Temperature-dependent terahertz spectroscopy and refractive index measurements of aqua-soluble and plastic explosives

Ganesh, D Sharma; Venkatesh, M.; Chaudhary, A.K.

doi:10.1364/ao.57.008743

Cited by 24 publications

(5 citation statements)

References 41 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…THz radiation has potential applications in the fields of spectroscopy, imaging, homeland security and defense, etc. − Therefore, the evaluation of nonlinear optical crystal for THz generation is one of the important aspects of total quality assessment. The 2A5NPDP single crystal grown by the modified SR method was evaluated for the THz generation using 800 nm wavelength of 140 fs at 80 MHz repetition rate obtained from a Ti:sapphire oscillator and efficiency of the generated THz signal was measured using another 800 nm wavelength of 40 fs, at 1 kHz repetition rate obtained from a Ti:sapphire amplifier. − This communication includes the various characterizations performed for 2A5NPDP crystal such as SXRD, PXRD, FTIR, FT-Raman, HRXRD, UV–vis–NIR, TG-DTA, Z -scan, OL, and THz studies.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Linear and Nonlinear Optical Properties of D−π–A Type 2-Amino-5-Nitropyridinium Dihydrogen Phosphate (2A5NPDP) Single Crystal Grown by the Modified Sankaranarayanan–Ramasamy (SR) Method for Terahertz Generation

Vediyappan¹,

Chaudhary

Venkatesh

et al. 2019

Crystal Growth & Design

View full text Add to dashboard Cite

We report the growth process and linear and nonlinear optical characterization of high quality improvised semiorganic 2A5NPDP single crystal using the modified SR method for the first time. The major difficulties for the growth of 2A5NPDP single crystal have been resolved with the aid of a temperature lowering method. After optimization of the growth conditions, a transparent 2A5NPDP single crystal was harvested with a size of 85 mm length and 10 mm diameter over a period of 60 days. The growth rate of the modified SR method grown crystal was found to be 10 times higher than that of the conventional slow evaporation solution technique (SEST) grown crystal. The unit cell parameters of the grown crystal were ascertained by the single crystal X-ray diffraction (SXRD) and powder X-ray diffraction (PXRD) techniques. The high crystalline perfection of the crystal was ascertained by using a high-resolution X-ray diffraction (HRXRD) technique. The presence of multifarious functional groups of the 2A5NPDP crystal were confirmed by Fourier transform infrared (FT-IR) and Fourier transform Raman (FT-Raman) spectral analyses. The thermal property was assessed by the thermogravimetric (TG) and differential thermal analysis (DTA). It shows that the grown crystal withstands temperature up to 175 °C. UV–vis–NIR analysis was used to measure the linear optical property while third-order nonlinear optical properties were ascertained using Z-scan and optical limiting (OL) techniques. The optical limiting threshold of conventional method grown crystal is 5.7 mW/cm2, whereas the modified SR method grown crystal is 4.7 mW/cm2. Low value of limiting threshold indicates that the grown crystal has minimum defects. Finally, 800 nm wavelength of 140 fs at 80 MHz repetition rate obtained from a Ti:sapphire oscillator was used for the terahertz (THz) generation between 0.1 and 2.1 THz range. The efficiency of the generated THz signal was measured using another 800 nm wavelength of 40 fs, at 1 kHz repetition rate obtained from a Ti:sapphire amplifier. The generated THz signal is separated out from unconverted 800 nm using Teflon filters, and power is measured using a pyrometer. The maximum conversion efficiency of generated THz signal is on the order of 0.63 × 10–5%.

show abstract

Section: Introductionmentioning

confidence: 99%

Evaluation of Linear and Nonlinear Optical Properties of D−π–A Type 2-Amino-5-Nitropyridinium Dihydrogen Phosphate (2A5NPDP) Single Crystal Grown by the Modified Sankaranarayanan–Ramasamy (SR) Method for Terahertz Generation

Vediyappan¹,

Chaudhary

Venkatesh

et al. 2019

Crystal Growth & Design

View full text Add to dashboard Cite

show abstract

“…The geometric variation of the MCWMs induced by temperature could thus be ignored. In addition, variations in the temperature-dependent THz refractive index or absorption in plastic and polymer materials have not been observed [ 31 , 32 , 33 ]. The ambient temperature in the MCWM sensing experiments was controlled at 27 ± 0.5 °C.…”

