Linearity of Fast and Highly Sensitive LiTaO$_{3}$ Pyroelectric Detectors in the Terahertz Range

In response to single-cycle THz pulses, we measured the linearity parameter of lithium tantalate pyroelectric detectors, over nearly three orders of magnitude in pulse energy, up to 2 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\mu$</tex-math></inline-formula>J. The response was linear up to 1 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\mu$</tex-math></inline-formula>J pulse energy and 25 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\mu$</tex-math></inline-formula>J/cm<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^{2}$</tex-math></inline-formula> energy flux, and sublinear at higher irradiations. This finding shows the importance of characterizing the detector response linearity for accurate THz metrology. The detectors had high sensitivity in single-pulse detection mode up to 10 kHz repetition rate.