Temperature Effects in an Acousto-Optic Modulator of Terahertz Radiation Based on Liquefied SF6 Gas

Abstract

The acousto-optic (AO) diffraction of terahertz (THz) radiation in liquefied sulfur hexafluoride (SF6) was investigated in various temperature regimes. It was found that with the increase in the temperature from +10 to +23∘C, the efficiency of the AO diffraction became one order higher at the same amplitude of the driving electrical signal. At the same time, the efficiency of the AO diffraction per 1 W of the sound power as well as the angular bandwidth of the efficient AO interaction were temperature independent within the measurement error. Increase of the resonant sound frequency with decreasing temperature and strong narrowing of the sound frequency bandwidth of the efficient AO interaction were detected.

Optimal Design of an Ultrasound Transducer for Efficient Acousto-Optic Modulation of Terahertz Radiation

“…Table 1 shows the values of the parameters of the AO modulator based on liquefied SF gas, obtained with various ultrasound transducers with a width d of 6 to 14 mm. The results for d = 14 mm was taken from our previous work [ 13 ]. For clarity, the results are presented in the form of graphs in Figure 6 .…”

“…The radiation beam was incident on the center of the input optical window of AO cell 3 ( mm) at the distance cm from the sound transducer. A detailed description of the AO cell is given in [ 13 ]. For observation of the diffracted radiation, the AO cell was turned through the Bragg angle, and a signal (modulated at a frequency of 10 Hz) from generator of electrical signals 4 was applied to the ultrasound transducer via amplifier 5.…”

“…As a result, the thickness of the transducer is comparable to its width. As far as we know, there are only a few works in which the AO diffraction of THz radiation in liquefied SF [ 3 , 4 , 13 ] was investigated. The results obtained in these works cannot be compared correctly because of the lack of data about the active electrical power consumed by the sound transducer.…”

Digital calibration technology and device design for SF6 hexafluoride

“…It is the core component of the sulfur hexafluoride leakage alarm system [1]. During the calibration process of sulfur hexafluoride leakage alarm sensor, it is necessary to design a calibration device with strong sealing performance, high safety level, and easy portability, which can adjust the concentration of sulfur hexafluoride gas in real-time, thus performing calibration of sulfur hexafluoride leakage alarm sensors with different accuracy [2].…”