Terahertz Microscope Based on Solid Immersion Effect for Imaging of Biological Tissues

We propose a new method of terahertz microscopy for imaging of biological tissues with a subwavelength spatial resolution. It makes it possible to surmount the Abbe diffraction limit and ensures a subwavelength resolution due to the solid immersion effect, i.e., due to decreasing dimensions of the electromagnetic beam caustic as the beam is focused in free space at a small distance (smaller than the wavelength) behind a medium with a high refractive index. An experimental setup that realizes the proposed method is developed. It uses a backward-wave oscillator and a Golay cell as a source and a detector of the terahertz radiation, respectively. In this setup, the radiation is focused behind a silicon hemisphere to realize the solid immersion effect. A record-high spatial resolution of 0.15λ is demonstrated experimentally for optical systems based on the solid immersion effect (the measurements have been performed at a wavelength of λ = 500 μm using a metal–air interface as a test object). Microscopy based on the solid immersion effect does not imply using diaphragms or near-field probes of other types for achieving the subwavelength spatial resolution, and, correspondingly eliminates energy losses associated with these elements. The proposed method has been applied for imaging of soft biological tissues, which has made it possible to demonstrate its potential for the use in biology and medicine.

[1]  A. A. Konovko,et al.  Terahertz biophotonics as a tool for studies of dielectric and spectral properties of biological tissues and liquids , 2018, Progress in Quantum Electronics.

[2]  Anil T. Ahuja,et al.  THz in vivo measurements: the effects of pressure on skin reflectivity. , 2018, Biomedical optics express.

[3]  C. Choy,et al.  Dielectric properties and abnormal C-V characteristics of Ba[sub 0.5]Sr[sub 0.5]TiO₃-Bi[sub 1.5]ZnNb[sub 1.5]O[sub 7] composite thin films grown on MgO (001) substrates by pulsed laser deposition , 2006 .

[4]  Yusuf Leblebici,et al.  High spatial resolution subsurface thermal emission microscopy , 2004 .

[5]  Rakesh Patel,et al.  Imaging of ex vivo nonmelanoma skin cancers in the optical and terahertz spectral regions Optical and Terahertz skin cancers imaging , 2014, Journal of biophotonics.

[6]  J. Aizpurua,et al.  Terahertz near-field nanoscopy of mobile carriers in single semiconductor nanodevices. , 2008, Nano letters.

[7]  Dmitry Ponomarev,et al.  Terahertz solid immersion microscopy for sub-wavelength-resolution imaging of biological objects and tissues , 2018, Saratov Fall Meeting.

[8]  A. Lewis,et al.  Applying solid immersion near-field optics to Raman analysis of strained silicon thin films , 2006 .

[9]  Lukas Novotny,et al.  Enhanced reflectivity contrast in confocal solid immersion lens microscopy , 2000 .

[10]  Martin Dressel,et al.  THz-micro-spectroscopy with backward-wave oscillators , 2006 .

[11]  M. Nuss,et al.  Imaging with terahertz waves. , 1995, Optics letters.

[12]  R. Kersting,et al.  Terahertz imaging with nanometer resolution , 2003 .

[13]  Tadao Nagatsuma,et al.  Three-dimensional direct observation of Gouy phase shift in a terajet produced by a dielectric cuboid , 2016 .

[14]  Zengbo Wang,et al.  Production of photonic nanojets by using pupil-masked 3D dielectric cuboid , 2017 .

[15]  Zengbo Wang,et al.  Intensity‐Enhanced Apodization Effect on an Axially Illuminated Circular‐Column Particle‐Lens , 2018 .

[16]  I. V. Minin,et al.  Experimental observation of a photonic hook , 2018, Applied Physics Letters.

[17]  Bruce D. Terris,et al.  Near‐field optical data storage using a solid immersion lens , 1994 .

[18]  O. E. Porodinkov,et al.  BWO Generators for Terahertz Dielectric Measurements , 2013, IEEE Transactions on Terahertz Science and Technology.

[19]  G. Kino,et al.  Solid immersion microscope , 1990 .

[20]  A. Loidl,et al.  Focusing of millimeter-wave radiation beyond the Abbe barrier , 2003 .

[21]  V Krozer,et al.  Terahertz Imaging Systems With Aperture Synthesis Techniques , 2010, IEEE Transactions on Microwave Theory and Techniques.

[22]  Yan Zhang,et al.  Terahertz Digital Holography , 2008 .

[23]  B. Hecht,et al.  Principles of nano-optics , 2006 .

[24]  Zengbo Wang,et al.  Photonic hook: a new curved light beam. , 2017, Optics letters.

