Mechanisms of loss formation in nonlinear optical crystals ZnGeP2 in the terahertz frequency range

Chuchupal, S. V.; Komandin, G. A.; Жукова, Е. С.; Porodinkov, O. E.; Spektor, I. E.; Shakir, Yu. A.; Gribenyukov, A. I.

doi:10.1134/s1063783414070063

Cited by 12 publications

(5 citation statements)

References 20 publications

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“…It should be pointed out that the Drude-Smith model did not allow fitting the experimental data for dark terahertz photoconductivity for our high-resistivity samples with realistic parameters. This could be in accordance with the results of [32,33], where the dominant contribution of combined two-phonon processes (exceeding the Drude-like free-carrier contribution by more than an order of magnitude) to the terahertz dielectric constant in ZnGeP 2 was deduced. The measured dark terahertz dielectric constants are presented in Figure 5.…”

Section: Samplesupporting

confidence: 91%

Electrical Relaxation and Transport Properties of ZnGeP2 and 4H-SiC Crystals Measured with Terahertz Spectroscopy

et al. 2023

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Terahertz photoconductivity and charge carrier recombination dynamics at two-photon (ZnGeP2) and three-photon (4H-SiC) excitation were studied. Thermally annealed, high-energy electron-irradiated and Sc-doped ZnGeP2 crystals were tested. The terahertz charge carrier mobilities were extracted from both the differential terahertz transmission at a specified photoexcitation condition and the Drude–Smith fitting of the photoconductivity spectra. The determined terahertz charge carrier mobility values are ~453 cm2/V·s for 4H-SiC and ~37 cm2/V·s for ZnGeP2 crystals. The charge carrier lifetimes and the contributions from various recombination mechanisms were determined at different injection levels using the model, which takes into account the influence of bulk and surface Shockley–Read–Hall (SRH) recombination, interband radiative transitions and interband and trap-assisted Auger recombination. It was found that ZnGeP2 possesses short charge carrier lifetimes (a~0.01 ps−1, b~6 × 10−19 cm3·ps−1 and c~7 × 10−40 cm6·ps−1) compared with 4H-SiC (a~0.001 ps−1, b~3 × 10−18 cm3·ps−1 and c~2 × 10−36 cm6·ps−1), i.e., τ~100 ps and τ~1 ns at the limit of relatively low injection, when the contribution from Auger and interband radiative recombination is small. The thermal annealing of as-grown ZnGeP2 crystals and the electron irradiation reduced the charge carrier lifetime, while their doping with 0.01 mass % of Sc increased the charger carrier lifetime and reduced mobility. It was found that the dark terahertz complex conductivity of the measured crystals is not fitted by the Drude–Smith model with reasonable parameters, while their terahertz photoconductivity can be fitted with acceptable accuracy.

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Section: Samplesupporting

confidence: 91%

Electrical Relaxation and Transport Properties of ZnGeP2 and 4H-SiC Crystals Measured with Terahertz Spectroscopy

et al. 2023

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“…Relatively small phonon contribution into the permittivity caused by covalent nature of the chemical bonding in ZnGeP 2 . Unlike [8], we have observed the shift of the phonon peaks at low temperatures. We have presented experimental reflectance spectra recorded at 300 K and 4 K for both polarizations in Table 2.…”

Section: Resultscontrasting

confidence: 57%

“…The presented in [8] temperature dependences of the strength of oscillators were shown with linear trend line; however, experimental points show rather parabolic dependence. Moreover, the same dependences in ZnP 2 and CdP 2 reported in [9,10] are also not linear.…”

Section: Introductionmentioning

confidence: 75%

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Optical phonon behaviors in ZnGeP2 single crystals from temperature dependent far-infrared reflectance spectra

Shportko

2015

Vibrational Spectroscopy

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“…In the THz range, radiation losses are caused by both intrinsic [24] and extrinsic [25] mechanisms. The latter are determined by external factors, primarily defects, and can be minimised by improving sample synthesis technology [26].…”

Section: Introductionmentioning

confidence: 99%

Assessment of the application of paratellurite for the acousto-optical deflection of terahertz rays based on broadband spectroscopy data

Komandin¹,

Nozdrin²,

Chuchupal³

et al. 2020

J. Phys. D: Appl. Phys.

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The rapid spatial guidance of terahertz (THz) radiation is a key problem in modern THz spectroscopy and imaging. Single-crystal α-TeO2 has advanced optical and elastic characteristics. This crystal widely used in acousto-optical devices in the visible and near-infrared (IR) ranges. Its application in the THz frequency range at temperatures of approximately 300 K is limited by high radiation absorption. We studied the electrodynamic characteristics of a paratellurite crystal in a wide frequency region at temperatures ranging from 77 to 300 K using pulsed broadband THz spectroscopy and IR Fourier spectroscopy. The temperature evolution of the complex refractive index, as well as the impact of phonon contributions and second-order processes on the absorption of radiation for polarisation along the crystallographic directions of [001] and [110], was evaluated. It was determined that at temperatures below 100 K, intrinsic absorption processes are significantly suppressed, which is mainly caused by a decrease in first- and second-order phonon contributions. The temperature dependencies of the refraction index and absorption coefficient of paratellurite in the THz range were obtained. We demonstrate that crystal cooling leads to a shift in the high-frequency boundary of the deflected THz radiation from 15 to 40 cm−1 along the [001] crystallographic axis.

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Mechanisms of loss formation in nonlinear optical crystals ZnGeP2 in the terahertz frequency range

Cited by 12 publications

References 20 publications

Electrical Relaxation and Transport Properties of ZnGeP2 and 4H-SiC Crystals Measured with Terahertz Spectroscopy

Electrical Relaxation and Transport Properties of ZnGeP2 and 4H-SiC Crystals Measured with Terahertz Spectroscopy

Optical phonon behaviors in ZnGeP2 single crystals from temperature dependent far-infrared reflectance spectra

Assessment of the application of paratellurite for the acousto-optical deflection of terahertz rays based on broadband spectroscopy data

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