Application of Terahertz Pulse Time-Domain Holography for Phase Imaging

Abstract

Terahertz pulse time-domain holography (THz PTDH) is the powerful technique for high-resolution amplitude and phase THz imaging that allows mapping spectroscopic information across the imaged object. In this paper, we consider most sought after applications of phase imaging provided by this technique and experimentally demonstrate the ability of the method to reconstruct smooth and stepped relief features of an object that is transparent in THz region. Unlike the amplitude distribution, which does not contain any significant information in this case, phase distribution not only reveals the object qualitatively, but also allows the reconstruction of the object thicknesses pattern, even in low signal-to-noise registration conditions. Main limitations of the proposed method, such as transverse resolution and low signal-to-noise environment are carefully studied and mitigated.

Detection of the polarization spatial distribution of THz radiation generated by two-color laser filamentation

“…The spatial dependence of the THz field polarization was measured by moving the diaphragm (D), connected to a THz polarizer (THzP) (wire grid) placed after the Teflon filter inside the collimated beam. Such an approach has been shown previously [3,28], even though it exhibits faster fall-off of the registered signal when moving from the center to the edge owing to the change of the angle between the signal wave vector and the optical axis. The projection of the signal is proportional to the cosine of this angle.…”

“…Besides, the THz field propagation from the filament had a conical structure [29] that created a "donut" vortex beam shape after collimation. Using the THz pulse time-domain holography method [3] one could obtain the THz field distribution in each spatial coordinate, which provided the polarization distribution pictures. The measurement area of the THz signal at every point was 5 mm in diameter (Fig.…”

“…Terahertz radiation (THz) is widely applied in biological diagnostics systems [1], chemistry [2], holography [3][4][5] and imaging [6,7]. There are three main types of THz generation methods with femtosecond pulse pumping: nonlinear optical rectification [8], generation from the surface of a semiconductor layer based on the Dember effect (or by means of a photoconductive antenna) and femtosecond-laser-beam filamentation [9,10].…”

Glycerol dehydration of native and diabetic animal tissues studied by THz-TDS and NMR methods

“…For the wavefront numerical propagation study we used THz Pulse Time Domain Holography method (THz PTDH) [51,52]. This technique allows the calculation of the THz complex field propagation to an arbitrary plane by the angular spectrum (AS) and Rayleigh-Sommerfeld convolution (RSC) method [53].…”

Review of GaN-based devices for terahertz operation

“…16 These capabilities of THz-TDS systems are utilized in authentication, [17][18][19] nondestructive inspection of composite materials, [20][21][22][23][24][25][26][27][28] threedimensional imaging, [29][30][31][32] metrology and quality control of industrial products, [33][34][35][36][37] detection of concealed weapons, [38][39][40][41][42][43][44][45] art investigations, 46,47 tomography, [48][49][50][51][52] biomedical diagnosis, [53][54][55][56] material characterization, [57][58][59][60][61][62] thickness measurement, 63,64 and holography. [65]…”