[25]  Igor V. Minin,et al.  Photonic Hook Plasmons: A New Curved Surface Wave , 2018, Annalen der Physik.

[26]  V. Tuchin.  Tissue Optics: Light Scattering Methods and Instruments for Medical Diagnosis , 2000 .

[27]  Kathirvel Nallappan,et al.  Toward real-time terahertz imaging , 2018, Advances in Optics and Photonics.

[28]  Stanislav O. Yurchenko,et al.  Terahertz spectroscopy of pigmentary skin nevi in vivo , 2015 .

[29]  Tadao Nagatsuma,et al.  Enhancement of spatial resolution of terahertz imaging systems based on terajet generation by dielectric cube , 2017 .

[30]  Valery V. Tuchin,et al.  In vitro terahertz spectroscopy of gelatin-embedded human brain tumors: a pilot study , 2018, Saratov Fall Meeting.

[31]  K. Hirota,et al.  Roles of propagating and evanescent waves in solid immersion lens systems. , 1999, Applied optics.

[32]  Zengbo Wang,et al.  Refractive index less than two: photonic nanojets yesterday, today and tomorrow [Invited] , 2017 .

[33]  E. Pickwell‐MacPherson,et al.  Terahertz pulsed spectroscopy of freshly excised human breast cancer. , 2009, Optics express.

[34]  V. Karasik,et al.  Sapphire Photonic Crystal Waveguides for Terahertz Sensing in Aggressive Environments , 2018, Advanced Optical Materials.

[35]  F. Keilmann,et al.  All-electronic terahertz nanoscopy , 2018 .

[36]  G. Kino,et al.  Refraction contrast imaging with a scanning microlens , 2001 .

[37]  I. V. Minin,et al.  A potential of terahertz solid immersion microscopy for visualizing sub-wavelength-scale tissue spheroids , 2018, Photonics Europe.

[38]  Zengbo Wang,et al.  Subwavelength Imaging with Dielectric Metamaterial Solid-Immersion Lens , 2015, 1511.01152.

[39]  Akira Ishimaru,et al.  Electromagnetic Wave Propagation, Radiation, and Scattering: From Fundamentals to Applications , 2017 .

[40]  Zengbo Wang,et al.  A Millimetre-Wave Cuboid Solid Immersion Lens with Intensity-Enhanced Amplitude Mask Apodization , 2018 .

[41]  Harry Nyquist.  Certain Topics in Telegraph Transmission Theory , 1928 .

[42]  M. Skorobogatiy,et al.  Label-free bacteria detection using evanescent mode of a suspended core terahertz fiber , 2012, 2012 Conference on Lasers and Electro-Optics (CLEO).

[43]  Emma Pickwell-MacPherson,et al.  Gelatin embedding: a novel way to preserve biological samples for terahertz imaging and spectroscopy , 2015, Physics in medicine and biology.

[44]  F. H. Köklü,et al.  Widefield subsurface microscopy of integrated circuits. , 2008, Optics express.

[45]  Janez Trontelj,et al.  A Microbolometer System for Radiation Detection in the THz Frequency Range with a Resonating Cavity Fabricated in the CMOS Technology. , 2017, Recent patents on nanotechnology.

[46]  E. Linfield,et al.  Terahertz pulse imaging of ex vivo basal cell carcinoma. , 2003, The Journal of investigative dermatology.

[47]  G. S. Kolontaeva,et al.  Reflection-mode continuous-wave 0.15λ-resolution terahertz solid immersion microscopy of soft biological tissues , 2018, Applied Physics Letters.

[48]  E. Pickwell‐MacPherson,et al.  Simulation of Terahertz Pulse Propagation in Biological Systems , 2004 .

[49]  G. Kino,et al.  Near-field infrared imaging with a microfabricated solid immersion lens , 2000 .

[50]  Igor V. Minin,et al.  Terahertz artificial dielectric cuboid lens on substrate for super-resolution images , 2017 .

[51]  H. A. Zahl,et al.  Pneumatic heat detector. , 1946, The Review of scientific instruments.

[52]  Ke Yang,et al.  Biomedical Applications of Terahertz Spectroscopy and Imaging. , 2016, Trends in biotechnology.

[53]  Zengbo Wang,et al.  Three-dimensional all-dielectric metamaterial solid immersion lens for subwavelength imaging at visible frequencies , 2015, Science Advances.

[54]  V V Tuchin,et al.  Light propagation in tissues with controlled optical properties , 1996, European Conference on Biomedical Optics.

[55]  Kirill I. Zaytsev,et al.  Solid immersion terahertz imaging with sub-wavelength resolution , 2017 .