Section: Methodsmentioning

confidence: 99%

Terahertz Plasmonic Sensor Based on Metal–Insulator Composite Woven-Wire Mesh

Chen

You

2022

Biosensors

View full text Add to dashboard Cite

Terahertz (THz) spectroscopy has been proven as an effective detection means for the label-free and nondestructive sensing of biochemical molecules based on their unique roto-vibrational transitions. However, the conventional THz spectroscopic system is unsuitable for minute material sensing due to its far-field detection scheme, low sample amount, and lack of spectral characteristics, leading to low absorption cross-sections and sensitivity. In this study, a 3D plasmonic structure based on a metal-coated woven-wire mesh (MCWM) was experimentally and numerically demonstrated for sensing trace amounts of analytes combined with THz spectroscopy. Dual sharp spectral features were exhibited in the transmission spectrum, originating from the resonant excitation of THz surface electromagnetic modes via the aperture and periodicity of the MCWM unit cell. According to the finite element simulation, an enhanced and localized surface field was formed at THz resonant frequencies and was concentrated at the metal gaps near the periodic corrugations of the MCWM, resulting in enormous resonant dip shifts caused by the tiny variations in membrane thicknesses and refractive indices. Different types and quantities of analytes, including hydrophilic biopolymer (PAA) membrane, nonuniformly distributed microparticles to mimic macro-biomolecules or cells, and electrolyte salts of PBS, were successfully identified by the MCWM sensor with the best thickness and refractive index sensitivities approaching 8.26 GHz/μm and 547 GHz/RIU, respectively. The demonstrated detection limit of thickness and molecular concentration could respectively achieve nanometer and femtomolar scales in PAA macromolecular detection, surpassing the available metallic mesh devices. The MCWM-based sensing platform presents a rapid, inexpensive, and simple analysis method, potentially paving the way for a new generation of label-free microanalysis sensors.

show abstract

“…Utilizing the temporal pro les of the terahertz pulses, valuable information about the material properties, such as absorption, re ection, and transmission, can be extracted out. THz-TDS has a wide range of applications in basic science and applied sciences, such as non-contact characterization, imaging, concealed explosive detection, etc [5][6][7][8][9]. THz-TDS can either be performed in transmission mode or re ection mode.…”

Section: Introductionmentioning

confidence: 99%

Cross-correlation technique for phase error correction in reflection mode terahertz time-domain spectroscopy

Koalla,

Chaudhary

2024

Appl. Opt.

View full text Add to dashboard Cite

The Terahertz time-domain spectroscopy in re ection mode geometry provides valuable surface and subsurface information, making it suitable for layer analysis, coating, and non-destructive testing applications. The exchanging of position of sample and reference introduce a phase error when the position or alignment of the sample is not exactly maintained during measurements. This micrometre order of pitch error ( Δx) between the reference and the sample could lead to introduce inherent error in the phase spectrum of the sample. In the present work, a new novel approach based on cross-correlation technique has been demonstrated to solve the uncertainty in phase and to reveal the hidden characteristic features of the given sample in THz TDS spectroscopy. We illustrated and demonstrated the advantage of our approach by measuring the optical properties of Te on and RDX by correcting misalignment of 31.5 and 41.4 µm range, respectively.

show abstract

Temperature-dependent terahertz spectroscopy and refractive index measurements of aqua-soluble and plastic explosives

Cited by 24 publications

References 41 publications

Evaluation of Linear and Nonlinear Optical Properties of D−π–A Type 2-Amino-5-Nitropyridinium Dihydrogen Phosphate (2A5NPDP) Single Crystal Grown by the Modified Sankaranarayanan–Ramasamy (SR) Method for Terahertz Generation

Evaluation of Linear and Nonlinear Optical Properties of D−π–A Type 2-Amino-5-Nitropyridinium Dihydrogen Phosphate (2A5NPDP) Single Crystal Grown by the Modified Sankaranarayanan–Ramasamy (SR) Method for Terahertz Generation

Terahertz Plasmonic Sensor Based on Metal–Insulator Composite Woven-Wire Mesh

Cross-correlation technique for phase error correction in reflection mode terahertz time-domain spectroscopy

Contact Info

Product

Resources

About