Field Imaging

Zhang

2002

Encyclopedia of Imaging Science and Technology

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Various frequencies are spaced along the frequently used electromagnetic spectrum, including microwaves, infrared, visible light, and X rays. Terahertz radiation between microwave and infrared frequencies lies. In the electromagnetic spectrum, radiation at 1 THz has a period of 1 ps, a wavelength of 300 µm, a wave number of 33 cm −1 , photon energy of 4.1 meV, and an equivalent temperature of 47.6 K. In the same way that visible light can create a photograph, radio waves can transmit sound, and X rays can see shapes within the human body, terahertz waves (Trays) can create pictures and transmit information. Until recently, however, the very large terahertz portion of the spectrum has not been particularly useful because there were neither suitable emitters to send out controlled terahertz signals nor efficient sensors to collect them and record information. Recent developments in terahertz time‐domain spectroscopy and related terahertz technologies now lead one to view the world in a new way. As a result of developing research, terahertz radiation now has widespread potential applications in medicine, microelectronics, agriculture, forensic science, and many other fields. Three properties of THz wave radiation triggered research to develop this frequency band for applications and are discussed. Coherent terahertz time‐domain spectroscopy that has an ultrawide bandwidth provides a new method for characterizing the electronic, vibronic, and compositional properties of solid, liquid, and gas phase materials, as well as flames and flows. In theory, many biological and chemical compounds have distinct signature responses to terahertz waves due to their unique molecular vibrations and rotational energy levels, this implies that their chemical compositions might be examined using a terahertz beam. A T‐ray imaging modality would produce images that have “component contrast” enabling analysis of the water content and composition of tissues in biological samples. Such capability presents tremendous potential to identify early changes in composition and function as a precursor to specific medical investigations and treatment. Moreover, in conventional optical transillumination techniques that use near‐infrared pulses, large amounts of scattering can spatially smear out the objects to be imaged. T‐ray imaging techniques, due to their longer wavelengths, can provide significantly enhanced contrast as a result of low scattering (Rayleigh scattering).

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Saturation properties of large-aperture photoconducting antennas

Cited by 239 publications

References 21 publications

Study on characteristics of terahertz radiation in the surface and far field generated by large-aperture photoconductive antennas

Study on characteristics of terahertz radiation in the surface and far field generated by large-aperture photoconductive antennas

Enhancing Terahertz Radiation From Dipole Photoconductive Antenna by Blending Tips

Terahertz Electric Field Imaging

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