Abstract-Sensitive characterizations of natural dolomite by terahertz time-domain spectroscopy

Sibo Hao, Haochong Huang,  Yuanyuan Ma,  Zili Zhang,  Zhiyuan Zheng,



https://www.sciencedirect.com/science/article/abs/pii/S0030401819307990

The pyrolysis and the porosity of natural dolomite are investigated by terahertz time-domain spectroscopy for primary quality control in industry. From terahertz spectra, the transformation of natural dolomite modified by calcination can be clearly differentiated. Based on such results, the thermal active dolomite is studied on adsorbing copper ions in water at first glance. Also, the terahertz maps highlight the subtle variations of the nominal porosity existing in dolomite. In particular, the refractive index and absorption coefficients evidence the variation of mineral properties within natural dolomite. Compared with traditional methods, terahertz time-domain spectroscopy is thus of great significances to gain a non-destructive and contact-free understanding of natural minerals, even in geological studies and environmental industries.

Abstract-Insights into the water status in hydrous minerals using terahertz time-domain spectroscopy

Yuanyuan Ma, Haochong Huang, Sibo Hao, Kunfeng Qiu, Hua Gao, Lu Gao, Weichong Tang, Zili Zhang, Zhiyuan Zheng


https://www.nature.com/articles/s41598-019-45739-2

The determinations of water status incorporated in hydrous minerals are of considerable significances in geoscience fields. Coincidentally, the aqueous sensitivity of terahertz radiation has motivated numerous explorations in several cross-domain applications. Terahertz time-domain spectroscopy is employed as a major probing technique coupling of traditional detecting methods to uncover the mask of water status in copper sulfate pentahydrate as well as mineral quartz in this article. Based on the quantitative identification of water status in copper sulfate pentahydrate, the water incorporated in mineral quartz is verified qualitatively. Notable differences of optical constants originating from the water content are obtained for copper sulfate pentahydrate and mineral quartz. These present works indicate that terahertz technology can be considered as a promising method to satisfy the ever-increasing requirements in hydrous mineral analyses.

Abstract-Methods for registering and calibrating in vivo terahertz images of cutaneous burn wounds

Priyamvada Tewari, James Garritano, Neha Bajwa, Shijun Sung, Haochong Huang, Dayong Wang, Warren Grundfest, Daniel B. Ennis, Dan Ruan, Elliott Brown, Erik Dutson, Michael C. Fishbein, and Zachary Taylor

Fig. 1 Burn zones organize as concentric like shells in the depth are hypothesized to appear as projections of the shells on the surface. Skin layers denoted A, B, C and damage zones denoted 1, 2, 3, 4. (a) Cross-sectional view: damage from superficial thickness wounds are limited primarily to the stratum corneum and epidermis, partial thickness burn wounds extend into the epidermis, and full thickness wounds extend into deep dermis. (b) Isometric view providing orientation between (a) and (c). (c) Top down view: The damage zones, and thus variations in surface TWC should present as regions concentric with the center.

https://www.osapublishing.org/boe/abstract.cfm?uri=boe-10-1-322

A method to register THz and visible images of cutaneous burn wounds and to calibrate THz image data is presented. Images of partial and full thickness burn wounds in 9 rats were collected over 435 mins. = 7.25 hours following burn induction. A two-step process was developed to reference the unknown structure of THz imaging contrast to the known structure and the features present in visible images of the injury. This process enabled the demarcation of a wound center for each THz image, independent of THz contrast. Threshold based segmentation enabled the automated identification of air (0% reflectivity), brass (100% reflectivity), and abdomen regions within the registered THz images. Pixel populations, defined by the segmentations, informed unsupervised image calibration and contrast warping for display. The registered images revealed that the largest variation in THz tissue reflectivity occurred superior to the contact region at ~0.13%/min. Conversely the contact region showed demonstrated an ~6.5-fold decrease at ~0.02%/min. Exploration of occlusion effects suggests that window contact may affect the measured edematous response.

© 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Abstract-Synthetic aperture in terahertz in-line digital holography for resolution enhancement

Haochong Huang, Lu Rong, Dayong Wang, Weihua Li, Qinghua Deng, Bin Li, Yunxin Wang, Zhiqiang Zhan, Xuemin Wang, and Weidong Wu

https://www.osapublishing.org/ao/abstract.cfm?uri=ao-55-3-A43&origin=search

Terahertz digital holography is a combination of terahertz technology and digital holography. In digital holography, the imaging resolution is the key parameter in determining the detailed quality of a reconstructed wavefront. In this paper, the synthetic aperture method is used in terahertz digital holography and the in-line arrangement is built to perform the detection. The resolved capability of previous terahertz digital holographic systems restricts this technique to meet the requirement of practical detection. In contrast, the experimental resolved power of the present method can reach 125 μm, which is the best resolution of terahertz digital holography to date. Furthermore, the basic detection of a biological specimen is conducted to show the practical application. In all, the results of the proposed method demonstrate the enhancement of experimental imaging resolution and that the amplitude and phase distributions of the fine structure of samples can be reconstructed by using terahertz digital holography.

