Fiber MOPA based tunable source for terahertz spectroscopy

Malinowski, A.; Lin, Di; Alam, Shaif-ul; Zhang, Z.; Ibsen, M.; Young, Joshua T.; Wright, Pearce; Ozanyan, K.B.; Stringer, Maurice; Miles, R.E.; Richardson, David J.

doi:10.7452/lapl.201110143

Cited by 7 publications

(7 citation statements)

References 25 publications

(22 reference statements)

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“…A narrow-bandwidth terahertz spectrometer with a tuning range limited to 0.4 THz from a central wavelength has been previously demonstrated in our group by Malinowski et al 1 . In this work we demonstrate our progress towards a significantly upgraded system tunable over a range in excess of 2.0 THz (Fig.1).…”

Section: Introductionmentioning

confidence: 89%

“…DFG of THz radiation can be achieved by passing both beams through the GaP crystal in either a collinear or (as in our case) in a non-collinear phase-matched configuration 1 . The tunable beam passes through the GaP perpendicular to the crystal face whilst the fixed wavelength (1060nm) beam is passed through at an angle adjustable by translating the polarizing beam splitter (PBS) which is mounted on a micrometer-driven translation stage.…”

Section: Introductionmentioning

confidence: 99%

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High-resolution broadly-tunable MOPA-based terahertz spectrometer to non-destructively probe and modulate protein electrodynamics

Lewis

Lim

Rowe

et al. 2013

2013 38th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz)

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Ahstract-We report on the development of a high-resolution « GHz at 1.0 THz), broadly-tunable (-0.5 -3.0 THz) fiber MOPA-based terahertz spectrometer system. The flexibility and performance of this system will be demonstrated with gaseous (water vapor) and aqueous (water and solvated protein) samples with a view towards selectively and non-destructively probing functionally significant large-scale protein motions. \. INTRODUCTION AND BACKGROUNDA narrow-bandwidth terahertz spectrometer with a tuning range limited to 0.4 THz from a central wavelength has been previously demonstrated in our group by Malinowski et al. l . In this work we demonstrate our progress towards a significantly upgraded system tunable over a range in excess of 2.0 THz (Fig.1). Since protein folding dynamics take place on the picosecond timescale, vibrational modes tend to lie in the sub-2THz frequency range 2 , 3 . Many recent studies have made extensive use of time-domain THz spectroscopy (TOS) 4 , 5 . The limited spectral resolution of the technique has generated a clear need for high-resolution THz sources, and recent development in this regard has been rapid and widespread 6 , 7 , 8 . Our THz system has a similar dual fiber master oscillator power amplifiers (MOP A) chain design producing two pulsed beams of 2 ns duration at a repetition rate of 0.5 MHz. The maximum peak power per channel is -5 kW (5 W average power). Both MOPA chains are designed to minimize spectral linewidth: one amplifier chain is based on a custom-built distributed feedback (DFB) laser operating at -1060 nm, and the other is based on a Toptica DL pro 1040 tunable external cavity laser with a tuning range of980 -1075 nm. The linewidth before amplification for both chains is of the order of 100 kHz. THz radiation is generated via difference frequency generation (OFG) in a (110) cleaved GaP crystal which is directed through a custom-built fluidic cell mounted in front of a silicon filter and pyroelectric THz detection system. Ahalf-wave plate is located between the main system lens and the GaP crystal to achieve optimum polarization orientation with respect to the crystal orientation.Both MOP A chains exhibit a flat gain response over the entire tuning range, with an optical signal-to-noise ratio (OSNR) of -30 dB (as measured at 0.1 nm resolution) which is particularly flat in the narrow range corresponding to the low frequency (0.5 -1.0 THz) region in the OFG process (Fig. 2).The estimated spectral linewidth of the MOP A output is -500MHz at 1060nm, corresponding to a-I GHz effective linewidth at 1.0 THz with a typical peak THz power of -3 m W.

