Lenses for terahertz applications: Development of new materials and production processes

Kocic, Nikola; Wichmann, Matthias; Hochrein, Thomas; Heidemeyer, Peter; Kretschmer, Karsten; Radovanovic, I.; Mondol, Abdullah Saif; Koch, Martin; Bastian, Martin

doi:10.1063/1.4873811

Cited by 3 publications

(2 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…56 Kocic et al demonstrated THPN lenses made with a high refractive index of 3.02 through extrusion after mixing commercial TiO 2 and Al 2 O 3 NPs with each matrix including polypropylene (PP), high-density polyethylene (HDPE), and cycloolefin polymer (COP). 57 He et al prepared an acrylate-based microlens array by incorporating ZrO 2 and SiO 2 sol into a photoresist. 58 A holographic recording medium (HRM), one of effective data storage methods, is based on optical interferences between light coming from multiple light sources.…”

Section: Applications Of Zro 2 Thpn As Transparent Advanced Optical M...mentioning

confidence: 99%

Zirconia nanocomposites and their applications as transparent advanced optical materials with high refractive index

Lee

Cho

Yoon

2023

Bulletin Korean Chem Soc

View full text Add to dashboard Cite

Polymer nanocomposites, prepared by incorporating functional nanoparticles (NPs) into a polymer matrix, have advantages of utilizing functionalities of polymers and NPs. Among them, transparent high-refractive-index polymer nanocomposites (THPNs), prepared by incorporating highly refractive NPs into polymer matrices, are advantageous for effectively manipulating light. This review focuses on the introduction of fabrication of THPN prepared by incorporating inorganic-oxide NPs, especially zirconia (ZrO 2 ), and its characteristics as an optical material. ZrO 2 NPs have a high refractive index and high transmittance in visible light regions with high and narrow optical bandgap energy. Since ZrO 2 NPs are harmless to humans and physically and chemically stable, they are suitable for applications of advanced optical materials for display and energy devices. Various fabrication methods of THPN with ZrO 2 NPs and surface modifications of ZrO 2 NPs to prevent agglomeration are introduced. Principles and specific applications, which THPN could work with and for, are introduced as well.

show abstract

Section: Applications Of Zro 2 Thpn As Transparent Advanced Optical M...mentioning

confidence: 99%

Zirconia nanocomposites and their applications as transparent advanced optical materials with high refractive index

Lee

Cho

Yoon

2023

Bulletin Korean Chem Soc

View full text Add to dashboard Cite

show abstract

“…Conventional THz imaging systems based on CW and pulsed sources have been implemented with refractive optics (transmission lenses). They were constructed of materials that were transparent against THz waves—for example, high resistivity float zone silicon (HRFZ-Si), quartz, fused silica (FS), and polymers [ 43 ]. However, there is noticeable attenuation in the high-frequency range larger than 1 THz.…”

Section: Introductionmentioning

confidence: 99%

High-Speed THz Time-of-Flight Imaging with Reflective Optics

Yoo

Kim²,

Ahn

2023

Sensors

View full text Add to dashboard Cite

In this study, we develop a 3D THz time-of-flight (TOF) imaging technique by using reflective optics to preserve the high-frequency components from a THz antenna. We use an Fe:InGaAs/InAlAs emitter containing relatively high-frequency components. THz-TOF imaging with asynchronous optical sampling (ASOPS) enables the rapid scanning of 100 Hz/scan with a time delay span of 100 ps. We characterize the transverse resolution using knife edge tests for a focal length of 5; the Rayleigh resolution has been measured at 1.0 mm at the focal plane. Conversely, the longitudinal resolution is determined by the temporal pulse width, confirmed with various gap structures enclosed by a quartz substrate. The phase analysis reveals that reflected waves from the top interface exhibit a phase shift when the gap is filled by high-indexed materials such as water but shows in-phase behavior when it is filled with air and low-indexed material. Our imaging tool was effective for inspecting the packaged chip with high lateral and longitudinal resolution. Importantly, the phase information in 2D and 3D images is shown to be a powerful tool in identifying the defect—in particular, delamination in the chip—which tends to be detrimental to the packaged chip’s stability.

show abstract

Fabrication and characterization of a composite TiO₂-polypropylene high-refractive-index solid immersion lens for super-resolution THz imaging

Chapdelaine¹,

Nallappan²,

Cao³

et al. 2022

Opt. Mater. Express

View full text Add to dashboard Cite

Terahertz (THz) near-field imaging is attracting a lot of attention for its potential applications in medical diagnosis and material characterization. However, the spatial resolution of the recorded THz image was mainly limited by the diffraction limit of the commonly used lens- and mirror-based THz optical systems. Alternatively, a solid immersion lens (SIL) can be a promising approach for achieving super-resolution imaging as it reduces the spot size of the focused THz beam by a factor of 1/n, where n is the refractive index (RI) of the lens material. In this work, we present the design and fabrication of hemispherical THz SIL using powder mixes of titanium dioxide (TiO2) and polypropylene (PP) whose RIs are ≈10 and ≈1.51, respectively, at 1.0 THz. In particular, we present two different lens fabrication strategies that are simple and cost-effective solutions. The first strategy uses pressing the TiO2 powder with a PP powder at the Vicat temperature of PP while controlling the concentration of TiO2 and the resultant lens porosity. The second design consists in pressing the TiO2 powder in a hollow hemisphere that is 3D printed using PP. The fabricated lenses are then characterized physically and optically, and their RIs are compared to the theoretical estimates using the Bruggeman model of the effective media. From the experimental measurements of the proposed SIL, a resolution limit as low as 0.2λ was achieved at 0.09 THz (λ ≈ 3.3 mm), which is comparable to the best resolutions reported in the literature.

show abstract

Lenses for terahertz applications: Development of new materials and production processes

Cited by 3 publications

References 0 publications

Zirconia nanocomposites and their applications as transparent advanced optical materials with high refractive index

Zirconia nanocomposites and their applications as transparent advanced optical materials with high refractive index

High-Speed THz Time-of-Flight Imaging with Reflective Optics

Fabrication and characterization of a composite TiO₂-polypropylene high-refractive-index solid immersion lens for super-resolution THz imaging

Contact Info

Product

Resources

About

Lenses for terahertz applications: Development of new materials and production processes

Cited by 3 publications

References 0 publications

Zirconia nanocomposites and their applications as transparent advanced optical materials with high refractive index

Zirconia nanocomposites and their applications as transparent advanced optical materials with high refractive index

High-Speed THz Time-of-Flight Imaging with Reflective Optics

Fabrication and characterization of a composite TiO2-polypropylene high-refractive-index solid immersion lens for super-resolution THz imaging

Contact Info

Product

Resources

About

Fabrication and characterization of a composite TiO₂-polypropylene high-refractive-index solid immersion lens for super-resolution THz imaging