© 2015 Optical Society of America

Abstract-Terahertz in-line digital holographic multiplane imaging method

Haochong Huang, Dayong Wang, Lu Rong, Yunxin Wang

Beijing Univ. of Technology (China)

Weihua Li

China Academy of Engineering Physics (China)

http://proceedings.spiedigitallibrary.org/proceeding.aspx?articleid=2628165

Terahertz waves of which frequency spans from 0.1 to 10 THz bridge the gap between the infrared spectrum and microwaves. Owing to the special features of terahertz wave, such as penetrability and non-ionizing, terahertz imaging technique is a very significant and important method for inspections and detections. Digital holography can reconstruct the amplitude and phase distributions of a sample without scanning and it already has many successful applications in the area of visible and infrared light. The terahertz in-line digital holographic multi-plane imaging system which is presented in this paper is the combination of a continuous-wave terahertz source and the in-line scheme of digital holography. In order to observe a three dimensional (3D) shape sample only a portion of which appears in good focus, the autofocusing algorithm is brought to the data process. The synthetic aperture method is also applied to provide the high resolution imaging effect in the terahertz waveband. Both intrinsic twin images and defocused objective images confuse the quality of the image in an individual reconstructed plane. In order to solve this issue, phase retrieval iteration algorithm is used for the reconstruction. In addition, the reconstructed amplitude image in each plane multiplies the mask of which the threshold depends on the values of the autofocusing curve. A sample with simple artificial structure is observed which verifies that the present method is an authentic tool to acquire the multi-plane information of a target in terahertz waves. It can expect a wide application in terahertz defect detecting, terahertz medical inspection and other important areas in the future. 

© (2017) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

Abstract-Biological Imaging Application by Using Continuous-wave Terahertz In-line Digital Holography

Haochong Huang, Dayong Wang, Lu Rong, Bin Li, and Yunxin Wang

https://www.osapublishing.org/abstract.cfm?uri=OMP-2017-JTu4A.22

Continuous-wave terahertz in-line digital holography is a novel quantitative phase-contrast imaging approach. The exprimental verification confirms that the present method is an high resolution biological detection technique in terahertz wave.

© 2017 OSA

Abstract-Terahertz in-line digital holography of human hepatocellular carcinoma tissue

http://www.nature.com/srep/2015/150213/srep08445/full/srep08445.html

• Lu Rong,
• Tatiana Latychevskaia,
• Chunhai Chen,
• Dayong Wang,
• Zhengping Yu,
• Xun Zhou,
• Zeyu Li,
• Haochong Huang,
• Yunxin Wang
• & Zhou Zhou

• Affiliations
• Contributions
• Corresponding authors

Scientific Reports

 

5,

 

Article number:

 

8445

 

doi:10.1038/srep08445

Received

 

16 July 2014 

Accepted

 

20 January 2015 

Published

 

13 February 2015

Terahertz waves provide a better contrast in imaging soft biomedical tissues than X-rays, and unlike X-rays, they cause no ionisation damage, making them a good option for biomedical imaging. Terahertz absorption imaging has conventionally been used for cancer diagnosis. However, the absorption properties of a cancerous sample are influenced by two opposing factors: an increase in absorption due to a higher degree of hydration and a decrease in absorption due to structural changes. It is therefore difficult to diagnose cancer from an absorption image. Phase imaging can thus be critical for diagnostics. We demonstrate imaging of the absorption and phase-shift distributions of 3.2 mm × 2.3 mm × 30-μm-thick human hepatocellular carcinoma tissue by continuous-wave terahertz digital in-line holography. The acquisition time of a few seconds for a single in-line hologram is much shorter than that of other terahertz diagnostic techniques, and future detectors will allow acquisition of meaningful holograms without sample dehydration. The resolution of the reconstructions was enhanced by sub-pixel shifting and extrapolation. Another advantage of this technique is its relaxed minimal sample size limitation. The fibrosis indicated in the phase distribution demonstrates the potential of terahertz holographic imaging to obtain a more objective, early diagnosis of cancer.

Abstract-Terahertz in-line digital holography of dragonfly hindwing: amplitude and phase reconstruction at enhanced resolution by extrapolation

Lu Rong, Tatiana Latychevskaia, Dayong Wang, Xun Zhou, Haochong Huang, Zeyu Li, and Yunxin Wang  »View Author Affiliations http://8.18.37.105/oe/abstract.cfm?uri=oe-22-14-17236

Optics Express, Vol. 22, Issue 14, pp. 17236-17245 (2014)
http://dx.doi.org/10.1364/OE.22.017236

We report here on terahertz (THz) digital holography on a biological specimen. A continuous-wave (CW) THz in-line holographic setup was built based on a 2.52 THz CO₂ pumped THz laser and a pyroelectric array detector. We introduced novel statistical method of obtaining true intensity values for the pyroelectric array detector’s pixels. Absorption and phase-shifting images of a dragonfly’s hindwing were reconstructed simultaneously from single in-line hologram. Furthermore, we applied phase retrieval routines to eliminate twin image and enhanced the resolution of the reconstructions by hologram extrapolation beyond the detector area. The finest observed features are 35 μm width cross veins.

© 2014 Optical Society of America

Abstract-Terahertz in-line digital holography of dragonfly hindwing: amplitude and phase reconstruction at enhanced resolution by extrapolation

http://www.opticsinfobase.org/oe/abstract.cfm?uri=oe-22-14-17236

Lu Rong, Tatiana Latychevskaia, Dayong Wang, Xun Zhou, Haochong Huang, Zeyu Li, and Yunxin Wang  »View Author Affiliations

Optics Express, Vol. 22, Issue 14, pp. 17236-17245 (2014)
http://dx.doi.org/10.1364/OE.22.017236

We report here on terahertz (THz) digital holography on a biological specimen. A continuous-wave (CW) THz in-line holographic setup was built based on a 2.52 THz CO₂ pumped THz laser and a pyroelectric array detector. We introduced novel statistical method of obtaining true intensity values for the pyroelectric array detector’s pixels. Absorption and phase-shifting images of a dragonfly’s hindwing were reconstructed simultaneously from single in-line hologram. Furthermore, we applied phase retrieval routines to eliminate twin image and enhanced the resolution of the reconstructions by hologram extrapolation beyond the detector area. The finest observed features are 35 μm width cross veins.

© 2014 Optical Society of America