Stabilization method for signal drifts in terahertz chemical microscopy

• Published in: Optics express Vol. 22; no. 2; pp. 1330 - 1335
• Main Authors: Kiwa, Toshihiko, Sakai, Kenji, Tsukada, Keiji
• Format: Journal Article
• Language: English
• Published: United States 27.01.2014
• Subjects: Algorithms; Equipment Design; Equipment Failure Analysis; Feedback; Image Enhancement - instrumentation; Image Enhancement - methods; Microscopy - instrumentation; Microscopy - methods; Molecular Imaging - instrumentation; Terahertz Imaging - instrumentation; Terahertz Imaging - methods
• ISSN: 1094-4087; 1094-4087
• DOI: 10.1364/oe.22.001330

A stabilization method for signal drifts in terahertz chemical microscopy (TCM) due to unexpected chemical potential changes in sample solutions was proposed and developed. The sensing plate was separated into two areas: a detection area and a control area. The detection area radiated a THz pulse whose amplitude was related to both the chemical reactions in the sample solutions and unexpected potential changes. The THz pulse from the control area was related only to unexpected potential changes. In the proposed system, the THz pulse from each area was interfered and detected. By adjusting the timing of the positive peak of the THz pulse from the detection area and the negative peak of the THz pulse from the control area, we detected the difference in both peaks as the interference signal. Thus, the signal deviation of 390 when the environmental condition changes in the temperature range of 38 °C and the pH range of 8.33 was stabilized to be the signal deviation of 31. As the result, the TCM with stabilization method could detect the signal shift of 121 when the 275-nmol/L immunoglobulin G was immobilized on the sensing plate.