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Section: Introductionmentioning

confidence: 89%

Section: Introductionmentioning

confidence: 99%

High-resolution broadly-tunable MOPA-based terahertz spectrometer to non-destructively probe and modulate protein electrodynamics

Lewis

Lim

Rowe

et al. 2013

2013 38th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz)

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“…where Φ1 and Φ2 are the respective phase shifts as a function of frequency and c is the speed of light in the sample. The spectra of the attenuation coefficient and the refractive index for the THz working range from 0.2 THz to 2.5 THz, are calculated using (4) and (5) in our case and plotted in Fig. 5.…”

Section: A Styrofoam Attenuation Coefficient and Refractive Indexmentioning

confidence: 99%

“…Applications include spectroscopic identification and imaging, nondestructive evaluation, security inspection and defect detection, among others. Many THz systems require a bulky laser but, in search of practical applications, there has been a growing interest in developing THz portable systems [4,5]. Advances in technology have enabled the development of reduced footprint THz systems based on communications lasers around 1.5 µm.…”

Section: Introductionmentioning

confidence: 99%

Hyperspectral Terahertz Tomography in Amplitude Contrast

Banuelos-Saucedo

Ozanyan

2019

IEEE Sensors J.

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Hyperspectral tomography in THz amplitude contrast is presented using a time-domain spectroscopy system in the spectral range 0.3-2.5 THz. The Fourier transformed signal data is used to reconstruct test objects' cross-sections at multiple frequencies using standard filtered backprojection. The full hyperspectral set of images reconstructed at around 300 adjacent spectral points is used to trace the combined contribution of Beer-Lambert volume attenuation, Fresnel reflection losses and Rayleigh roughness scattering losses, which is in good overall agreement with the experimental results. The image quality for Styrofoam (refractive index around 1.02, attenuation coefficient < 1 mm-1) test objects is best in the range 0.8-2.0 THz depending on the porosity of the material.

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“…With the fast development of material science, precise fabrication and laser technology, terahertz (THz) research has achieved impressive progress in recent years, in terms of both THz source [1] and detectors [2]. Commercialization has started from timedomain spectroscopy (TDS) systems [3], which have been widely used for imaging and sensing applications. Nowadays, there is still a lack of strong THz sources, and few setups can be expected in labs solely.…”

Section: Introductionmentioning

confidence: 99%

An ultra-broadband frequency-domain terahertz measurement system based on frequency conversion via DAST crystal with an optimized phase-matching condition

Feng¹,

Fan²,

Notake³

et al. 2014

Laser Phys. Lett.

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By applying the frequency conversion technique to 4-dimethylamino-N-methyl-4-stilbazolium tosylate crystal, a monochromatic terahertz (THz) measurement system, including both generation and detection, has been developed over quite a broad frequency band, from 1.85 to 30 THz. In the case of frequency upconversion detection of THz waves, for the first time, we used gratings instead of filters to tackle the tough phase-matching conditions for broadband operations. By synchronizing the rotation of two gratings to extract the frequency upconverted signal, the infrared (IR) pumping beam can be tuned freely over 300 nm with decent diffraction efficiency and sufficient isolation between the weak frequency upconversion signal and the strong IR pumping beam to be realized. Such a large tuning range has overcome the limit of commercial filters with a fixed passband, while such a high optical density value has been beyond the limit of commercial tunable filters. Consequently, the proposed frequency domain system gives the largest THz frequency band. Unlike THz time-domain spectroscopy systems in which a fs laser is applied and broadband THz pulses are applied, our system works based on a ns laser and it can function at a single THz frequency with random frequency access ability from pulse to pulse.

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Fiber MOPA based tunable source for terahertz spectroscopy

Abstract: We have developed a terahertz spectrometer based on difference frequency generation of beams from a fiber MOPA. We present some demonstration data on water vapor absorption lines.

Cited by 7 publications

References 25 publications

High-resolution broadly-tunable MOPA-based terahertz spectrometer to non-destructively probe and modulate protein electrodynamics

High-resolution broadly-tunable MOPA-based terahertz spectrometer to non-destructively probe and modulate protein electrodynamics

Hyperspectral Terahertz Tomography in Amplitude Contrast

An ultra-broadband frequency-domain terahertz measurement system based on frequency conversion via DAST crystal with an optimized phase-matching condition

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