We report a simple method of creating terahertz waves by applying the photo-Dember effect in a (100)-oriented InAs film coated onto the 45-degree wedged-end facet of an optical fiber. The terahertz waves are generated by infrared pulses guided through the optical fiber which is nearly in contact with a sample and then measured by a conventional photo-conductive antenna detector. Using this alig...

In future wireless communication networks at terahertz frequencies, the directivity and beam profile of emitters are highly relevant since no additional forming optics can be placed in free-space between emitter receiver. We investigated radiation pattern polarization broadband continuous-wave (cw) experimentally by numerical simulations 100 GHz 500 GHz. The indium phosphide (InP) photodiodes w...

We describe and discuss near-field terahertz wave imaging with a dynamic aperture created on a semiconductor wafer. The spatial resolution of a near-field terahertz wave imaging system with a dynamic aperture created on a GaAs wafer is determined by the diameter of the gating-beam-induced thin photocarrier layer. With a dynamic aperture created on a GaAs wafer, we have achieved a subwavelength ...

We demonstrated fast three-dimensional transmission terahertz computed tomography by using real-time line projection of intense terahertz beam generated by optical rectification in lithium niobate crystal. After emphasizing the advantage of intense terahertz pulse generation for two-dimensional spatio-temporal terahertz imaging, peak-to-peak amplitudes of pulsed terahertz electric field have be...

An accurate and direct measurement of the energy distribution of a low repetition rate terahertz electromagnetic pulse is challenging because of the lack of sensitive detectors in this spectral range. In this paper, we show how the total energy and energy density distribution of a terahertz electromagnetic pulse can be determined by directly measuring the absolute electric field amplitude and b...

OBJECTIVE To elucidate the radionuclides and radiochemical impurities included in radiosynthesis processes of positron emission tomography (PET) tracers. METHODS Target materials and PET tracers were produced using a cyclotron/synthesis system from Sumitomo Heavy Industry. Positron and γ-ray emitting radionuclides were quantified by measuring radioactivity decay and using the high-purity Ge d...

A device for holding biomolecule samples on a membrane allows scanning using terahertz frequency waves. Such scanning has previously been difficult due to the strong attenuation of terahertz frequency waves by water. Several types of biomolecules were scanned using terahertz time domain spectroscopy (TDS), and the data showed clear differences in transmittance among the samples. This membrane d...

The authors demonstrate the generation of multicycle narrow-bandwidth terahertz pulses in periodically inverted GaAs structures using optical rectification of 2 m, 100 fs pump pulses. Three different types of orientation-inverted samples are employed: optically contacted multilayer, orientation-patterned, and diffusion-bonded GaAs. The terahertz pulses are characterized by two-color pump at 2 m...

Three-dimensional terahertz computed tomography has been used to investigate dried human bones such as a lumbar vertebra, a coxal bone, and a skull, with a direct comparison with standard radiography. In spite of lower spatial resolution compared with x-ray, terahertz imaging clearly discerns a compact bone from a spongy one, with strong terahertz absorption as shown by additional terahertz tim...