Near- field and polarization sensitive spectroscopic THz imaging technology for medical needs

Terahertz (THz) imaging is assumed to be powerful tool in a large variety of applications starting form security [M. Kato, S. R. Tripathi, K. Murate, K. Imayama, and K. Kawase, Opt. Express 24, 6425 (2016), U. Puc, A. Abina, M. Rutar, A. Zidanšek, A. Jeglič, and G. Valušis, Appl. Opt. 54, 4495 (2015)], food control [A. A. Gowen, C. O’sullivan, and C. P. O’Donnell, Trends Food Sci. Technol. 25, 40 (2012)], package inspection [L. Minkevičius, V. Tamošiunas, I. Kašalynas, D. Seliuta, G. Valušis, A. Lisauskas, S. Boppel, H. G. Roskos, and K. Köhler, Appl. Phys. Lett. 99, 131101 (2011)], as well as biomedicine diagnostics [I.Kašalynas, R.Venckevičius, L.Minkevičius, A.Sešek, F.Wahaia, V. Tamošiūnas, B. Voisiat, D. Seliuta, G. Valušis, A. Švigelj, and J. Trontelj, Sensors 16, 432 (2016); B. C. Ų. Truong, A. J. Fitzgerald, S. Fan, and V. P. Wallace, Biomed. Opt. Express 9, 1334 (2018)].

Strong absorption of THz radiation by water can serve as base to indicate even small changes in an illness affected tissue, however, due to large absorption value, it is definitely not enough to provide enough arguments for detailed informative conclusions. – it is of particular importance to reveal changes induced by structural defects or thier variation from changes because of the pure water absorption.

The aim of the PhD thesis is threefold:
  • To develop spectroscopic polarization sensitive THz imaging set-up for medical applications: the linearly polarized THz light used to illuminate object can be recorded in imaging in a perpendicular direction with respect to illumination polarization enabling thus to resolved structural –determined changes from that caused by change of water absorption;
  • To develop spectroscopic polarization sensitive THz imaging set-up for medical applications in near-field using metamaterials;
  • To demonstrate distinctive features of both imaging set-ups in comparison to conventional THz imaging in medical applications investigating skin cancer and melanoma affected tissues.
Department of Optoelectronics has all necessary experimental techniųues and eųuipment needed to reach successfully the aims of the PhD studies.

Two Fourier spectrometers and time domain THz spectroscopy set-up, continuous wave spectroscopic THz technology based on electronic sources operating in subTHz range and optically-pumped THz laser within 0.87 THz up to 5.6 THz are available in the laboratories.

In addition, compact silicon diffractive optics with high numerical aperture are developed, metamaterials design and their research are evolving intensively -- these set-ups are already widely employed in application of THz spectroscopy and imaging for medical aims.

Cooperation is planned with the National Center of Pathology and National Cancer Institute at Vilnius.

Recently, application entitled „ Nanoparticle-enabled Endoscopic Terahertz Molecular Imaging for the diagnosis of early gastro-intestinal neoplasia“ was submitted to EuroNanoMed 3 programme together with collegues from Romania and Spain.
For more information, please contact the theme supervisor G. Valušis.