Thursday, August 17, 2017

Abstract-Optical and THz Evaluation of Components for Gas Sensing Spectroscopy in Hazardous Environments


Dan Sporea, Laura Mihai, Adelina Sporea, Daniel Ighigeanu, Daniel Neguţ

https://link.springer.com/chapter/10.1007/978-94-024-1093-8_9

In this paper, we report for the first time a comparative investigation on gamma and electron beam irradiation effects on some mid-IR materials (ZnSe, CaF2, BaF2, and sapphire) used as components in trace gas detection systems, in the 15–100 THz spectral range. Optical transmittance/reflectance measurements were performed from UV to far IR (0.2–23 μm) on both non-irradiated and irradiated samples. These investigations were complemented by THz spectroscopy and imaging tests run under the same conditions.

Abstract-Effect of acceptor concentration on the dark current characteristics for GaAs-based blocked impurity band (BIB) terahertz detectors



Xiaodong Wang,   Yulu Chen,   Bingbing Wang,   Xiaoyao Chen,   Fangmin Guo, Ming Pan,

http://ieeexplore.ieee.org/document/8009988/

In this paper, the structural model and the physical model of GaAs-based BIB THz detectors are constructed by means of numerical simulation. The effect of acceptor concentration on the dark current characteristics is investigated. Additionally, the optimal acceptor concentration corresponding to the maximum detectivity has been discussed from the application point of view


Abstract-Energy loss of terahertz electromagnetic waves by nano-sized connections in near-self-complementary metallic checkerboard patterns



Keisuke TakanoYoku TanakaGabriel MorenoAbdallah ChahadihAbbas GhaddarXiang-Lei HanFrançois VauretteYosuke NakataFumiaki MiyamaruMakoto NakajimaMasanori Hangyo,Tahsin Akalin

https://arxiv.org/abs/1708.03107

The design of a self-complementary metallic checkerboard pattern achieves broadband, dispersion-less, and maximized absorption, concentrating in the deep subwavelength resistive connections between squares, without any theoretical limitation on the energy absorbing area. Here, we experimentally and numerically investigate the electromagnetic response in the limit of extremely small connections. We show that finite conductivity and randomness in a near-self-complementary checkerboard pattern plays a crucial role in producing a frequency-independent energy loss in the terahertz frequency region. Here metals behave like an almost perfect conductor. When the checkerboard pattern approaches the perfect self-complementary pattern, the perfect conductor approximation spontaneously breaks down, owing to the finite conductivity at the nano- scale connection, leading to broadband absorption. It is also shown that the random connections between metallic squares also lead to broadband and maximized energy loss through scattering loss, similar to finite conductivity.

Wednesday, August 16, 2017

Email from Irl Duling Director of Terahertz Business Development- F-35 news and other.



(My note: Out of the blue I just got this email from Dr. Irl Duling Director of Terahertz Business Development at Picometrix, which he gave me permission to share with readers here. Thank you Dr. Duling for the update!).

Hi Randy,

Steve asked me to contact you.


As you have probably heard there are big tidal shifts here as:

1. API was purchased by Luna
2. Rick Kurtz left the company
3. Rob Risser took over and then passed away
4. Luna sold the HSOR business (and the Picometrix name) to MACOM

We are currently working on settling the THz portion of the company within Luna without the rest of what was Picometrix.

In spite of all that turmoil we have been making good progress on the THz product line.
All sales volumes are on an upward trajectory.

I hope that as things settle you will start seeing a steady flow of information, since some of the impediments to that have now been removed.

Concerning our work with the F-35, we have continued working with Lockheed Martin (LM) and Northrop Grumman Corp (NGC).

With NGC we have been measuring the external coating as it is applied in the paint booth.  That required a CID1 certification, which we have obtained (for the measurement head).

At LM, our SPG (Single Point Gauge), which is a handheld THz measurement tool is being used on the production floor to verify the coating thickness as the plane is being assembled, and before it goes into final test.

The SPG is also being tested on other airframes.

The third application that is being developed is our LSG (Line Scan Gauge) which runs a Step-Chek software package to measure the step and gap between panels as the plane is assembled.  We have delivered the first items to LM and they are going through the testing process.  The LSG is also being used by NASA on the Orion spacecraft.

As with any government program, the pace is slow, but steady, and we expect to see increased traction in the coming years.

Best regards,

Irl

Irl Duling, PhD
Director of Terahertz Business Development
Picometrix, a division of Luna Innovations
2925 Boardwalk
Ann Arbor, MI 48104


Abstract-Testing of Sub-THz Properties of Bioliquids Using WGM Resonator with Microfluidic Channel



I. A. Protsenko, A. A. Barannik, A. I. Gubin, N. T. Cherpak, S. A. Vitusevich

https://link.springer.com/chapter/10.1007/978-94-024-1093-8_8

In the present work, the measurement cell for investigation of small-volume liquids in sub-THz range is proposed. The proposed measurement cell is based on the whispering-gallery mode quartz resonator covered with the plastic layer comprising the microfluidic channel and allows obtaining the complex permittivity of the liquid filling the microfluidic channel. Investigation of the resonator structure was carried out experimentally and using the numerical model of the structure. It is shown that the resonator structure can be used as a measurement cell with additional calibration procedure.