Authors: V Mottamchetty A K Chaudhary
Publish Date: 2015/07/07
Volume: 90, Issue: 1, Pages: 73-78
Abstract
We report the improvised design of LTGaAs photoconductive antenna and pyroelectric detectorbased terahertz THz spectrophotometer by introducing bandpass filters The spectrophotometer provides direct optical/absorption information of materials in THz domain without using any signal processing devices such as lockin amplifier and delay arrangement etc which are required in conventional THz spectrometer Moreover obtained absorption results from spectrometer are less affected by laser fluctuations and inherent noises of the detector The laser pulses of duration ~15 fs at 80 MHz repetition rate are utilized in this spectrometer to generate THz radiation with good conversion efficiency η of the order 3 × 10−3 In addition emphasis is also given to understand the effect of single and twophoton absorption on generated THz power with respect to incident laser power density Absorption properties of packing materials such as paper Teflon transparency and rubber eraser sheets are investigated in terms of their attenuation coefficients and absorbance at 05 and 15 THz region in our newly designed THz spectrophotometer Our study demonstrates the significant information about their attenuation coefficients lying between 300 and 5000 dB/m The attenuation in THz power has been measured as a function of the paper thickness 03–15 mm The obtained results show the exponential growth in absorption with respect to paper thickness
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